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14<title>FFmpeg Documentation: 1. Introduction</title>
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42
43<a name="SEC1"></a>
44<table cellpadding="1" cellspacing="1" border="0">
45<tr><td valign="middle" align="left">[ &lt; ]</td>
46<td valign="middle" align="left">[<a href="#SEC2" title="Next section in reading order"> &gt; </a>]</td>
47<td valign="middle" align="left"> &nbsp; </td>
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49<td valign="middle" align="left">[ Up ]</td>
50<td valign="middle" align="left">[<a href="#SEC2" title="Next chapter"> &gt;&gt; </a>]</td>
51<td valign="middle" align="left"> &nbsp; </td>
52<td valign="middle" align="left"> &nbsp; </td>
53<td valign="middle" align="left"> &nbsp; </td>
54<td valign="middle" align="left"> &nbsp; </td>
55<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
56<td valign="middle" align="left">[Contents]</td>
57<td valign="middle" align="left">[Index]</td>
58<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
59</tr></table>
60<h1 class="chapter"> 1. Introduction </h1>
61
62<p>FFmpeg is a very fast video and audio converter. It can also grab from
63a live audio/video source.
64</p>
65<p>The command line interface is designed to be intuitive, in the sense
66that FFmpeg tries to figure out all parameters that can possibly be
67derived automatically. You usually only have to specify the target
68bitrate you want.
69</p>
70<p>FFmpeg can also convert from any sample rate to any other, and resize
71video on the fly with a high quality polyphase filter.
72</p>
73<hr size="6">
74<a name="SEC2"></a>
75<table cellpadding="1" cellspacing="1" border="0">
76<tr><td valign="middle" align="left">[<a href="#SEC1" title="Previous section in reading order"> &lt; </a>]</td>
77<td valign="middle" align="left">[<a href="#SEC3" title="Next section in reading order"> &gt; </a>]</td>
78<td valign="middle" align="left"> &nbsp; </td>
79<td valign="middle" align="left">[<a href="#SEC1" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
80<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
81<td valign="middle" align="left">[<a href="#SEC5" title="Next chapter"> &gt;&gt; </a>]</td>
82<td valign="middle" align="left"> &nbsp; </td>
83<td valign="middle" align="left"> &nbsp; </td>
84<td valign="middle" align="left"> &nbsp; </td>
85<td valign="middle" align="left"> &nbsp; </td>
86<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
87<td valign="middle" align="left">[Contents]</td>
88<td valign="middle" align="left">[Index]</td>
89<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
90</tr></table>
91<h1 class="chapter"> 2. Quick Start </h1>
92
93<hr size="6">
94<a name="SEC3"></a>
95<table cellpadding="1" cellspacing="1" border="0">
96<tr><td valign="middle" align="left">[<a href="#SEC2" title="Previous section in reading order"> &lt; </a>]</td>
97<td valign="middle" align="left">[<a href="#SEC4" title="Next section in reading order"> &gt; </a>]</td>
98<td valign="middle" align="left"> &nbsp; </td>
99<td valign="middle" align="left">[<a href="#SEC2" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
100<td valign="middle" align="left">[<a href="#SEC2" title="Up section"> Up </a>]</td>
101<td valign="middle" align="left">[<a href="#SEC5" title="Next chapter"> &gt;&gt; </a>]</td>
102<td valign="middle" align="left"> &nbsp; </td>
103<td valign="middle" align="left"> &nbsp; </td>
104<td valign="middle" align="left"> &nbsp; </td>
105<td valign="middle" align="left"> &nbsp; </td>
106<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
107<td valign="middle" align="left">[Contents]</td>
108<td valign="middle" align="left">[Index]</td>
109<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
110</tr></table>
111<h2 class="section"> 2.1 Video and Audio grabbing </h2>
112
113<p>FFmpeg can use a video4linux compatible video source and any Open Sound
114System audio source:
115</p>
116<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg /tmp/out.mpg
117</pre></td></tr></table>
118<p>Note that you must activate the right video source and channel before
119launching FFmpeg with any TV viewer such as xawtv
120(<a href="http://bytesex.org/xawtv/">http://bytesex.org/xawtv/</a>) by Gerd Knorr. You also
121have to set the audio recording levels correctly with a
122standard mixer.
123</p>
124<hr size="6">
125<a name="SEC4"></a>
126<table cellpadding="1" cellspacing="1" border="0">
127<tr><td valign="middle" align="left">[<a href="#SEC3" title="Previous section in reading order"> &lt; </a>]</td>
128<td valign="middle" align="left">[<a href="#SEC5" title="Next section in reading order"> &gt; </a>]</td>
129<td valign="middle" align="left"> &nbsp; </td>
130<td valign="middle" align="left">[<a href="#SEC2" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
131<td valign="middle" align="left">[<a href="#SEC2" title="Up section"> Up </a>]</td>
132<td valign="middle" align="left">[<a href="#SEC5" title="Next chapter"> &gt;&gt; </a>]</td>
133<td valign="middle" align="left"> &nbsp; </td>
134<td valign="middle" align="left"> &nbsp; </td>
135<td valign="middle" align="left"> &nbsp; </td>
136<td valign="middle" align="left"> &nbsp; </td>
137<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
138<td valign="middle" align="left">[Contents]</td>
139<td valign="middle" align="left">[Index]</td>
140<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
141</tr></table>
142<h2 class="section"> 2.2 Video and Audio file format conversion </h2>
143
144<p>* FFmpeg can use any supported file format and protocol as input:
145</p>
146<p>Examples:
147</p>
148<p>* You can use YUV files as input:
149</p>
150<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
151</pre></td></tr></table>
152<p>It will use the files:
153</p><table><tr><td>&nbsp;</td><td><pre class="example">/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
154/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
155</pre></td></tr></table>
156<p>The Y files use twice the resolution of the U and V files. They are
157raw files, without header. They can be generated by all decent video
158decoders. You must specify the size of the image with the <samp>`-s'</samp> option
159if FFmpeg cannot guess it.
160</p>
161<p>* You can input from a raw YUV420P file:
162</p>
163<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i /tmp/test.yuv /tmp/out.avi
164</pre></td></tr></table>
165<p>test.yuv is a file containing raw YUV planar data. Each frame is composed
166of the Y plane followed by the U and V planes at half vertical and
167horizontal resolution.
168</p>
169<p>* You can output to a raw YUV420P file:
170</p>
171<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i mydivx.avi hugefile.yuv
172</pre></td></tr></table>
173<p>* You can set several input files and output files:
174</p>
175<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
176</pre></td></tr></table>
177<p>Converts the audio file a.wav and the raw YUV video file a.yuv
178to MPEG file a.mpg.
179</p>
180<p>* You can also do audio and video conversions at the same time:
181</p>
182<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
183</pre></td></tr></table>
184<p>Converts a.wav to MPEG audio at 22050Hz sample rate.
185</p>
186<p>* You can encode to several formats at the same time and define a
187mapping from input stream to output streams:
188</p>
189<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
190</pre></td></tr></table>
191<p>Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
192file:index' specifies which input stream is used for each output
193stream, in the order of the definition of output streams.
194</p>
195<p>* You can transcode decrypted VOBs
196</p>
197<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
198</pre></td></tr></table>
199<p>This is a typical DVD ripping example; the input is a VOB file, the
200output an AVI file with MPEG-4 video and MP3 audio. Note that in this
201command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
202GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
203input video. Furthermore, the audio stream is MP3-encoded so you need
204to enable LAME support by passing <code>--enable-mp3lame</code> to configure.
205The mapping is particularly useful for DVD transcoding
206to get the desired audio language.
207</p>
208<p>NOTE: To see the supported input formats, use <code>ffmpeg -formats</code>.
209</p>
210<hr size="6">
211<a name="SEC5"></a>
212<table cellpadding="1" cellspacing="1" border="0">
213<tr><td valign="middle" align="left">[<a href="#SEC4" title="Previous section in reading order"> &lt; </a>]</td>
214<td valign="middle" align="left">[<a href="#SEC6" title="Next section in reading order"> &gt; </a>]</td>
215<td valign="middle" align="left"> &nbsp; </td>
216<td valign="middle" align="left">[<a href="#SEC2" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
217<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
218<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
219<td valign="middle" align="left"> &nbsp; </td>
220<td valign="middle" align="left"> &nbsp; </td>
221<td valign="middle" align="left"> &nbsp; </td>
222<td valign="middle" align="left"> &nbsp; </td>
223<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
224<td valign="middle" align="left">[Contents]</td>
225<td valign="middle" align="left">[Index]</td>
226<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
227</tr></table>
228<h1 class="chapter"> 3. Invocation </h1>
229
230<hr size="6">
231<a name="SEC6"></a>
232<table cellpadding="1" cellspacing="1" border="0">
233<tr><td valign="middle" align="left">[<a href="#SEC5" title="Previous section in reading order"> &lt; </a>]</td>
234<td valign="middle" align="left">[<a href="#SEC7" title="Next section in reading order"> &gt; </a>]</td>
235<td valign="middle" align="left"> &nbsp; </td>
236<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
237<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
238<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
239<td valign="middle" align="left"> &nbsp; </td>
240<td valign="middle" align="left"> &nbsp; </td>
241<td valign="middle" align="left"> &nbsp; </td>
242<td valign="middle" align="left"> &nbsp; </td>
243<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
244<td valign="middle" align="left">[Contents]</td>
245<td valign="middle" align="left">[Index]</td>
246<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
247</tr></table>
248<h2 class="section"> 3.1 Syntax </h2>
249
250<p>The generic syntax is:
251</p>
252<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg [[infile options][<samp>`-i'</samp> <var>infile</var>]]... {[outfile options] <var>outfile</var>}...
253</pre></td></tr></table><p>If no input file is given, audio/video grabbing is done.
254</p>
255<p>As a general rule, options are applied to the next specified
256file. For example, if you give the <samp>`-b 64'</samp> option, it sets the video
257bitrate of the next file. The format option may be needed for raw input
258files.
259</p>
260<p>By default, FFmpeg tries to convert as losslessly as possible: It
261uses the same audio and video parameters for the outputs as the one
262specified for the inputs.
263</p>
264<hr size="6">
265<a name="SEC7"></a>
266<table cellpadding="1" cellspacing="1" border="0">
267<tr><td valign="middle" align="left">[<a href="#SEC6" title="Previous section in reading order"> &lt; </a>]</td>
268<td valign="middle" align="left">[<a href="#SEC8" title="Next section in reading order"> &gt; </a>]</td>
269<td valign="middle" align="left"> &nbsp; </td>
270<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
271<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
272<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
273<td valign="middle" align="left"> &nbsp; </td>
274<td valign="middle" align="left"> &nbsp; </td>
275<td valign="middle" align="left"> &nbsp; </td>
276<td valign="middle" align="left"> &nbsp; </td>
277<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
278<td valign="middle" align="left">[Contents]</td>
279<td valign="middle" align="left">[Index]</td>
280<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
281</tr></table>
282<h2 class="section"> 3.2 Main options </h2>
283
284<dl compact="compact">
285<dt> <samp>`-L'</samp></dt>
286<dd><p>Show license.
287</p>
288</dd>
289<dt> <samp>`-h'</samp></dt>
290<dd><p>Show help.
291</p>
292</dd>
293<dt> <samp>`-formats'</samp></dt>
294<dd><p>Show available formats, codecs, protocols, ...
295</p>
296</dd>
297<dt> <samp>`-f fmt'</samp></dt>
298<dd><p>Force format.
299</p>
300</dd>
301<dt> <samp>`-i filename'</samp></dt>
302<dd><p>input filename
303</p>
304</dd>
305<dt> <samp>`-y'</samp></dt>
306<dd><p>Overwrite output files.
307</p>
308</dd>
309<dt> <samp>`-t duration'</samp></dt>
310<dd><p>Set the recording time in seconds.
311<code>hh:mm:ss[.xxx]</code> syntax is also supported.
312</p>
313</dd>
314<dt> <samp>`-ss position'</samp></dt>
315<dd><p>Seek to given time position in seconds.
316<code>hh:mm:ss[.xxx]</code> syntax is also supported.
317</p>
318</dd>
319<dt> <samp>`-title string'</samp></dt>
320<dd><p>Set the title.
321</p>
322</dd>
323<dt> <samp>`-author string'</samp></dt>
324<dd><p>Set the author.
325</p>
326</dd>
327<dt> <samp>`-copyright string'</samp></dt>
328<dd><p>Set the copyright.
329</p>
330</dd>
331<dt> <samp>`-comment string'</samp></dt>
332<dd><p>Set the comment.
333</p>
334</dd>
335<dt> <samp>`-target type'</samp></dt>
336<dd><p>Specify target file type (&quot;vcd&quot;, &quot;svcd&quot;, &quot;dvd&quot;, &quot;dv&quot;, &quot;pal-vcd&quot;,
337&quot;ntsc-svcd&quot;, ... ). All the format options (bitrate, codecs,
338buffer sizes) are then set automatically. You can just type:
339</p>
340<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
341</pre></td></tr></table>
342<p>Nevertheless you can specify additional options as long as you know
343they do not conflict with the standard, as in:
344</p>
345<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
346</pre></td></tr></table>
347</dd>
348<dt> <samp>`-hq'</samp></dt>
349<dd><p>Activate high quality settings.
350</p>
351</dd>
352<dt> <samp>`-itsoffset offset'</samp></dt>
353<dd><p>Set the input time offset in seconds.
354<code>[-]hh:mm:ss[.xxx]</code> syntax is also supported.
355This option affects all the input files that follow it.
356The offset is added to the timestamps of the input files.
357Specifying a positive offset means that the corresponding
358streams are delayed by 'offset' seconds.
359</p>
360</dd>
361</dl>
362
363<hr size="6">
364<a name="SEC8"></a>
365<table cellpadding="1" cellspacing="1" border="0">
366<tr><td valign="middle" align="left">[<a href="#SEC7" title="Previous section in reading order"> &lt; </a>]</td>
367<td valign="middle" align="left">[<a href="#SEC9" title="Next section in reading order"> &gt; </a>]</td>
368<td valign="middle" align="left"> &nbsp; </td>
369<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
370<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
371<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
372<td valign="middle" align="left"> &nbsp; </td>
373<td valign="middle" align="left"> &nbsp; </td>
374<td valign="middle" align="left"> &nbsp; </td>
375<td valign="middle" align="left"> &nbsp; </td>
376<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
377<td valign="middle" align="left">[Contents]</td>
378<td valign="middle" align="left">[Index]</td>
379<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
380</tr></table>
381<h2 class="section"> 3.3 Video Options </h2>
382
383<dl compact="compact">
384<dt> <samp>`-b bitrate'</samp></dt>
385<dd><p>Set the video bitrate in kbit/s (default = 200 kb/s).
386</p></dd>
387<dt> <samp>`-r fps'</samp></dt>
388<dd><p>Set frame rate (default = 25).
389</p></dd>
390<dt> <samp>`-s size'</samp></dt>
391<dd><p>Set frame size. The format is <samp>`wxh'</samp> (default = 160x128).
392The following abbreviations are recognized:
393</p><dl compact="compact">
394<dt> <samp>`sqcif'</samp></dt>
395<dd><p>128x96
396</p></dd>
397<dt> <samp>`qcif'</samp></dt>
398<dd><p>176x144
399</p></dd>
400<dt> <samp>`cif'</samp></dt>
401<dd><p>352x288
402</p></dd>
403<dt> <samp>`4cif'</samp></dt>
404<dd><p>704x576
405</p></dd>
406</dl>
407
408</dd>
409<dt> <samp>`-aspect aspect'</samp></dt>
410<dd><p>Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
411</p></dd>
412<dt> <samp>`-croptop size'</samp></dt>
413<dd><p>Set top crop band size (in pixels).
414</p></dd>
415<dt> <samp>`-cropbottom size'</samp></dt>
416<dd><p>Set bottom crop band size (in pixels).
417</p></dd>
418<dt> <samp>`-cropleft size'</samp></dt>
419<dd><p>Set left crop band size (in pixels).
420</p></dd>
421<dt> <samp>`-cropright size'</samp></dt>
422<dd><p>Set right crop band size (in pixels).
423</p></dd>
424<dt> <samp>`-padtop size'</samp></dt>
425<dd><p>Set top pad band size (in pixels).
426</p></dd>
427<dt> <samp>`-padbottom size'</samp></dt>
428<dd><p>Set bottom pad band size (in pixels).
429</p></dd>
430<dt> <samp>`-padleft size'</samp></dt>
431<dd><p>Set left pad band size (in pixels).
432</p></dd>
433<dt> <samp>`-padright size'</samp></dt>
434<dd><p>Set right pad band size (in pixels).
435</p></dd>
436<dt> <samp>`-padcolor (hex color)'</samp></dt>
437<dd><p>Set color of padded bands. The value for padcolor is expressed
438as a six digit hexadecimal number where the first two digits
439represent red, the middle two digits green and last two digits
440blue (default = 000000 (black)).
441</p></dd>
442<dt> <samp>`-vn'</samp></dt>
443<dd><p>Disable video recording.
444</p></dd>
445<dt> <samp>`-bt tolerance'</samp></dt>
446<dd><p>Set video bitrate tolerance (in kbit/s).
447</p></dd>
448<dt> <samp>`-maxrate bitrate'</samp></dt>
449<dd><p>Set max video bitrate tolerance (in kbit/s).
450</p></dd>
451<dt> <samp>`-minrate bitrate'</samp></dt>
452<dd><p>Set min video bitrate tolerance (in kbit/s).
453</p></dd>
454<dt> <samp>`-bufsize size'</samp></dt>
455<dd><p>Set rate control buffer size (in kbit).
456</p></dd>
457<dt> <samp>`-vcodec codec'</samp></dt>
458<dd><p>Force video codec to <var>codec</var>. Use the <code>copy</code> special value to
459tell that the raw codec data must be copied as is.
460</p></dd>
461<dt> <samp>`-sameq'</samp></dt>
462<dd><p>Use same video quality as source (implies VBR).
463</p>
464</dd>
465<dt> <samp>`-pass n'</samp></dt>
466<dd><p>Select the pass number (1 or 2). It is useful to do two pass
467encoding. The statistics of the video are recorded in the first
468pass and the video is generated at the exact requested bitrate
469in the second pass.
470</p>
471</dd>
472<dt> <samp>`-passlogfile file'</samp></dt>
473<dd><p>Set two pass logfile name to <var>file</var>.
474</p>
475</dd>
476</dl>
477
478<hr size="6">
479<a name="SEC9"></a>
480<table cellpadding="1" cellspacing="1" border="0">
481<tr><td valign="middle" align="left">[<a href="#SEC8" title="Previous section in reading order"> &lt; </a>]</td>
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483<td valign="middle" align="left"> &nbsp; </td>
484<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
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486<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
487<td valign="middle" align="left"> &nbsp; </td>
488<td valign="middle" align="left"> &nbsp; </td>
489<td valign="middle" align="left"> &nbsp; </td>
490<td valign="middle" align="left"> &nbsp; </td>
491<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
492<td valign="middle" align="left">[Contents]</td>
493<td valign="middle" align="left">[Index]</td>
494<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
495</tr></table>
496<h2 class="section"> 3.4 Advanced Video Options </h2>
497
498<dl compact="compact">
499<dt> <samp>`-g gop_size'</samp></dt>
500<dd><p>Set the group of pictures size.
501</p></dd>
502<dt> <samp>`-intra'</samp></dt>
503<dd><p>Use only intra frames.
504</p></dd>
505<dt> <samp>`-qscale q'</samp></dt>
506<dd><p>Use fixed video quantiser scale (VBR).
507</p></dd>
508<dt> <samp>`-qmin q'</samp></dt>
509<dd><p>minimum video quantiser scale (VBR)
510</p></dd>
511<dt> <samp>`-qmax q'</samp></dt>
512<dd><p>maximum video quantiser scale (VBR)
513</p></dd>
514<dt> <samp>`-qdiff q'</samp></dt>
515<dd><p>maximum difference between the quantiser scales (VBR)
516</p></dd>
517<dt> <samp>`-qblur blur'</samp></dt>
518<dd><p>video quantiser scale blur (VBR)
519</p></dd>
520<dt> <samp>`-qcomp compression'</samp></dt>
521<dd><p>video quantiser scale compression (VBR)
522</p>
523</dd>
524<dt> <samp>`-rc_init_cplx complexity'</samp></dt>
525<dd><p>initial complexity for single pass encoding
526</p></dd>
527<dt> <samp>`-b_qfactor factor'</samp></dt>
528<dd><p>qp factor between P- and B-frames
529</p></dd>
530<dt> <samp>`-i_qfactor factor'</samp></dt>
531<dd><p>qp factor between P- and I-frames
532</p></dd>
533<dt> <samp>`-b_qoffset offset'</samp></dt>
534<dd><p>qp offset between P- and B-frames
535</p></dd>
536<dt> <samp>`-i_qoffset offset'</samp></dt>
537<dd><p>qp offset between P- and I-frames
538</p></dd>
539<dt> <samp>`-rc_eq equation'</samp></dt>
540<dd><p>Set rate control equation (see section <a href="#SEC13">FFmpeg formula evaluator</a>) (default = <code>tex^qComp</code>).
541</p></dd>
542<dt> <samp>`-rc_override override'</samp></dt>
543<dd><p>rate control override for specific intervals
544</p></dd>
545<dt> <samp>`-me method'</samp></dt>
546<dd><p>Set motion estimation method to <var>method</var>.
547Available methods are (from lowest to best quality):
548</p><dl compact="compact">
549<dt> <samp>`zero'</samp></dt>
550<dd><p>Try just the (0, 0) vector.
551</p></dd>
552<dt> <samp>`phods'</samp></dt>
553<dt> <samp>`log'</samp></dt>
554<dt> <samp>`x1'</samp></dt>
555<dt> <samp>`epzs'</samp></dt>
556<dd><p>(default method)
557</p></dd>
558<dt> <samp>`full'</samp></dt>
559<dd><p>exhaustive search (slow and marginally better than epzs)
560</p></dd>
561</dl>
562
563</dd>
564<dt> <samp>`-dct_algo algo'</samp></dt>
565<dd><p>Set DCT algorithm to <var>algo</var>. Available values are:
566</p><dl compact="compact">
567<dt> <samp>`0'</samp></dt>
568<dd><p>FF_DCT_AUTO (default)
569</p></dd>
570<dt> <samp>`1'</samp></dt>
571<dd><p>FF_DCT_FASTINT
572</p></dd>
573<dt> <samp>`2'</samp></dt>
574<dd><p>FF_DCT_INT
575</p></dd>
576<dt> <samp>`3'</samp></dt>
577<dd><p>FF_DCT_MMX
578</p></dd>
579<dt> <samp>`4'</samp></dt>
580<dd><p>FF_DCT_MLIB
581</p></dd>
582<dt> <samp>`5'</samp></dt>
583<dd><p>FF_DCT_ALTIVEC
584</p></dd>
585</dl>
586
587</dd>
588<dt> <samp>`-idct_algo algo'</samp></dt>
589<dd><p>Set IDCT algorithm to <var>algo</var>. Available values are:
590</p><dl compact="compact">
591<dt> <samp>`0'</samp></dt>
592<dd><p>FF_IDCT_AUTO (default)
593</p></dd>
594<dt> <samp>`1'</samp></dt>
595<dd><p>FF_IDCT_INT
596</p></dd>
597<dt> <samp>`2'</samp></dt>
598<dd><p>FF_IDCT_SIMPLE
599</p></dd>
600<dt> <samp>`3'</samp></dt>
601<dd><p>FF_IDCT_SIMPLEMMX
602</p></dd>
603<dt> <samp>`4'</samp></dt>
604<dd><p>FF_IDCT_LIBMPEG2MMX
605</p></dd>
606<dt> <samp>`5'</samp></dt>
607<dd><p>FF_IDCT_PS2
608</p></dd>
609<dt> <samp>`6'</samp></dt>
610<dd><p>FF_IDCT_MLIB
611</p></dd>
612<dt> <samp>`7'</samp></dt>
613<dd><p>FF_IDCT_ARM
614</p></dd>
615<dt> <samp>`8'</samp></dt>
616<dd><p>FF_IDCT_ALTIVEC
617</p></dd>
618<dt> <samp>`9'</samp></dt>
619<dd><p>FF_IDCT_SH4
620</p></dd>
621<dt> <samp>`10'</samp></dt>
622<dd><p>FF_IDCT_SIMPLEARM
623</p></dd>
624</dl>
625
626</dd>
627<dt> <samp>`-er n'</samp></dt>
628<dd><p>Set error resilience to <var>n</var>.
629</p><dl compact="compact">
630<dt> <samp>`1'</samp></dt>
631<dd><p>FF_ER_CAREFUL (default)
632</p></dd>
633<dt> <samp>`2'</samp></dt>
634<dd><p>FF_ER_COMPLIANT
635</p></dd>
636<dt> <samp>`3'</samp></dt>
637<dd><p>FF_ER_AGGRESSIVE
638</p></dd>
639<dt> <samp>`4'</samp></dt>
640<dd><p>FF_ER_VERY_AGGRESSIVE
641</p></dd>
642</dl>
643
644</dd>
645<dt> <samp>`-ec bit_mask'</samp></dt>
646<dd><p>Set error concealment to <var>bit_mask</var>. <var>bit_mask</var> is a bit mask of
647the following values:
648</p><dl compact="compact">
649<dt> <samp>`1'</samp></dt>
650<dd><p>FF_EC_GUESS_MVS (default = enabled)
651</p></dd>
652<dt> <samp>`2'</samp></dt>
653<dd><p>FF_EC_DEBLOCK (default = enabled)
654</p></dd>
655</dl>
656
657</dd>
658<dt> <samp>`-bf frames'</samp></dt>
659<dd><p>Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
660</p></dd>
661<dt> <samp>`-mbd mode'</samp></dt>
662<dd><p>macroblock decision
663</p><dl compact="compact">
664<dt> <samp>`0'</samp></dt>
665<dd><p>FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
666</p></dd>
667<dt> <samp>`1'</samp></dt>
668<dd><p>FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
669</p></dd>
670<dt> <samp>`2'</samp></dt>
671<dd><p>FF_MB_DECISION_RD: rate distortion
672</p></dd>
673</dl>
674
675</dd>
676<dt> <samp>`-4mv'</samp></dt>
677<dd><p>Use four motion vector by macroblock (MPEG-4 only).
678</p></dd>
679<dt> <samp>`-part'</samp></dt>
680<dd><p>Use data partitioning (MPEG-4 only).
681</p></dd>
682<dt> <samp>`-bug param'</samp></dt>
683<dd><p>Work around encoder bugs that are not auto-detected.
684</p></dd>
685<dt> <samp>`-strict strictness'</samp></dt>
686<dd><p>How strictly to follow the standards.
687</p></dd>
688<dt> <samp>`-aic'</samp></dt>
689<dd><p>Enable Advanced intra coding (h263+).
690</p></dd>
691<dt> <samp>`-umv'</samp></dt>
692<dd><p>Enable Unlimited Motion Vector (h263+)
693</p>
694</dd>
695<dt> <samp>`-deinterlace'</samp></dt>
696<dd><p>Deinterlace pictures.
697</p></dd>
698<dt> <samp>`-interlace'</samp></dt>
699<dd><p>Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
700Use this option if your input file is interlaced and you want
701to keep the interlaced format for minimum losses.
702The alternative is to deinterlace the input stream with
703<samp>`-deinterlace'</samp>, but deinterlacing introduces losses.
704</p></dd>
705<dt> <samp>`-psnr'</samp></dt>
706<dd><p>Calculate PSNR of compressed frames.
707</p></dd>
708<dt> <samp>`-vstats'</samp></dt>
709<dd><p>Dump video coding statistics to <tt>`vstats_HHMMSS.log'</tt>.
710</p></dd>
711<dt> <samp>`-vhook module'</samp></dt>
712<dd><p>Insert video processing <var>module</var>. <var>module</var> contains the module
713name and its parameters separated by spaces.
714</p></dd>
715</dl>
716
717<hr size="6">
718<a name="SEC10"></a>
719<table cellpadding="1" cellspacing="1" border="0">
720<tr><td valign="middle" align="left">[<a href="#SEC9" title="Previous section in reading order"> &lt; </a>]</td>
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722<td valign="middle" align="left"> &nbsp; </td>
723<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
724<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
725<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
726<td valign="middle" align="left"> &nbsp; </td>
727<td valign="middle" align="left"> &nbsp; </td>
728<td valign="middle" align="left"> &nbsp; </td>
729<td valign="middle" align="left"> &nbsp; </td>
730<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
731<td valign="middle" align="left">[Contents]</td>
732<td valign="middle" align="left">[Index]</td>
733<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
734</tr></table>
735<h2 class="section"> 3.5 Audio Options </h2>
736
737<dl compact="compact">
738<dt> <samp>`-ar freq'</samp></dt>
739<dd><p>Set the audio sampling frequency (default = 44100 Hz).
740</p></dd>
741<dt> <samp>`-ab bitrate'</samp></dt>
742<dd><p>Set the audio bitrate in kbit/s (default = 64).
743</p></dd>
744<dt> <samp>`-ac channels'</samp></dt>
745<dd><p>Set the number of audio channels (default = 1).
746</p></dd>
747<dt> <samp>`-an'</samp></dt>
748<dd><p>Disable audio recording.
749</p></dd>
750<dt> <samp>`-acodec codec'</samp></dt>
751<dd><p>Force audio codec to <var>codec</var>. Use the <code>copy</code> special value to
752specify that the raw codec data must be copied as is.
753</p></dd>
754</dl>
755
756<hr size="6">
757<a name="SEC11"></a>
758<table cellpadding="1" cellspacing="1" border="0">
759<tr><td valign="middle" align="left">[<a href="#SEC10" title="Previous section in reading order"> &lt; </a>]</td>
760<td valign="middle" align="left">[<a href="#SEC12" title="Next section in reading order"> &gt; </a>]</td>
761<td valign="middle" align="left"> &nbsp; </td>
762<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
763<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
764<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
765<td valign="middle" align="left"> &nbsp; </td>
766<td valign="middle" align="left"> &nbsp; </td>
767<td valign="middle" align="left"> &nbsp; </td>
768<td valign="middle" align="left"> &nbsp; </td>
769<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
770<td valign="middle" align="left">[Contents]</td>
771<td valign="middle" align="left">[Index]</td>
772<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
773</tr></table>
774<h2 class="section"> 3.6 Audio/Video grab options </h2>
775
776<dl compact="compact">
777<dt> <samp>`-vd device'</samp></dt>
778<dd><p>sEt video grab device (e.g. <tt>`/dev/video0'</tt>).
779</p></dd>
780<dt> <samp>`-vc channel'</samp></dt>
781<dd><p>Set video grab channel (DV1394 only).
782</p></dd>
783<dt> <samp>`-tvstd standard'</samp></dt>
784<dd><p>Set television standard (NTSC, PAL (SECAM)).
785</p></dd>
786<dt> <samp>`-dv1394'</samp></dt>
787<dd><p>Set DV1394 grab.
788</p></dd>
789<dt> <samp>`-ad device'</samp></dt>
790<dd><p>Set audio device (e.g. <tt>`/dev/dsp'</tt>).
791</p></dd>
792</dl>
793
794<hr size="6">
795<a name="SEC12"></a>
796<table cellpadding="1" cellspacing="1" border="0">
797<tr><td valign="middle" align="left">[<a href="#SEC11" title="Previous section in reading order"> &lt; </a>]</td>
798<td valign="middle" align="left">[<a href="#SEC13" title="Next section in reading order"> &gt; </a>]</td>
799<td valign="middle" align="left"> &nbsp; </td>
800<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
801<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
802<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
803<td valign="middle" align="left"> &nbsp; </td>
804<td valign="middle" align="left"> &nbsp; </td>
805<td valign="middle" align="left"> &nbsp; </td>
806<td valign="middle" align="left"> &nbsp; </td>
807<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
808<td valign="middle" align="left">[Contents]</td>
809<td valign="middle" align="left">[Index]</td>
810<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
811</tr></table>
812<h2 class="section"> 3.7 Advanced options </h2>
813
814<dl compact="compact">
815<dt> <samp>`-map file:stream'</samp></dt>
816<dd><p>Set input stream mapping.
817</p></dd>
818<dt> <samp>`-debug'</samp></dt>
819<dd><p>Print specific debug info.
820</p></dd>
821<dt> <samp>`-benchmark'</samp></dt>
822<dd><p>Add timings for benchmarking.
823</p></dd>
824<dt> <samp>`-hex'</samp></dt>
825<dd><p>Dump each input packet.
826</p></dd>
827<dt> <samp>`-bitexact'</samp></dt>
828<dd><p>Only use bit exact algorithms (for codec testing).
829</p></dd>
830<dt> <samp>`-ps size'</samp></dt>
831<dd><p>Set packet size in bits.
832</p></dd>
833<dt> <samp>`-re'</samp></dt>
834<dd><p>Read input at native frame rate. Mainly used to simulate a grab device.
835</p></dd>
836<dt> <samp>`-loop'</samp></dt>
837<dd><p>Loop over the input stream. Currently it works only for image
838streams. This option is used for automatic FFserver testing.
839</p></dd>
840<dt> <samp>`-loop_output number_of_times'</samp></dt>
841<dd><p>Repeatedly loop output for formats that support looping such as animated GIF
842(0 will loop the output infinitely).
843</p></dd>
844</dl>
845
846<hr size="6">
847<a name="FFmpeg-formula-evaluator"></a>
848<a name="SEC13"></a>
849<table cellpadding="1" cellspacing="1" border="0">
850<tr><td valign="middle" align="left">[<a href="#SEC12" title="Previous section in reading order"> &lt; </a>]</td>
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852<td valign="middle" align="left"> &nbsp; </td>
853<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
854<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
855<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
856<td valign="middle" align="left"> &nbsp; </td>
857<td valign="middle" align="left"> &nbsp; </td>
858<td valign="middle" align="left"> &nbsp; </td>
859<td valign="middle" align="left"> &nbsp; </td>
860<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
861<td valign="middle" align="left">[Contents]</td>
862<td valign="middle" align="left">[Index]</td>
863<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
864</tr></table>
865<h2 class="section"> 3.8 FFmpeg formula evaluator </h2>
866
867<p>When evaluating a rate control string, FFmpeg uses an internal formula
868evaluator.
869</p>
870<p>The following binary operators are available: <code>+</code>, <code>-</code>,
871<code>*</code>, <code>/</code>, <code>^</code>.
872</p>
873<p>The following unary operators are available: <code>+</code>, <code>-</code>,
874<code>(...)</code>.
875</p>
876<p>The following functions are available:
877</p><dl compact="compact">
878<dt> <var>sinh(x)</var></dt>
879<dt> <var>cosh(x)</var></dt>
880<dt> <var>tanh(x)</var></dt>
881<dt> <var>sin(x)</var></dt>
882<dt> <var>cos(x)</var></dt>
883<dt> <var>tan(x)</var></dt>
884<dt> <var>exp(x)</var></dt>
885<dt> <var>log(x)</var></dt>
886<dt> <var>squish(x)</var></dt>
887<dt> <var>gauss(x)</var></dt>
888<dt> <var>abs(x)</var></dt>
889<dt> <var>max(x, y)</var></dt>
890<dt> <var>min(x, y)</var></dt>
891<dt> <var>gt(x, y)</var></dt>
892<dt> <var>lt(x, y)</var></dt>
893<dt> <var>eq(x, y)</var></dt>
894<dt> <var>bits2qp(bits)</var></dt>
895<dt> <var>qp2bits(qp)</var></dt>
896</dl>
897
898<p>The following constants are available:
899</p><dl compact="compact">
900<dt> <var>PI</var></dt>
901<dt> <var>E</var></dt>
902<dt> <var>iTex</var></dt>
903<dt> <var>pTex</var></dt>
904<dt> <var>tex</var></dt>
905<dt> <var>mv</var></dt>
906<dt> <var>fCode</var></dt>
907<dt> <var>iCount</var></dt>
908<dt> <var>mcVar</var></dt>
909<dt> <var>var</var></dt>
910<dt> <var>isI</var></dt>
911<dt> <var>isP</var></dt>
912<dt> <var>isB</var></dt>
913<dt> <var>avgQP</var></dt>
914<dt> <var>qComp</var></dt>
915<dt> <var>avgIITex</var></dt>
916<dt> <var>avgPITex</var></dt>
917<dt> <var>avgPPTex</var></dt>
918<dt> <var>avgBPTex</var></dt>
919<dt> <var>avgTex</var></dt>
920</dl>
921
922
923
924<hr size="6">
925<a name="SEC14"></a>
926<table cellpadding="1" cellspacing="1" border="0">
927<tr><td valign="middle" align="left">[<a href="#SEC13" title="Previous section in reading order"> &lt; </a>]</td>
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929<td valign="middle" align="left"> &nbsp; </td>
930<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
931<td valign="middle" align="left">[<a href="#SEC5" title="Up section"> Up </a>]</td>
932<td valign="middle" align="left">[<a href="#SEC15" title="Next chapter"> &gt;&gt; </a>]</td>
933<td valign="middle" align="left"> &nbsp; </td>
934<td valign="middle" align="left"> &nbsp; </td>
935<td valign="middle" align="left"> &nbsp; </td>
936<td valign="middle" align="left"> &nbsp; </td>
937<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
938<td valign="middle" align="left">[Contents]</td>
939<td valign="middle" align="left">[Index]</td>
940<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
941</tr></table>
942<h2 class="section"> 3.9 Protocols </h2>
943
944<p>The filename can be <tt>`-'</tt> to read from standard input or to write
945to standard output.
946</p>
947<p>FFmpeg also handles many protocols specified with an URL syntax.
948</p>
949<p>Use 'ffmpeg -formats' to see a list of the supported protocols.
950</p>
951<p>The protocol <code>http:</code> is currently used only to communicate with
952FFserver (see the FFserver documentation). When FFmpeg will be a
953video player it will also be used for streaming :-)
954</p>
955<hr size="6">
956<a name="SEC15"></a>
957<table cellpadding="1" cellspacing="1" border="0">
958<tr><td valign="middle" align="left">[<a href="#SEC14" title="Previous section in reading order"> &lt; </a>]</td>
959<td valign="middle" align="left">[<a href="#SEC16" title="Next section in reading order"> &gt; </a>]</td>
960<td valign="middle" align="left"> &nbsp; </td>
961<td valign="middle" align="left">[<a href="#SEC5" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
962<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
963<td valign="middle" align="left">[<a href="#SEC16" title="Next chapter"> &gt;&gt; </a>]</td>
964<td valign="middle" align="left"> &nbsp; </td>
965<td valign="middle" align="left"> &nbsp; </td>
966<td valign="middle" align="left"> &nbsp; </td>
967<td valign="middle" align="left"> &nbsp; </td>
968<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
969<td valign="middle" align="left">[Contents]</td>
970<td valign="middle" align="left">[Index]</td>
971<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
972</tr></table>
973<h1 class="chapter"> 4. Tips </h1>
974
975<ul class="toc">
976<li> For streaming at very low bitrate application, use a low frame rate
977and a small GOP size. This is especially true for RealVideo where
978the Linux player does not seem to be very fast, so it can miss
979frames. An example is:
980
981<table><tr><td>&nbsp;</td><td><pre class="example">ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
982</pre></td></tr></table>
983</li><li> The parameter 'q' which is displayed while encoding is the current
984quantizer. The value 1 indicates that a very good quality could
985be achieved. The value 31 indicates the worst quality. If q=31 appears
986too often, it means that the encoder cannot compress enough to meet
987your bitrate. You must either increase the bitrate, decrease the
988frame rate or decrease the frame size.
989
990</li><li> If your computer is not fast enough, you can speed up the
991compression at the expense of the compression ratio. You can use
992'-me zero' to speed up motion estimation, and '-intra' to disable
993motion estimation completely (you have only I-frames, which means it
994is about as good as JPEG compression).
995
996</li><li> To have very low audio bitrates, reduce the sampling frequency
997(down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
998
999</li><li> To have a constant quality (but a variable bitrate), use the option
1000'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
1001quality).
1002
1003</li><li> When converting video files, you can use the '-sameq' option which
1004uses the same quality factor in the encoder as in the decoder.
1005It allows almost lossless encoding.
1006
1007</li></ul>
1008
1009<hr size="6">
1010<a name="SEC16"></a>
1011<table cellpadding="1" cellspacing="1" border="0">
1012<tr><td valign="middle" align="left">[<a href="#SEC15" title="Previous section in reading order"> &lt; </a>]</td>
1013<td valign="middle" align="left">[<a href="#SEC17" title="Next section in reading order"> &gt; </a>]</td>
1014<td valign="middle" align="left"> &nbsp; </td>
1015<td valign="middle" align="left">[<a href="#SEC15" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1016<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
1017<td valign="middle" align="left">[<a href="#SEC21" title="Next chapter"> &gt;&gt; </a>]</td>
1018<td valign="middle" align="left"> &nbsp; </td>
1019<td valign="middle" align="left"> &nbsp; </td>
1020<td valign="middle" align="left"> &nbsp; </td>
1021<td valign="middle" align="left"> &nbsp; </td>
1022<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1023<td valign="middle" align="left">[Contents]</td>
1024<td valign="middle" align="left">[Index]</td>
1025<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1026</tr></table>
1027<h1 class="chapter"> 5. Supported File Formats and Codecs </h1>
1028
1029<p>You can use the <code>-formats</code> option to have an exhaustive list.
1030</p>
1031<hr size="6">
1032<a name="SEC17"></a>
1033<table cellpadding="1" cellspacing="1" border="0">
1034<tr><td valign="middle" align="left">[<a href="#SEC16" title="Previous section in reading order"> &lt; </a>]</td>
1035<td valign="middle" align="left">[<a href="#SEC18" title="Next section in reading order"> &gt; </a>]</td>
1036<td valign="middle" align="left"> &nbsp; </td>
1037<td valign="middle" align="left">[<a href="#SEC16" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1038<td valign="middle" align="left">[<a href="#SEC16" title="Up section"> Up </a>]</td>
1039<td valign="middle" align="left">[<a href="#SEC21" title="Next chapter"> &gt;&gt; </a>]</td>
1040<td valign="middle" align="left"> &nbsp; </td>
1041<td valign="middle" align="left"> &nbsp; </td>
1042<td valign="middle" align="left"> &nbsp; </td>
1043<td valign="middle" align="left"> &nbsp; </td>
1044<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1045<td valign="middle" align="left">[Contents]</td>
1046<td valign="middle" align="left">[Index]</td>
1047<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1048</tr></table>
1049<h2 class="section"> 5.1 File Formats </h2>
1050
1051<p>FFmpeg supports the following file formats through the <code>libavformat</code>
1052library:
1053</p>
1054<table>
1055<tr><td><p> Supported File Format </p></td><td><p> Encoding </p></td><td><p> Decoding </p></td><td><p> Comments
1056</p></td></tr>
1057<tr><td><p> MPEG audio </p></td><td><p> X </p></td><td><p> X
1058</p></td></tr>
1059<tr><td><p> MPEG-1 systems </p></td><td><p> X </p></td><td><p> X
1060</p></td><td><p> muxed audio and video
1061</p></td></tr>
1062<tr><td><p> MPEG-2 PS </p></td><td><p> X </p></td><td><p> X
1063</p></td><td><p> also known as <code>VOB</code> file
1064</p></td></tr>
1065<tr><td><p> MPEG-2 TS </p></td><td> </td><td><p> X
1066</p></td><td><p> also known as DVB Transport Stream
1067</p></td></tr>
1068<tr><td><p> ASF</p></td><td><p> X </p></td><td><p> X
1069</p></td></tr>
1070<tr><td><p> AVI</p></td><td><p> X </p></td><td><p> X
1071</p></td></tr>
1072<tr><td><p> WAV</p></td><td><p> X </p></td><td><p> X
1073</p></td></tr>
1074<tr><td><p> Macromedia Flash</p></td><td><p> X </p></td><td><p> X
1075</p></td><td><p> Only embedded audio is decoded.
1076</p></td></tr>
1077<tr><td><p> FLV </p></td><td><p> X </p></td><td><p> X
1078</p></td><td><p> Macromedia Flash video files
1079</p></td></tr>
1080<tr><td><p> Real Audio and Video </p></td><td><p> X </p></td><td><p> X
1081</p></td></tr>
1082<tr><td><p> Raw AC3 </p></td><td><p> X </p></td><td><p> X
1083</p></td></tr>
1084<tr><td><p> Raw MJPEG </p></td><td><p> X </p></td><td><p> X
1085</p></td></tr>
1086<tr><td><p> Raw MPEG video </p></td><td><p> X </p></td><td><p> X
1087</p></td></tr>
1088<tr><td><p> Raw PCM8/16 bits, mulaw/Alaw</p></td><td><p> X </p></td><td><p> X
1089</p></td></tr>
1090<tr><td><p> Raw CRI ADX audio </p></td><td><p> X </p></td><td><p> X
1091</p></td></tr>
1092<tr><td><p> Raw Shorten audio </p></td><td> </td><td><p> X
1093</p></td></tr>
1094<tr><td><p> SUN AU format </p></td><td><p> X </p></td><td><p> X
1095</p></td></tr>
1096<tr><td><p> NUT </p></td><td><p> X </p></td><td><p> X </p></td><td><p> NUT Open Container Format
1097</p></td></tr>
1098<tr><td><p> QuickTime </p></td><td><p> X </p></td><td><p> X
1099</p></td></tr>
1100<tr><td><p> MPEG-4 </p></td><td><p> X </p></td><td><p> X
1101</p></td><td><p> MPEG-4 is a variant of QuickTime.
1102</p></td></tr>
1103<tr><td><p> Raw MPEG4 video </p></td><td><p> X </p></td><td><p> X
1104</p></td></tr>
1105<tr><td><p> DV </p></td><td><p> X </p></td><td><p> X
1106</p></td></tr>
1107<tr><td><p> 4xm </p></td><td> </td><td><p> X
1108</p></td><td><p> 4X Technologies format, used in some games.
1109</p></td></tr>
1110<tr><td><p> Playstation STR </p></td><td> </td><td><p> X
1111</p></td></tr>
1112<tr><td><p> Id RoQ </p></td><td> </td><td><p> X
1113</p></td><td><p> Used in Quake III, Jedi Knight 2, other computer games.
1114</p></td></tr>
1115<tr><td><p> Interplay MVE </p></td><td> </td><td><p> X
1116</p></td><td><p> Format used in various Interplay computer games.
1117</p></td></tr>
1118<tr><td><p> WC3 Movie </p></td><td> </td><td><p> X
1119</p></td><td><p> Multimedia format used in Origin's Wing Commander III computer game.
1120</p></td></tr>
1121<tr><td><p> Sega FILM/CPK </p></td><td> </td><td><p> X
1122</p></td><td><p> Used in many Sega Saturn console games.
1123</p></td></tr>
1124<tr><td><p> Westwood Studios VQA/AUD </p></td><td> </td><td><p> X
1125</p></td><td><p> Multimedia formats used in Westwood Studios games.
1126</p></td></tr>
1127<tr><td><p> Id Cinematic (.cin) </p></td><td> </td><td><p> X
1128</p></td><td><p> Used in Quake II.
1129</p></td></tr>
1130<tr><td><p> FLIC format </p></td><td> </td><td><p> X
1131</p></td><td><p> .fli/.flc files
1132</p></td></tr>
1133<tr><td><p> Sierra VMD </p></td><td> </td><td><p> X
1134</p></td><td><p> Used in Sierra CD-ROM games.
1135</p></td></tr>
1136<tr><td><p> Sierra Online </p></td><td> </td><td><p> X
1137</p></td><td><p> .sol files used in Sierra Online games.
1138</p></td></tr>
1139<tr><td><p> Matroska </p></td><td> </td><td><p> X
1140</p></td></tr>
1141<tr><td><p> Electronic Arts Multimedia </p></td><td> </td><td><p> X
1142</p></td><td><p> Used in various EA games; files have extensions like WVE and UV2.
1143</p></td></tr>
1144<tr><td><p> Nullsoft Video (NSV) format </p></td><td> </td><td><p> X
1145</p></td></tr>
1146<tr><td><p> ADTS AAC audio </p></td><td><p> X </p></td><td><p> X
1147</p></td></tr>
1148<tr><td><p> Creative VOC </p></td><td><p> X </p></td><td><p> X </p></td><td><p> Created for the Sound Blaster Pro.
1149</p></td></tr>
1150<tr><td><p> American Laser Games MM </p></td><td> </td><td><p> X
1151</p></td><td><p> Multimedia format used in games like Mad Dog McCree
1152</p></td></tr>
1153<tr><td><p> AVS </p></td><td> </td><td><p> X
1154</p></td><td><p> Multimedia format used by the Creature Shock game.
1155</p></td></tr>
1156<tr><td><p> Smacker </p></td><td> </td><td><p> X
1157</p></td><td><p> Multimedia format used by many games.
1158</p></td></tr>
1159</table>
1160
1161<p><code>X</code> means that encoding (resp. decoding) is supported.
1162</p>
1163<hr size="6">
1164<a name="SEC18"></a>
1165<table cellpadding="1" cellspacing="1" border="0">
1166<tr><td valign="middle" align="left">[<a href="#SEC17" title="Previous section in reading order"> &lt; </a>]</td>
1167<td valign="middle" align="left">[<a href="#SEC19" title="Next section in reading order"> &gt; </a>]</td>
1168<td valign="middle" align="left"> &nbsp; </td>
1169<td valign="middle" align="left">[<a href="#SEC16" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1170<td valign="middle" align="left">[<a href="#SEC16" title="Up section"> Up </a>]</td>
1171<td valign="middle" align="left">[<a href="#SEC21" title="Next chapter"> &gt;&gt; </a>]</td>
1172<td valign="middle" align="left"> &nbsp; </td>
1173<td valign="middle" align="left"> &nbsp; </td>
1174<td valign="middle" align="left"> &nbsp; </td>
1175<td valign="middle" align="left"> &nbsp; </td>
1176<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1177<td valign="middle" align="left">[Contents]</td>
1178<td valign="middle" align="left">[Index]</td>
1179<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1180</tr></table>
1181<h2 class="section"> 5.2 Image Formats </h2>
1182
1183<p>FFmpeg can read and write images for each frame of a video sequence. The
1184following image formats are supported:
1185</p>
1186<table>
1187<tr><td><p> Supported Image Format </p></td><td><p> Encoding </p></td><td><p> Decoding </p></td><td><p> Comments
1188</p></td></tr>
1189<tr><td><p> PGM, PPM </p></td><td><p> X </p></td><td><p> X
1190</p></td></tr>
1191<tr><td><p> PAM </p></td><td><p> X </p></td><td><p> X </p></td><td><p> PAM is a PNM extension with alpha support.
1192</p></td></tr>
1193<tr><td><p> PGMYUV </p></td><td><p> X </p></td><td><p> X </p></td><td><p> PGM with U and V components in YUV 4:2:0
1194</p></td></tr>
1195<tr><td><p> JPEG </p></td><td><p> X </p></td><td><p> X </p></td><td><p> Progressive JPEG is not supported.
1196</p></td></tr>
1197<tr><td><p> .Y.U.V </p></td><td><p> X </p></td><td><p> X </p></td><td><p> one raw file per component
1198</p></td></tr>
1199<tr><td><p> animated GIF </p></td><td><p> X </p></td><td><p> X </p></td><td><p> Only uncompressed GIFs are generated.
1200</p></td></tr>
1201<tr><td><p> PNG </p></td><td><p> X </p></td><td><p> X </p></td><td><p> 2 bit and 4 bit/pixel not supported yet.
1202</p></td></tr>
1203<tr><td><p> SGI </p></td><td><p> X </p></td><td><p> X </p></td><td><p> SGI RGB image format
1204</p></td></tr>
1205</table>
1206
1207<p><code>X</code> means that encoding (resp. decoding) is supported.
1208</p>
1209<hr size="6">
1210<a name="SEC19"></a>
1211<table cellpadding="1" cellspacing="1" border="0">
1212<tr><td valign="middle" align="left">[<a href="#SEC18" title="Previous section in reading order"> &lt; </a>]</td>
1213<td valign="middle" align="left">[<a href="#SEC20" title="Next section in reading order"> &gt; </a>]</td>
1214<td valign="middle" align="left"> &nbsp; </td>
1215<td valign="middle" align="left">[<a href="#SEC16" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1216<td valign="middle" align="left">[<a href="#SEC16" title="Up section"> Up </a>]</td>
1217<td valign="middle" align="left">[<a href="#SEC21" title="Next chapter"> &gt;&gt; </a>]</td>
1218<td valign="middle" align="left"> &nbsp; </td>
1219<td valign="middle" align="left"> &nbsp; </td>
1220<td valign="middle" align="left"> &nbsp; </td>
1221<td valign="middle" align="left"> &nbsp; </td>
1222<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1223<td valign="middle" align="left">[Contents]</td>
1224<td valign="middle" align="left">[Index]</td>
1225<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1226</tr></table>
1227<h2 class="section"> 5.3 Video Codecs </h2>
1228
1229<table>
1230<tr><td><p> Supported Codec </p></td><td><p> Encoding </p></td><td><p> Decoding </p></td><td><p> Comments
1231</p></td></tr>
1232<tr><td><p> MPEG-1 video </p></td><td><p> X </p></td><td><p> X
1233</p></td></tr>
1234<tr><td><p> MPEG-2 video </p></td><td><p> X </p></td><td><p> X
1235</p></td></tr>
1236<tr><td><p> MPEG-4 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> also known as DivX4/5
1237</p></td></tr>
1238<tr><td><p> MSMPEG4 V1 </p></td><td><p> X </p></td><td><p> X
1239</p></td></tr>
1240<tr><td><p> MSMPEG4 V2 </p></td><td><p> X </p></td><td><p> X
1241</p></td></tr>
1242<tr><td><p> MSMPEG4 V3 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> also known as DivX3
1243</p></td></tr>
1244<tr><td><p> WMV7 </p></td><td><p> X </p></td><td><p> X
1245</p></td></tr>
1246<tr><td><p> WMV8 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> not completely working
1247</p></td></tr>
1248<tr><td><p> H.261 </p></td><td><p> X </p></td><td><p> X
1249</p></td></tr>
1250<tr><td><p> H.263(+) </p></td><td><p> X </p></td><td><p> X </p></td><td><p> also known as RealVideo 1.0
1251</p></td></tr>
1252<tr><td><p> H.264 </p></td><td> </td><td><p> X
1253</p></td></tr>
1254<tr><td><p> RealVideo 1.0 </p></td><td><p> X </p></td><td><p> X
1255</p></td></tr>
1256<tr><td><p> RealVideo 2.0 </p></td><td><p> X </p></td><td><p> X
1257</p></td></tr>
1258<tr><td><p> MJPEG </p></td><td><p> X </p></td><td><p> X
1259</p></td></tr>
1260<tr><td><p> lossless MJPEG </p></td><td><p> X </p></td><td><p> X
1261</p></td></tr>
1262<tr><td><p> JPEG-LS </p></td><td><p> X </p></td><td><p> X </p></td><td><p> fourcc: MJLS, lossless and near-lossless is supported
1263</p></td></tr>
1264<tr><td><p> Apple MJPEG-B </p></td><td> </td><td><p> X
1265</p></td></tr>
1266<tr><td><p> Sunplus MJPEG </p></td><td> </td><td><p> X </p></td><td><p> fourcc: SP5X
1267</p></td></tr>
1268<tr><td><p> DV </p></td><td><p> X </p></td><td><p> X
1269</p></td></tr>
1270<tr><td><p> HuffYUV </p></td><td><p> X </p></td><td><p> X
1271</p></td></tr>
1272<tr><td><p> FFmpeg Video 1 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> experimental lossless codec (fourcc: FFV1)
1273</p></td></tr>
1274<tr><td><p> FFmpeg Snow </p></td><td><p> X </p></td><td><p> X </p></td><td><p> experimental wavelet codec (fourcc: SNOW)
1275</p></td></tr>
1276<tr><td><p> Asus v1 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> fourcc: ASV1
1277</p></td></tr>
1278<tr><td><p> Asus v2 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> fourcc: ASV2
1279</p></td></tr>
1280<tr><td><p> Creative YUV </p></td><td> </td><td><p> X </p></td><td><p> fourcc: CYUV
1281</p></td></tr>
1282<tr><td><p> Sorenson Video 1 </p></td><td><p> X </p></td><td><p> X </p></td><td><p> fourcc: SVQ1
1283</p></td></tr>
1284<tr><td><p> Sorenson Video 3 </p></td><td> </td><td><p> X </p></td><td><p> fourcc: SVQ3
1285</p></td></tr>
1286<tr><td><p> On2 VP3 </p></td><td> </td><td><p> X </p></td><td><p> still experimental
1287</p></td></tr>
1288<tr><td><p> Theora </p></td><td> </td><td><p> X </p></td><td><p> still experimental
1289</p></td></tr>
1290<tr><td><p> Intel Indeo 3 </p></td><td> </td><td><p> X
1291</p></td></tr>
1292<tr><td><p> FLV </p></td><td><p> X </p></td><td><p> X </p></td><td><p> Sorenson H.263 used in Flash
1293</p></td></tr>
1294<tr><td><p> Flash Screen Video </p></td><td> </td><td><p> X </p></td><td><p> fourcc: FSV1
1295</p></td></tr>
1296<tr><td><p> ATI VCR1 </p></td><td> </td><td><p> X </p></td><td><p> fourcc: VCR1
1297</p></td></tr>
1298<tr><td><p> ATI VCR2 </p></td><td> </td><td><p> X </p></td><td><p> fourcc: VCR2
1299</p></td></tr>
1300<tr><td><p> Cirrus Logic AccuPak </p></td><td> </td><td><p> X </p></td><td><p> fourcc: CLJR
1301</p></td></tr>
1302<tr><td><p> 4X Video </p></td><td> </td><td><p> X </p></td><td><p> Used in certain computer games.
1303</p></td></tr>
1304<tr><td><p> Sony Playstation MDEC </p></td><td> </td><td><p> X
1305</p></td></tr>
1306<tr><td><p> Id RoQ </p></td><td> </td><td><p> X </p></td><td><p> Used in Quake III, Jedi Knight 2, other computer games.
1307</p></td></tr>
1308<tr><td><p> Xan/WC3 </p></td><td> </td><td><p> X </p></td><td><p> Used in Wing Commander III .MVE files.
1309</p></td></tr>
1310<tr><td><p> Interplay Video </p></td><td> </td><td><p> X </p></td><td><p> Used in Interplay .MVE files.
1311</p></td></tr>
1312<tr><td><p> Apple Animation </p></td><td> </td><td><p> X </p></td><td><p> fourcc: 'rle '
1313</p></td></tr>
1314<tr><td><p> Apple Graphics </p></td><td> </td><td><p> X </p></td><td><p> fourcc: 'smc '
1315</p></td></tr>
1316<tr><td><p> Apple Video </p></td><td> </td><td><p> X </p></td><td><p> fourcc: rpza
1317</p></td></tr>
1318<tr><td><p> Apple QuickDraw </p></td><td> </td><td><p> X </p></td><td><p> fourcc: qdrw
1319</p></td></tr>
1320<tr><td><p> Cinepak </p></td><td> </td><td><p> X
1321</p></td></tr>
1322<tr><td><p> Microsoft RLE </p></td><td> </td><td><p> X
1323</p></td></tr>
1324<tr><td><p> Microsoft Video-1 </p></td><td> </td><td><p> X
1325</p></td></tr>
1326<tr><td><p> Westwood VQA </p></td><td> </td><td><p> X
1327</p></td></tr>
1328<tr><td><p> Id Cinematic Video </p></td><td> </td><td><p> X </p></td><td><p> Used in Quake II.
1329</p></td></tr>
1330<tr><td><p> Planar RGB </p></td><td> </td><td><p> X </p></td><td><p> fourcc: 8BPS
1331</p></td></tr>
1332<tr><td><p> FLIC video </p></td><td> </td><td><p> X
1333</p></td></tr>
1334<tr><td><p> Duck TrueMotion v1 </p></td><td> </td><td><p> X </p></td><td><p> fourcc: DUCK
1335</p></td></tr>
1336<tr><td><p> Duck TrueMotion v2 </p></td><td> </td><td><p> X </p></td><td><p> fourcc: TM20
1337</p></td></tr>
1338<tr><td><p> VMD Video </p></td><td> </td><td><p> X </p></td><td><p> Used in Sierra VMD files.
1339</p></td></tr>
1340<tr><td><p> MSZH </p></td><td> </td><td><p> X </p></td><td><p> Part of LCL
1341</p></td></tr>
1342<tr><td><p> ZLIB </p></td><td><p> X </p></td><td><p> X </p></td><td><p> Part of LCL, encoder experimental
1343</p></td></tr>
1344<tr><td><p> TechSmith Camtasia </p></td><td> </td><td><p> X </p></td><td><p> fourcc: TSCC
1345</p></td></tr>
1346<tr><td><p> IBM Ultimotion </p></td><td> </td><td><p> X </p></td><td><p> fourcc: ULTI
1347</p></td></tr>
1348<tr><td><p> Miro VideoXL </p></td><td> </td><td><p> X </p></td><td><p> fourcc: VIXL
1349</p></td></tr>
1350<tr><td><p> QPEG </p></td><td> </td><td><p> X </p></td><td><p> fourccs: QPEG, Q1.0, Q1.1
1351</p></td></tr>
1352<tr><td><p> LOCO </p></td><td> </td><td><p> X </p></td><td>
1353</td></tr>
1354<tr><td><p> Winnov WNV1 </p></td><td> </td><td><p> X </p></td><td>
1355</td></tr>
1356<tr><td><p> Autodesk Animator Studio Codec </p></td><td> </td><td><p> X </p></td><td><p> fourcc: AASC
1357</p></td></tr>
1358<tr><td><p> Fraps FPS1 </p></td><td> </td><td><p> X </p></td><td>
1359</td></tr>
1360<tr><td><p> CamStudio </p></td><td> </td><td><p> X </p></td><td><p> fourcc: CSCD
1361</p></td></tr>
1362<tr><td><p> American Laser Games Video </p></td><td> </td><td><p> X </p></td><td><p> Used in games like Mad Dog McCree
1363</p></td></tr>
1364<tr><td><p> ZMBV </p></td><td> </td><td><p> X </p></td><td>
1365</td></tr>
1366<tr><td><p> AVS Video </p></td><td> </td><td><p> X </p></td><td><p> Video encoding used by the Creature Shock game.
1367</p></td></tr>
1368<tr><td><p> Smacker Video </p></td><td> </td><td><p> X </p></td><td><p> Video encoding used in Smacker.
1369</p></td></tr>
1370<tr><td><p> RTjpeg </p></td><td> </td><td><p> X </p></td><td><p> Video encoding used in NuppelVideo files.
1371</p></td></tr>
1372<tr><td><p> KMVC </p></td><td> </td><td><p> X </p></td><td><p> Codec used in Worms games.
1373</p></td></tr>
1374</table>
1375
1376<p><code>X</code> means that encoding (resp. decoding) is supported.
1377</p>
1378<p>See <a href="http://mplayerhq.hu/~michael/codec-features.html">http://mplayerhq.hu/~michael/codec-features.html</a> to
1379get a precise comparison of the FFmpeg MPEG-4 codec compared to
1380other implementations.
1381</p>
1382<hr size="6">
1383<a name="SEC20"></a>
1384<table cellpadding="1" cellspacing="1" border="0">
1385<tr><td valign="middle" align="left">[<a href="#SEC19" title="Previous section in reading order"> &lt; </a>]</td>
1386<td valign="middle" align="left">[<a href="#SEC21" title="Next section in reading order"> &gt; </a>]</td>
1387<td valign="middle" align="left"> &nbsp; </td>
1388<td valign="middle" align="left">[<a href="#SEC16" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1389<td valign="middle" align="left">[<a href="#SEC16" title="Up section"> Up </a>]</td>
1390<td valign="middle" align="left">[<a href="#SEC21" title="Next chapter"> &gt;&gt; </a>]</td>
1391<td valign="middle" align="left"> &nbsp; </td>
1392<td valign="middle" align="left"> &nbsp; </td>
1393<td valign="middle" align="left"> &nbsp; </td>
1394<td valign="middle" align="left"> &nbsp; </td>
1395<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1396<td valign="middle" align="left">[Contents]</td>
1397<td valign="middle" align="left">[Index]</td>
1398<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1399</tr></table>
1400<h2 class="section"> 5.4 Audio Codecs </h2>
1401
1402<table>
1403<tr><td><p> Supported Codec </p></td><td><p> Encoding </p></td><td><p> Decoding </p></td><td><p> Comments
1404</p></td></tr>
1405<tr><td><p> MPEG audio layer 2 </p></td><td><p> IX </p></td><td><p> IX
1406</p></td></tr>
1407<tr><td><p> MPEG audio layer 1/3 </p></td><td><p> IX </p></td><td><p> IX
1408</p></td><td><p> MP3 encoding is supported through the external library LAME.
1409</p></td></tr>
1410<tr><td><p> AC3 </p></td><td><p> IX </p></td><td><p> IX
1411</p></td><td><p> liba52 is used internally for decoding.
1412</p></td></tr>
1413<tr><td><p> Vorbis </p></td><td><p> X </p></td><td><p> X
1414</p></td><td><p> Supported through the external library libvorbis.
1415</p></td></tr>
1416<tr><td><p> WMA V1/V2 </p></td><td> </td><td><p> X
1417</p></td></tr>
1418<tr><td><p> AAC </p></td><td><p> X </p></td><td><p> X
1419</p></td><td><p> Supported through the external library libfaac/libfaad.
1420</p></td></tr>
1421<tr><td><p> Microsoft ADPCM </p></td><td><p> X </p></td><td><p> X
1422</p></td></tr>
1423<tr><td><p> MS IMA ADPCM </p></td><td><p> X </p></td><td><p> X
1424</p></td></tr>
1425<tr><td><p> QT IMA ADPCM </p></td><td> </td><td><p> X
1426</p></td></tr>
1427<tr><td><p> 4X IMA ADPCM </p></td><td> </td><td><p> X
1428</p></td></tr>
1429<tr><td><p> G.726 ADPCM </p></td><td><p> X </p></td><td><p> X
1430</p></td></tr>
1431<tr><td><p> Duck DK3 IMA ADPCM </p></td><td> </td><td><p> X
1432</p></td><td><p> Used in some Sega Saturn console games.
1433</p></td></tr>
1434<tr><td><p> Duck DK4 IMA ADPCM </p></td><td> </td><td><p> X
1435</p></td><td><p> Used in some Sega Saturn console games.
1436</p></td></tr>
1437<tr><td><p> Westwood Studios IMA ADPCM </p></td><td> </td><td><p> X
1438</p></td><td><p> Used in Westwood Studios games like Command and Conquer.
1439</p></td></tr>
1440<tr><td><p> SMJPEG IMA ADPCM </p></td><td> </td><td><p> X
1441</p></td><td><p> Used in certain Loki game ports.
1442</p></td></tr>
1443<tr><td><p> CD-ROM XA ADPCM </p></td><td> </td><td><p> X
1444</p></td></tr>
1445<tr><td><p> CRI ADX ADPCM </p></td><td><p> X </p></td><td><p> X
1446</p></td><td><p> Used in Sega Dreamcast games.
1447</p></td></tr>
1448<tr><td><p> Electronic Arts ADPCM </p></td><td> </td><td><p> X
1449</p></td><td><p> Used in various EA titles.
1450</p></td></tr>
1451<tr><td><p> Creative ADPCM </p></td><td> </td><td><p> X
1452</p></td><td><p> 16 -&gt; 4, 8 -&gt; 4, 8 -&gt; 3, 8 -&gt; 2
1453</p></td></tr>
1454<tr><td><p> RA144 </p></td><td> </td><td><p> X
1455</p></td><td><p> Real 14400 bit/s codec
1456</p></td></tr>
1457<tr><td><p> RA288 </p></td><td> </td><td><p> X
1458</p></td><td><p> Real 28800 bit/s codec
1459</p></td></tr>
1460<tr><td><p> RADnet </p></td><td><p> X </p></td><td><p> IX
1461</p></td><td><p> Real low bitrate AC3 codec, liba52 is used for decoding.
1462</p></td></tr>
1463<tr><td><p> AMR-NB </p></td><td><p> X </p></td><td><p> X
1464</p></td><td><p> Supported through an external library.
1465</p></td></tr>
1466<tr><td><p> AMR-WB </p></td><td><p> X </p></td><td><p> X
1467</p></td><td><p> Supported through an external library.
1468</p></td></tr>
1469<tr><td><p> DV audio </p></td><td> </td><td><p> X
1470</p></td></tr>
1471<tr><td><p> Id RoQ DPCM </p></td><td> </td><td><p> X
1472</p></td><td><p> Used in Quake III, Jedi Knight 2, other computer games.
1473</p></td></tr>
1474<tr><td><p> Interplay MVE DPCM </p></td><td> </td><td><p> X
1475</p></td><td><p> Used in various Interplay computer games.
1476</p></td></tr>
1477<tr><td><p> Xan DPCM </p></td><td> </td><td><p> X
1478</p></td><td><p> Used in Origin's Wing Commander IV AVI files.
1479</p></td></tr>
1480<tr><td><p> Sierra Online DPCM </p></td><td> </td><td><p> X
1481</p></td><td><p> Used in Sierra Online game audio files.
1482</p></td></tr>
1483<tr><td><p> Apple MACE 3 </p></td><td> </td><td><p> X
1484</p></td></tr>
1485<tr><td><p> Apple MACE 6 </p></td><td> </td><td><p> X
1486</p></td></tr>
1487<tr><td><p> FLAC lossless audio </p></td><td> </td><td><p> X
1488</p></td></tr>
1489<tr><td><p> Shorten lossless audio </p></td><td> </td><td><p> X
1490</p></td></tr>
1491<tr><td><p> Apple lossless audio </p></td><td> </td><td><p> X
1492</p></td><td><p> QuickTime fourcc 'alac'
1493</p></td></tr>
1494<tr><td><p> FFmpeg Sonic </p></td><td><p> X </p></td><td><p> X
1495</p></td><td><p> experimental lossy/lossless codec
1496</p></td></tr>
1497<tr><td><p> Qdesign QDM2 </p></td><td> </td><td><p> X
1498</p></td><td><p> there are still some distortions
1499</p></td></tr>
1500<tr><td><p> Real COOK </p></td><td> </td><td><p> X
1501</p></td><td><p> All versions except 5.1 are supported
1502</p></td></tr>
1503<tr><td><p> DSP Group TrueSpeech </p></td><td> </td><td><p> X
1504</p></td></tr>
1505<tr><td><p> True Audio (TTA) </p></td><td> </td><td><p> X
1506</p></td></tr>
1507<tr><td><p> Smacker Audio </p></td><td> </td><td><p> X
1508</p></td></tr>
1509</table>
1510
1511<p><code>X</code> means that encoding (resp. decoding) is supported.
1512</p>
1513<p><code>I</code> means that an integer-only version is available, too (ensures high
1514performance on systems without hardware floating point support).
1515</p>
1516<hr size="6">
1517<a name="SEC21"></a>
1518<table cellpadding="1" cellspacing="1" border="0">
1519<tr><td valign="middle" align="left">[<a href="#SEC20" title="Previous section in reading order"> &lt; </a>]</td>
1520<td valign="middle" align="left">[<a href="#SEC22" title="Next section in reading order"> &gt; </a>]</td>
1521<td valign="middle" align="left"> &nbsp; </td>
1522<td valign="middle" align="left">[<a href="#SEC16" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1523<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
1524<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1525<td valign="middle" align="left"> &nbsp; </td>
1526<td valign="middle" align="left"> &nbsp; </td>
1527<td valign="middle" align="left"> &nbsp; </td>
1528<td valign="middle" align="left"> &nbsp; </td>
1529<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1530<td valign="middle" align="left">[Contents]</td>
1531<td valign="middle" align="left">[Index]</td>
1532<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1533</tr></table>
1534<h1 class="chapter"> 6. Platform Specific information </h1>
1535
1536<hr size="6">
1537<a name="SEC22"></a>
1538<table cellpadding="1" cellspacing="1" border="0">
1539<tr><td valign="middle" align="left">[<a href="#SEC21" title="Previous section in reading order"> &lt; </a>]</td>
1540<td valign="middle" align="left">[<a href="#SEC23" title="Next section in reading order"> &gt; </a>]</td>
1541<td valign="middle" align="left"> &nbsp; </td>
1542<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1543<td valign="middle" align="left">[<a href="#SEC21" title="Up section"> Up </a>]</td>
1544<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1545<td valign="middle" align="left"> &nbsp; </td>
1546<td valign="middle" align="left"> &nbsp; </td>
1547<td valign="middle" align="left"> &nbsp; </td>
1548<td valign="middle" align="left"> &nbsp; </td>
1549<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1550<td valign="middle" align="left">[Contents]</td>
1551<td valign="middle" align="left">[Index]</td>
1552<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1553</tr></table>
1554<h2 class="section"> 6.1 Linux </h2>
1555
1556<p>FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
1557preferred compiler now for FFmpeg. All future optimizations will depend on
1558features only found in GCC 3.2.
1559</p>
1560<hr size="6">
1561<a name="SEC23"></a>
1562<table cellpadding="1" cellspacing="1" border="0">
1563<tr><td valign="middle" align="left">[<a href="#SEC22" title="Previous section in reading order"> &lt; </a>]</td>
1564<td valign="middle" align="left">[<a href="#SEC24" title="Next section in reading order"> &gt; </a>]</td>
1565<td valign="middle" align="left"> &nbsp; </td>
1566<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1567<td valign="middle" align="left">[<a href="#SEC21" title="Up section"> Up </a>]</td>
1568<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1569<td valign="middle" align="left"> &nbsp; </td>
1570<td valign="middle" align="left"> &nbsp; </td>
1571<td valign="middle" align="left"> &nbsp; </td>
1572<td valign="middle" align="left"> &nbsp; </td>
1573<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1574<td valign="middle" align="left">[Contents]</td>
1575<td valign="middle" align="left">[Index]</td>
1576<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1577</tr></table>
1578<h2 class="section"> 6.2 BSD </h2>
1579
1580<p>BSD make will not build FFmpeg, you need to install and use GNU Make
1581(<tt>`gmake'</tt>).
1582</p>
1583<hr size="6">
1584<a name="SEC24"></a>
1585<table cellpadding="1" cellspacing="1" border="0">
1586<tr><td valign="middle" align="left">[<a href="#SEC23" title="Previous section in reading order"> &lt; </a>]</td>
1587<td valign="middle" align="left">[<a href="#SEC25" title="Next section in reading order"> &gt; </a>]</td>
1588<td valign="middle" align="left"> &nbsp; </td>
1589<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1590<td valign="middle" align="left">[<a href="#SEC21" title="Up section"> Up </a>]</td>
1591<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1592<td valign="middle" align="left"> &nbsp; </td>
1593<td valign="middle" align="left"> &nbsp; </td>
1594<td valign="middle" align="left"> &nbsp; </td>
1595<td valign="middle" align="left"> &nbsp; </td>
1596<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1597<td valign="middle" align="left">[Contents]</td>
1598<td valign="middle" align="left">[Index]</td>
1599<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1600</tr></table>
1601<h2 class="section"> 6.3 Windows </h2>
1602
1603<hr size="6">
1604<a name="SEC25"></a>
1605<table cellpadding="1" cellspacing="1" border="0">
1606<tr><td valign="middle" align="left">[<a href="#SEC24" title="Previous section in reading order"> &lt; </a>]</td>
1607<td valign="middle" align="left">[<a href="#SEC26" title="Next section in reading order"> &gt; </a>]</td>
1608<td valign="middle" align="left"> &nbsp; </td>
1609<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1610<td valign="middle" align="left">[<a href="#SEC24" title="Up section"> Up </a>]</td>
1611<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1612<td valign="middle" align="left"> &nbsp; </td>
1613<td valign="middle" align="left"> &nbsp; </td>
1614<td valign="middle" align="left"> &nbsp; </td>
1615<td valign="middle" align="left"> &nbsp; </td>
1616<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1617<td valign="middle" align="left">[Contents]</td>
1618<td valign="middle" align="left">[Index]</td>
1619<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1620</tr></table>
1621<h3 class="subsection"> 6.3.1 Native Windows compilation </h3>
1622
1623<ul class="toc">
1624<li> Install the current versions of MSYS and MinGW from
1625<a href="http://www.mingw.org/">http://www.mingw.org/</a>. You can find detailed installation
1626instructions in the download section and the FAQ.
1627
1628</li><li> If you want to test the FFplay, also download
1629the MinGW development library of SDL 1.2.x
1630(<tt>`SDL-devel-1.2.x-mingw32.tar.gz'</tt>) from
1631<a href="http://www.libsdl.org">http://www.libsdl.org</a>. Unpack it in a temporary directory, and
1632unpack the archive <tt>`i386-mingw32msvc.tar.gz'</tt> in the MinGW tool
1633directory. Edit the <tt>`sdl-config'</tt> script so that it gives the
1634correct SDL directory when invoked.
1635
1636</li><li> Extract the current version of FFmpeg.
1637
1638</li><li> Start the MSYS shell (file <tt>`msys.bat'</tt>).
1639
1640</li><li> Change to the FFmpeg directory and follow
1641 the instructions of how to compile FFmpeg (file
1642<tt>`INSTALL'</tt>). Usually, launching <tt>`./configure'</tt> and <tt>`make'</tt>
1643suffices. If you have problems using SDL, verify that
1644<tt>`sdl-config'</tt> can be launched from the MSYS command line.
1645
1646</li><li> You can install FFmpeg in <tt>`Program Files/FFmpeg'</tt> by typing
1647<tt>`make install'</tt>. Don't forget to copy <tt>`SDL.dll'</tt> to the place
1648you launch <tt>`ffplay'</tt> from.
1649
1650</li></ul>
1651
1652<p>Notes:
1653</p><ul class="toc">
1654<li> The target <tt>`make wininstaller'</tt> can be used to create a
1655Nullsoft based Windows installer for FFmpeg and FFplay. <tt>`SDL.dll'</tt>
1656must be copied to the FFmpeg directory in order to build the
1657installer.
1658
1659</li><li> By using <code>./configure --enable-shared</code> when configuring FFmpeg,
1660you can build <tt>`avcodec.dll'</tt> and <tt>`avformat.dll'</tt>. With
1661<code>make install</code> you install the FFmpeg DLLs and the associated
1662headers in <tt>`Program Files/FFmpeg'</tt>.
1663
1664</li><li> Visual C++ compatibility: If you used <code>./configure --enable-shared</code>
1665when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
1666C++ <code>lib</code> tool to build <code>avcodec.lib</code> and
1667<code>avformat.lib</code>. With these libraries you can link your Visual C++
1668code directly with the FFmpeg DLLs (see below).
1669
1670</li></ul>
1671
1672<hr size="6">
1673<a name="SEC26"></a>
1674<table cellpadding="1" cellspacing="1" border="0">
1675<tr><td valign="middle" align="left">[<a href="#SEC25" title="Previous section in reading order"> &lt; </a>]</td>
1676<td valign="middle" align="left">[<a href="#SEC27" title="Next section in reading order"> &gt; </a>]</td>
1677<td valign="middle" align="left"> &nbsp; </td>
1678<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1679<td valign="middle" align="left">[<a href="#SEC24" title="Up section"> Up </a>]</td>
1680<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1681<td valign="middle" align="left"> &nbsp; </td>
1682<td valign="middle" align="left"> &nbsp; </td>
1683<td valign="middle" align="left"> &nbsp; </td>
1684<td valign="middle" align="left"> &nbsp; </td>
1685<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1686<td valign="middle" align="left">[Contents]</td>
1687<td valign="middle" align="left">[Index]</td>
1688<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1689</tr></table>
1690<h3 class="subsection"> 6.3.2 Visual C++ compatibility </h3>
1691
1692<p>FFmpeg will not compile under Visual C++ - and it has too many
1693dependencies on the GCC compiler to make a port viable. However,
1694if you want to use the FFmpeg libraries in your own applications,
1695you can still compile those applications using Visual C++. An
1696important restriction to this is that you have to use the
1697dynamically linked versions of the FFmpeg libraries (i.e. the
1698DLLs), and you have to make sure that Visual-C++-compatible
1699import libraries are created during the FFmpeg build process.
1700</p>
1701<p>This description of how to use the FFmpeg libraries with Visual C++ is
1702based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1703version, you might have to modify the procedures slightly.
1704</p>
1705<p>Here are the step-by-step instructions for building the FFmpeg libraries
1706so they can be used with Visual C++:
1707</p>
1708<ol>
1709<li> Install Visual C++ (if you haven't done so already).
1710
1711</li><li> Install MinGW and MSYS as described above.
1712
1713</li><li> Add a call to <tt>`vcvars32.bat'</tt> (which sets up the environment
1714variables for the Visual C++ tools) as the first line of
1715<tt>`msys.bat'</tt>. The standard location for <tt>`vcvars32.bat'</tt> is
1716<tt>`C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat'</tt>,
1717and the standard location for <tt>`msys.bat'</tt> is
1718<tt>`C:\msys\1.0\msys.bat'</tt>. If this corresponds to your setup, add the
1719following line as the first line of <tt>`msys.bat'</tt>:
1720
1721<p><code>call &quot;C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat&quot;</code>
1722</p>
1723</li><li> Start the MSYS shell (file <tt>`msys.bat'</tt>) and type <code>link.exe</code>.
1724If you get a help message with the command line options of <code>link.exe</code>,
1725this means your environment variables are set up correctly, the
1726Microsoft linker is on the path and will be used by FFmpeg to
1727create Visual-C++-compatible import libraries.
1728
1729</li><li> Extract the current version of FFmpeg and change to the FFmpeg directory.
1730
1731</li><li> Type the command
1732<code>./configure --enable-shared --disable-static --enable-memalign-hack</code>
1733to configure and, if that didn't produce any errors,
1734type <code>make</code> to build FFmpeg.
1735
1736</li><li> The subdirectories <tt>`libavformat'</tt>, <tt>`libavcodec'</tt>, and
1737<tt>`libavutil'</tt> should now contain the files <tt>`avformat.dll'</tt>,
1738<tt>`avformat.lib'</tt>, <tt>`avcodec.dll'</tt>, <tt>`avcodec.lib'</tt>,
1739<tt>`avutil.dll'</tt>, and <tt>`avutil.lib'</tt>, respectively. Copy the three
1740DLLs to your System32 directory (typically <tt>`C:\Windows\System32'</tt>).
1741
1742</li></ol>
1743
1744<p>And here is how to use these libraries with Visual C++:
1745</p>
1746<ol>
1747<li> Create a new console application (&quot;File / New / Project&quot;) and then
1748select &quot;Win32 Console Application&quot;. On the appropriate page of the
1749Application Wizard, uncheck the &quot;Precompiled headers&quot; option.
1750
1751</li><li> Write the source code for your application, or, for testing, just
1752copy the code from an existing sample application into the source file
1753that Visual C++ has already created for you. (Note that your source
1754filehas to have a <code>.cpp</code> extension; otherwise, Visual C++ won't
1755compile the FFmpeg headers correctly because in C mode, it doesn't
1756recognize the <code>inline</code> keyword.) For example, you can copy
1757<tt>`output_example.c'</tt> from the FFmpeg distribution (but you will
1758have to make minor modifications so the code will compile under
1759C++, see below).
1760
1761</li><li> Open the &quot;Project / Properties&quot; dialog box. In the &quot;Configuration&quot;
1762combo box, select &quot;All Configurations&quot; so that the changes you make will
1763affect both debug and release builds. In the tree view on the left hand
1764side, select &quot;C/C++ / General&quot;, then edit the &quot;Additional Include
1765Directories&quot; setting to contain the complete paths to the
1766<tt>`libavformat'</tt>, <tt>`libavcodec'</tt>, and <tt>`libavutil'</tt>
1767subdirectories of your FFmpeg directory. Note that the directories have
1768to be separated using semicolons. Now select &quot;Linker / General&quot; from the
1769tree view and edit the &quot;Additional Library Directories&quot; setting to
1770contain the same three directories.
1771
1772</li><li> Still in the &quot;Project / Properties&quot; dialog box, select &quot;Linker / Input&quot;
1773from the tree view, then add the files <tt>`avformat.lib'</tt>,
1774<tt>`avcodec.lib'</tt>, and <tt>`avutil.lib'</tt> to the end of the &quot;Additional
1775Dependencies&quot;. Note that the names of the libraries have to be separated
1776using spaces.
1777
1778</li><li> Now, select &quot;C/C++ / Code Generation&quot; from the tree view. Select
1779&quot;Debug&quot; in the &quot;Configuration&quot; combo box. Make sure that &quot;Runtime
1780Library&quot; is set to &quot;Multi-threaded Debug DLL&quot;. Then, select &quot;Release&quot; in
1781the &quot;Configuration&quot; combo box and make sure that &quot;Runtime Library&quot; is
1782set to &quot;Multi-threaded DLL&quot;.
1783
1784</li><li> Click &quot;OK&quot; to close the &quot;Project / Properties&quot; dialog box and build
1785the application. Hopefully, it should compile and run cleanly. If you
1786used <tt>`output_example.c'</tt> as your sample application, you will get a
1787few compiler errors, but they are easy to fix. The first type of error
1788occurs because Visual C++ doesn't allow an <code>int</code> to be converted to
1789an <code>enum</code> without a cast. To solve the problem, insert the required
1790casts (this error occurs once for a <code>CodecID</code> and once for a
1791<code>CodecType</code>). The second type of error occurs because C++ requires
1792the return value of <code>malloc</code> to be cast to the exact type of the
1793pointer it is being assigned to. Visual C++ will complain that, for
1794example, <code>(void *)</code> is being assigned to <code>(uint8_t *)</code> without
1795an explicit cast. So insert an explicit cast in these places to silence
1796the compiler. The third type of error occurs because the <code>snprintf</code>
1797library function is called <code>_snprintf</code> under Visual C++. So just
1798add an underscore to fix the problem. With these changes,
1799<tt>`output_example.c'</tt> should compile under Visual C++, and the
1800resulting executable should produce valid video files.
1801
1802</li></ol>
1803
1804<hr size="6">
1805<a name="SEC27"></a>
1806<table cellpadding="1" cellspacing="1" border="0">
1807<tr><td valign="middle" align="left">[<a href="#SEC26" title="Previous section in reading order"> &lt; </a>]</td>
1808<td valign="middle" align="left">[<a href="#SEC28" title="Next section in reading order"> &gt; </a>]</td>
1809<td valign="middle" align="left"> &nbsp; </td>
1810<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1811<td valign="middle" align="left">[<a href="#SEC24" title="Up section"> Up </a>]</td>
1812<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1813<td valign="middle" align="left"> &nbsp; </td>
1814<td valign="middle" align="left"> &nbsp; </td>
1815<td valign="middle" align="left"> &nbsp; </td>
1816<td valign="middle" align="left"> &nbsp; </td>
1817<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1818<td valign="middle" align="left">[Contents]</td>
1819<td valign="middle" align="left">[Index]</td>
1820<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1821</tr></table>
1822<h3 class="subsection"> 6.3.3 Cross compilation for Windows with Linux </h3>
1823
1824<p>You must use the MinGW cross compilation tools available at
1825<a href="http://www.mingw.org/">http://www.mingw.org/</a>.
1826</p>
1827<p>Then configure FFmpeg with the following options:
1828</p><table><tr><td>&nbsp;</td><td><pre class="example">./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1829</pre></td></tr></table><p>(you can change the cross-prefix according to the prefix chosen for the
1830MinGW tools).
1831</p>
1832<p>Then you can easily test FFmpeg with Wine
1833(<a href="http://www.winehq.com/">http://www.winehq.com/</a>).
1834</p>
1835<hr size="6">
1836<a name="SEC28"></a>
1837<table cellpadding="1" cellspacing="1" border="0">
1838<tr><td valign="middle" align="left">[<a href="#SEC27" title="Previous section in reading order"> &lt; </a>]</td>
1839<td valign="middle" align="left">[<a href="#SEC29" title="Next section in reading order"> &gt; </a>]</td>
1840<td valign="middle" align="left"> &nbsp; </td>
1841<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1842<td valign="middle" align="left">[<a href="#SEC21" title="Up section"> Up </a>]</td>
1843<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1844<td valign="middle" align="left"> &nbsp; </td>
1845<td valign="middle" align="left"> &nbsp; </td>
1846<td valign="middle" align="left"> &nbsp; </td>
1847<td valign="middle" align="left"> &nbsp; </td>
1848<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1849<td valign="middle" align="left">[Contents]</td>
1850<td valign="middle" align="left">[Index]</td>
1851<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1852</tr></table>
1853<h2 class="section"> 6.4 Mac OS X </h2>
1854
1855<hr size="6">
1856<a name="SEC29"></a>
1857<table cellpadding="1" cellspacing="1" border="0">
1858<tr><td valign="middle" align="left">[<a href="#SEC28" title="Previous section in reading order"> &lt; </a>]</td>
1859<td valign="middle" align="left">[<a href="#SEC30" title="Next section in reading order"> &gt; </a>]</td>
1860<td valign="middle" align="left"> &nbsp; </td>
1861<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1862<td valign="middle" align="left">[<a href="#SEC21" title="Up section"> Up </a>]</td>
1863<td valign="middle" align="left">[<a href="#SEC30" title="Next chapter"> &gt;&gt; </a>]</td>
1864<td valign="middle" align="left"> &nbsp; </td>
1865<td valign="middle" align="left"> &nbsp; </td>
1866<td valign="middle" align="left"> &nbsp; </td>
1867<td valign="middle" align="left"> &nbsp; </td>
1868<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1869<td valign="middle" align="left">[Contents]</td>
1870<td valign="middle" align="left">[Index]</td>
1871<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1872</tr></table>
1873<h2 class="section"> 6.5 BeOS </h2>
1874
1875<p>The configure script should guess the configuration itself.
1876Networking support is currently not finished.
1877errno issues fixed by Andrew Bachmann.
1878</p>
1879<p>Old stuff:
1880</p>
1881<p>François Revol - revol at free dot fr - April 2002
1882</p>
1883<p>The configure script should guess the configuration itself,
1884however I still didn't test building on the net_server version of BeOS.
1885</p>
1886<p>FFserver is broken (needs poll() implementation).
1887</p>
1888<p>There are still issues with errno codes, which are negative in BeOS, and
1889that FFmpeg negates when returning. This ends up turning errors into
1890valid results, then crashes.
1891(To be fixed)
1892</p>
1893<hr size="6">
1894<a name="SEC30"></a>
1895<table cellpadding="1" cellspacing="1" border="0">
1896<tr><td valign="middle" align="left">[<a href="#SEC29" title="Previous section in reading order"> &lt; </a>]</td>
1897<td valign="middle" align="left">[<a href="#SEC31" title="Next section in reading order"> &gt; </a>]</td>
1898<td valign="middle" align="left"> &nbsp; </td>
1899<td valign="middle" align="left">[<a href="#SEC21" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1900<td valign="middle" align="left">[<a href="#SEC1" title="Up section"> Up </a>]</td>
1901<td valign="middle" align="left">[ &gt;&gt; ]</td>
1902<td valign="middle" align="left"> &nbsp; </td>
1903<td valign="middle" align="left"> &nbsp; </td>
1904<td valign="middle" align="left"> &nbsp; </td>
1905<td valign="middle" align="left"> &nbsp; </td>
1906<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1907<td valign="middle" align="left">[Contents]</td>
1908<td valign="middle" align="left">[Index]</td>
1909<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1910</tr></table>
1911<h1 class="chapter"> 7. Developers Guide </h1>
1912
1913<hr size="6">
1914<a name="SEC31"></a>
1915<table cellpadding="1" cellspacing="1" border="0">
1916<tr><td valign="middle" align="left">[<a href="#SEC30" title="Previous section in reading order"> &lt; </a>]</td>
1917<td valign="middle" align="left">[<a href="#SEC32" title="Next section in reading order"> &gt; </a>]</td>
1918<td valign="middle" align="left"> &nbsp; </td>
1919<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1920<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
1921<td valign="middle" align="left">[ &gt;&gt; ]</td>
1922<td valign="middle" align="left"> &nbsp; </td>
1923<td valign="middle" align="left"> &nbsp; </td>
1924<td valign="middle" align="left"> &nbsp; </td>
1925<td valign="middle" align="left"> &nbsp; </td>
1926<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1927<td valign="middle" align="left">[Contents]</td>
1928<td valign="middle" align="left">[Index]</td>
1929<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1930</tr></table>
1931<h2 class="section"> 7.1 API </h2>
1932<ul class="toc">
1933<li> libavcodec is the library containing the codecs (both encoding and
1934decoding). Look at <tt>`libavcodec/apiexample.c'</tt> to see how to use it.
1935
1936</li><li> libavformat is the library containing the file format handling (mux and
1937demux code for several formats). Look at <tt>`ffplay.c'</tt> to use it in a
1938player. See <tt>`output_example.c'</tt> to use it to generate audio or video
1939streams.
1940
1941</li></ul>
1942
1943<hr size="6">
1944<a name="SEC32"></a>
1945<table cellpadding="1" cellspacing="1" border="0">
1946<tr><td valign="middle" align="left">[<a href="#SEC31" title="Previous section in reading order"> &lt; </a>]</td>
1947<td valign="middle" align="left">[<a href="#SEC33" title="Next section in reading order"> &gt; </a>]</td>
1948<td valign="middle" align="left"> &nbsp; </td>
1949<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1950<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
1951<td valign="middle" align="left">[ &gt;&gt; ]</td>
1952<td valign="middle" align="left"> &nbsp; </td>
1953<td valign="middle" align="left"> &nbsp; </td>
1954<td valign="middle" align="left"> &nbsp; </td>
1955<td valign="middle" align="left"> &nbsp; </td>
1956<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1957<td valign="middle" align="left">[Contents]</td>
1958<td valign="middle" align="left">[Index]</td>
1959<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1960</tr></table>
1961<h2 class="section"> 7.2 Integrating libavcodec or libavformat in your program </h2>
1962
1963<p>You can integrate all the source code of the libraries to link them
1964statically to avoid any version problem. All you need is to provide a
1965'config.mak' and a 'config.h' in the parent directory. See the defines
1966generated by ./configure to understand what is needed.
1967</p>
1968<p>You can use libavcodec or libavformat in your commercial program, but
1969<em>any patch you make must be published</em>. The best way to proceed is
1970to send your patches to the FFmpeg mailing list.
1971</p>
1972<hr size="6">
1973<a name="Coding-Rules"></a>
1974<a name="SEC33"></a>
1975<table cellpadding="1" cellspacing="1" border="0">
1976<tr><td valign="middle" align="left">[<a href="#SEC32" title="Previous section in reading order"> &lt; </a>]</td>
1977<td valign="middle" align="left">[<a href="#SEC34" title="Next section in reading order"> &gt; </a>]</td>
1978<td valign="middle" align="left"> &nbsp; </td>
1979<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
1980<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
1981<td valign="middle" align="left">[ &gt;&gt; ]</td>
1982<td valign="middle" align="left"> &nbsp; </td>
1983<td valign="middle" align="left"> &nbsp; </td>
1984<td valign="middle" align="left"> &nbsp; </td>
1985<td valign="middle" align="left"> &nbsp; </td>
1986<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
1987<td valign="middle" align="left">[Contents]</td>
1988<td valign="middle" align="left">[Index]</td>
1989<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
1990</tr></table>
1991<h2 class="section"> 7.3 Coding Rules </h2>
1992
1993<p>FFmpeg is programmed in the ISO C90 language with a few additional
1994features from ISO C99, namely:
1995</p><ul>
1996<li>
1997the <samp>`inline'</samp> keyword;
1998</li><li>
1999<samp>`//'</samp> comments;
2000</li><li>
2001designated struct initializers (<samp>`struct s x = { .i = 17 };'</samp>)
2002</li><li>
2003compound literals (<samp>`x = (struct s) { 17, 23 };'</samp>)
2004</li></ul>
2005
2006<p>These features are supported by all compilers we care about, so we won't
2007accept patches to remove their use unless they absolutely don't impair
2008clarity and performance.
2009</p>
2010<p>All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
2011compiles with several other compilers, such as the Compaq ccc compiler
2012or Sun Studio 9, and we would like to keep it that way unless it would
2013be exceedingly involved. To ensure compatibility, please don't use any
2014additional C99 features or GCC extensions. Especially watch out for:
2015</p><ul>
2016<li>
2017mixing statements and declarations;
2018</li><li>
2019<samp>`long long'</samp> (use <samp>`int64_t'</samp> instead);
2020</li><li>
2021<samp>`__attribute__'</samp> not protected by <samp>`#ifdef __GNUC__'</samp> or similar;
2022</li><li>
2023GCC statement expressions (<samp>`(x = ({ int y = 4; y; })'</samp>).
2024</li></ul>
2025
2026<p>Indent size is 4.
2027The presentation is the one specified by 'indent -i4 -kr -nut'.
2028The TAB character is forbidden outside of Makefiles as is any
2029form of trailing whitespace. Commits containing either will be
2030rejected by the Subversion repository.
2031</p>
2032<p>Main priority in FFmpeg is simplicity and small code size (=less
2033bugs).
2034</p>
2035<p>Comments: Use the JavaDoc/Doxygen
2036format (see examples below) so that code documentation
2037can be generated automatically. All nontrivial functions should have a comment
2038above them explaining what the function does, even if it's just one sentence.
2039All structures and their member variables should be documented, too.
2040</p><table><tr><td>&nbsp;</td><td><pre class="example">/**
2041 * @file mpeg.c
2042 * MPEG codec.
2043 * @author ...
2044 */
2045
2046/**
2047 * Summary sentence.
2048 * more text ...
2049 * ...
2050 */
2051typedef struct Foobar{
2052 int var1; /**&lt; var1 description */
2053 int var2; ///&lt; var2 description
2054 /** var3 description */
2055 int var3;
2056} Foobar;
2057
2058/**
2059 * Summary sentence.
2060 * more text ...
2061 * ...
2062 * @param my_parameter description of my_parameter
2063 * @return return value description
2064 */
2065int myfunc(int my_parameter)
2066...
2067</pre></td></tr></table>
2068<p>fprintf and printf are forbidden in libavformat and libavcodec,
2069please use av_log() instead.
2070</p>
2071<hr size="6">
2072<a name="Development-Policy"></a>
2073<a name="SEC34"></a>
2074<table cellpadding="1" cellspacing="1" border="0">
2075<tr><td valign="middle" align="left">[<a href="#SEC33" title="Previous section in reading order"> &lt; </a>]</td>
2076<td valign="middle" align="left">[<a href="#SEC35" title="Next section in reading order"> &gt; </a>]</td>
2077<td valign="middle" align="left"> &nbsp; </td>
2078<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
2079<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
2080<td valign="middle" align="left">[ &gt;&gt; ]</td>
2081<td valign="middle" align="left"> &nbsp; </td>
2082<td valign="middle" align="left"> &nbsp; </td>
2083<td valign="middle" align="left"> &nbsp; </td>
2084<td valign="middle" align="left"> &nbsp; </td>
2085<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
2086<td valign="middle" align="left">[Contents]</td>
2087<td valign="middle" align="left">[Index]</td>
2088<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
2089</tr></table>
2090<h2 class="section"> 7.4 Development Policy </h2>
2091
2092<ol>
2093<li>
2094 You must not commit code which breaks FFmpeg! (Meaning unfinished but
2095 enabled code which breaks compilation or compiles but does not work or
2096 breaks the regression tests)
2097 You can commit unfinished stuff (for testing etc), but it must be disabled
2098 (#ifdef etc) by default so it does not interfere with other developers'
2099 work.
2100</li><li>
2101 You don't have to over-test things. If it works for you, and you think it
2102 should work for others, then commit. If your code has problems
2103 (portability, triggers compiler bugs, unusual environment etc) they will be
2104 reported and eventually fixed.
2105</li><li>
2106 Do not commit unrelated changes together, split them into self-contained
2107 pieces.
2108</li><li>
2109 Do not change behavior of the program (renaming options etc) without
2110 first discussing it on the ffmpeg-devel mailing list. Do not remove
2111 functionality from the code. Just improve!
2112
2113<p> Note: Redundant code can be removed.
2114</p></li><li>
2115 Do not commit changes to the build system (Makefiles, configure script)
2116 which change behavior, defaults etc, without asking first. The same
2117 applies to compiler warning fixes, trivial looking fixes and to code
2118 maintained by other developers. We usually have a reason for doing things
2119 the way we do. Send your changes as patches to the ffmpeg-devel mailing
2120 list, and if the code maintainers say OK, you may commit. This does not
2121 apply to files you wrote and/or maintain.
2122</li><li>
2123 We refuse source indentation and other cosmetic changes if they are mixed
2124 with functional changes, such commits will be rejected and removed. Every
2125 developer has his own indentation style, you should not change it. Of course
2126 if you (re)write something, you can use your own style, even though we would
2127 prefer if the indentation throughout FFmpeg was consistent (Many projects
2128 force a given indentation style - we don't.). If you really need to make
2129 indentation changes (try to avoid this), separate them strictly from real
2130 changes.
2131
2132<p> NOTE: If you had to put if(){ .. } over a large (&gt; 5 lines) chunk of code,
2133 then either do NOT change the indentation of the inner part within (don't
2134 move it to the right)! or do so in a separate commit
2135</p></li><li>
2136 Always fill out the commit log message. Describe in a few lines what you
2137 changed and why. You can refer to mailing list postings if you fix a
2138 particular bug. Comments such as &quot;fixed!&quot; or &quot;Changed it.&quot; are unacceptable.
2139</li><li>
2140 If you apply a patch by someone else, include the name and email address in
2141 the log message. Since the ffmpeg-cvslog mailing list is publicly
2142 archived you should add some SPAM protection to the email address. Send an
2143 answer to ffmpeg-devel (or wherever you got the patch from) saying that
2144 you applied the patch.
2145</li><li>
2146 Do NOT commit to code actively maintained by others without permission. Send
2147 a patch to ffmpeg-devel instead.
2148</li><li>
2149 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
2150 are sent there and reviewed by all the other developers. Bugs and possible
2151 improvements or general questions regarding commits are discussed there. We
2152 expect you to react if problems with your code are uncovered.
2153</li><li>
2154 Update the documentation if you change behavior or add features. If you are
2155 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
2156 maintainer(s) will review and commit your stuff.
2157</li><li>
2158 Never write to unallocated memory, never write over the end of arrays,
2159 always check values read from some untrusted source before using them
2160 as array index or other risky things.
2161</li><li>
2162 Remember to check if you need to bump versions for the specific libav
2163 parts (libavutil, libavcodec, libavformat) you are changing. You need
2164 to change the version integer and the version string.
2165 Incrementing the first component means no backward compatibility to
2166 previous versions (e.g. removal of a function).
2167 Incrementing the second component means backward compatible change
2168 (e.g. addition of a function).
2169 Incrementing the third component means a noteworthy binary compatible
2170 change (e.g. encoder bug fix that matters for the decoder).
2171</li><li>
2172 If you add a new codec, remember to update the changelog, add it to
2173 the supported codecs table in the documentation and bump the second
2174 component of the <tt>`libavcodec'</tt> version number appropriately. If
2175 it has a fourcc, add it to <tt>`libavformat/avienc.c'</tt>, even if it
2176 is only a decoder.
2177</li></ol>
2178
2179<p>We think our rules are not too hard. If you have comments, contact us.
2180</p>
2181<p>Note, these rules are mostly borrowed from the MPlayer project.
2182</p>
2183<hr size="6">
2184<a name="SEC35"></a>
2185<table cellpadding="1" cellspacing="1" border="0">
2186<tr><td valign="middle" align="left">[<a href="#SEC34" title="Previous section in reading order"> &lt; </a>]</td>
2187<td valign="middle" align="left">[<a href="#SEC36" title="Next section in reading order"> &gt; </a>]</td>
2188<td valign="middle" align="left"> &nbsp; </td>
2189<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
2190<td valign="middle" align="left">[<a href="#SEC34" title="Up section"> Up </a>]</td>
2191<td valign="middle" align="left">[ &gt;&gt; ]</td>
2192<td valign="middle" align="left"> &nbsp; </td>
2193<td valign="middle" align="left"> &nbsp; </td>
2194<td valign="middle" align="left"> &nbsp; </td>
2195<td valign="middle" align="left"> &nbsp; </td>
2196<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
2197<td valign="middle" align="left">[Contents]</td>
2198<td valign="middle" align="left">[Index]</td>
2199<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
2200</tr></table>
2201<h3 class="subsection"> 7.4.1 Renaming/moving files or content of files </h3>
2202<p> You CANNOT do that. Post a request for such a change to the mailing list
2203 Do NOT remove &amp; readd a file - it will kill the changelog!!!!
2204</p>
2205<hr size="6">
2206<a name="SEC36"></a>
2207<table cellpadding="1" cellspacing="1" border="0">
2208<tr><td valign="middle" align="left">[<a href="#SEC35" title="Previous section in reading order"> &lt; </a>]</td>
2209<td valign="middle" align="left">[<a href="#SEC37" title="Next section in reading order"> &gt; </a>]</td>
2210<td valign="middle" align="left"> &nbsp; </td>
2211<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
2212<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
2213<td valign="middle" align="left">[ &gt;&gt; ]</td>
2214<td valign="middle" align="left"> &nbsp; </td>
2215<td valign="middle" align="left"> &nbsp; </td>
2216<td valign="middle" align="left"> &nbsp; </td>
2217<td valign="middle" align="left"> &nbsp; </td>
2218<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
2219<td valign="middle" align="left">[Contents]</td>
2220<td valign="middle" align="left">[Index]</td>
2221<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
2222</tr></table>
2223<h2 class="section"> 7.5 Submitting patches </h2>
2224
2225<p>First, (see section <a href="#SEC33">Coding Rules</a>) above if you didn't yet.
2226</p>
2227<p>When you submit your patch, try to send a unified diff (diff '-up'
2228option). I cannot read other diffs :-)
2229</p>
2230<p>Also please do not submit patches which contain several unrelated changes.
2231Split them into individual self-contained patches; this makes reviewing
2232them much easier.
2233</p>
2234<p>Run the regression tests before submitting a patch so that you can
2235verify that there are no big problems.
2236</p>
2237<p>Patches should be posted as base64 encoded attachments (or any other
2238encoding which ensures that the patch won't be trashed during
2239transmission) to the ffmpeg-devel mailing list, see
2240<a href="http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel">http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel</a>
2241</p>
2242<p>It also helps quite a bit if you tell us what the patch does (for example
2243'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
2244and has no lrint()')
2245</p>
2246<p>We reply to all submitted patches and either apply or reject with some
2247explanation why, but sometimes we are quite busy so it can take a week or two.
2248</p>
2249<hr size="6">
2250<a name="SEC37"></a>
2251<table cellpadding="1" cellspacing="1" border="0">
2252<tr><td valign="middle" align="left">[<a href="#SEC36" title="Previous section in reading order"> &lt; </a>]</td>
2253<td valign="middle" align="left">[ &gt; ]</td>
2254<td valign="middle" align="left"> &nbsp; </td>
2255<td valign="middle" align="left">[<a href="#SEC30" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
2256<td valign="middle" align="left">[<a href="#SEC30" title="Up section"> Up </a>]</td>
2257<td valign="middle" align="left">[ &gt;&gt; ]</td>
2258<td valign="middle" align="left"> &nbsp; </td>
2259<td valign="middle" align="left"> &nbsp; </td>
2260<td valign="middle" align="left"> &nbsp; </td>
2261<td valign="middle" align="left"> &nbsp; </td>
2262<td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
2263<td valign="middle" align="left">[Contents]</td>
2264<td valign="middle" align="left">[Index]</td>
2265<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
2266</tr></table>
2267<h2 class="section"> 7.6 Regression tests </h2>
2268
2269<p>Before submitting a patch (or committing to the repository), you should at least
2270test that you did not break anything.
2271</p>
2272<p>The regression tests build a synthetic video stream and a synthetic
2273audio stream. These are then encoded and decoded with all codecs or
2274formats. The CRC (or MD5) of each generated file is recorded in a
2275result file. A 'diff' is launched to compare the reference results and
2276the result file.
2277</p>
2278<p>The regression tests then go on to test the FFserver code with a
2279limited set of streams. It is important that this step runs correctly
2280as well.
2281</p>
2282<p>Run 'make test' to test all the codecs and formats.
2283</p>
2284<p>Run 'make fulltest' to test all the codecs, formats and FFserver.
2285</p>
2286<p>[Of course, some patches may change the results of the regression tests. In
2287this case, the reference results of the regression tests shall be modified
2288accordingly].
2289</p>
2290<hr size="6">
2291<a name="SEC_About"></a>
2292<table cellpadding="1" cellspacing="1" border="0">
2293<tr><td valign="middle" align="left">[<a href="#SEC1" title="Cover (top) of document">Top</a>]</td>
2294<td valign="middle" align="left">[Contents]</td>
2295<td valign="middle" align="left">[Index]</td>
2296<td valign="middle" align="left">[<a href="#SEC_About" title="About (help)"> ? </a>]</td>
2297</tr></table>
2298<h1>About This Document</h1>
2299<p>
2300 This document was generated on <i>June, 30 2006</i> using <a href="http://texi2html.cvshome.org/"><i>texi2html 1.76</i></a>.
2301</p>
2302<p>
2303 The buttons in the navigation panels have the following meaning:
2304</p>
2305<table border="1">
2306 <tr>
2307 <th> Button </th>
2308 <th> Name </th>
2309 <th> Go to </th>
2310 <th> From 1.2.3 go to</th>
2311 </tr>
2312 <tr>
2313 <td align="center"> [ &lt; ] </td>
2314 <td align="center">Back</td>
2315 <td>previous section in reading order</td>
2316 <td>1.2.2</td>
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2318 <tr>
2319 <td align="center"> [ &gt; ] </td>
2320 <td align="center">Forward</td>
2321 <td>next section in reading order</td>
2322 <td>1.2.4</td>
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2324 <tr>
2325 <td align="center"> [ &lt;&lt; ] </td>
2326 <td align="center">FastBack</td>
2327 <td>beginning of this chapter or previous chapter</td>
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2329 </tr>
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2332 <td align="center">Up</td>
2333 <td>up section</td>
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2353 </tr>
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2367
2368<p>
2369 where the <strong> Example </strong> assumes that the current position is at <strong> Subsubsection One-Two-Three </strong> of a document of the following structure:
2370</p>
2371
2372<ul>
2373 <li> 1. Section One
2374 <ul>
2375 <li>1.1 Subsection One-One
2376 <ul>
2377 <li>...</li>
2378 </ul>
2379 </li>
2380 <li>1.2 Subsection One-Two
2381 <ul>
2382 <li>1.2.1 Subsubsection One-Two-One</li>
2383 <li>1.2.2 Subsubsection One-Two-Two</li>
2384 <li>1.2.3 Subsubsection One-Two-Three &nbsp; &nbsp;
2385 <strong>&lt;== Current Position </strong></li>
2386 <li>1.2.4 Subsubsection One-Two-Four</li>
2387 </ul>
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2389 <li>1.3 Subsection One-Three
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2391 <li>...</li>
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2393 </li>
2394 <li>1.4 Subsection One-Four</li>
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2398
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