| 1 | /*
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| 2 | * Animated GIF encoder
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| 3 | * Copyright (c) 2000 Fabrice Bellard.
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| 4 | *
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| 5 | * This library is free software; you can redistribute it and/or
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| 6 | * modify it under the terms of the GNU Lesser General Public
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| 7 | * License as published by the Free Software Foundation; either
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| 8 | * version 2 of the License, or (at your option) any later version.
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| 9 | *
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| 10 | * This library is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 13 | * Lesser General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU Lesser General Public
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| 16 | * License along with this library; if not, write to the Free Software
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| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 18 | */
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| 19 |
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| 20 | /*
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| 21 | * First version by Francois Revol revol@free.fr
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| 22 | *
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| 23 | * Features and limitations:
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| 24 | * - currently no compression is performed,
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| 25 | * in fact the size of the data is 9/8 the size of the image in 8bpp
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| 26 | * - uses only a global standard palette
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| 27 | * - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS).
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| 28 | *
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| 29 | * Reference documents:
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| 30 | * http://www.goice.co.jp/member/mo/formats/gif.html
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| 31 | * http://astronomy.swin.edu.au/pbourke/dataformats/gif/
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| 32 | * http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt
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| 33 | *
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| 34 | * this url claims to have an LZW algorithm not covered by Unisys patent:
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| 35 | * http://www.msg.net/utility/whirlgif/gifencod.html
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| 36 | * could help reduce the size of the files _a lot_...
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| 37 | * some sites mentions an RLE type compression also.
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| 38 | */
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| 39 |
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| 40 | #include "avformat.h"
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| 41 | #include "bitstream.h"
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| 42 |
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| 43 | /* bitstream minipacket size */
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| 44 | #define GIF_CHUNKS 100
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| 45 |
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| 46 | /* slows down the decoding (and some browsers don't like it) */
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| 47 | /* update on the 'some browsers don't like it issue from above: this was probably due to missing 'Data Sub-block Terminator' (byte 19) in the app_header */
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| 48 | #define GIF_ADD_APP_HEADER // required to enable looping of animated gif
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| 49 |
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| 50 | typedef struct {
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| 51 | unsigned char r;
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| 52 | unsigned char g;
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| 53 | unsigned char b;
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| 54 | } rgb_triplet;
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| 55 |
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| 56 | /* we use the standard 216 color palette */
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| 57 |
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| 58 | /* this script was used to create the palette:
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| 59 | * for r in 00 33 66 99 cc ff; do for g in 00 33 66 99 cc ff; do echo -n " "; for b in 00 33 66 99 cc ff; do
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| 60 | * echo -n "{ 0x$r, 0x$g, 0x$b }, "; done; echo ""; done; done
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| 61 | */
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| 62 |
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| 63 | static const rgb_triplet gif_clut[216] = {
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| 64 | { 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff },
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| 65 | { 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff },
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| 66 | { 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff },
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| 67 | { 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff },
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| 68 | { 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff },
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| 69 | { 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff },
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| 70 | { 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff },
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| 71 | { 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff },
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| 72 | { 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff },
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| 73 | { 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff },
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| 74 | { 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff },
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| 75 | { 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff },
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| 76 | { 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff },
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| 77 | { 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff },
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| 78 | { 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff },
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| 79 | { 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff },
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| 80 | { 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff },
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| 81 | { 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff },
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| 82 | { 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff },
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| 83 | { 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff },
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| 84 | { 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff },
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| 85 | { 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff },
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| 86 | { 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff },
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| 87 | { 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff },
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| 88 | { 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff },
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| 89 | { 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff },
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| 90 | { 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff },
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| 91 | { 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff },
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| 92 | { 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff },
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| 93 | { 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff },
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| 94 | { 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff },
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| 95 | { 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff },
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| 96 | { 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff },
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| 97 | { 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff },
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| 98 | { 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff },
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| 99 | { 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff },
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| 100 | };
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| 101 |
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| 102 | /* The GIF format uses reversed order for bitstreams... */
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| 103 | /* at least they don't use PDP_ENDIAN :) */
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| 104 | /* so we 'extend' PutBitContext. hmmm, OOP :) */
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| 105 | /* seems this thing changed slightly since I wrote it... */
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| 106 |
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| 107 | #ifdef ALT_BITSTREAM_WRITER
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| 108 | # error no ALT_BITSTREAM_WRITER support for now
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| 109 | #endif
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| 110 |
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| 111 | static void gif_put_bits_rev(PutBitContext *s, int n, unsigned int value)
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| 112 | {
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| 113 | unsigned int bit_buf;
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| 114 | int bit_cnt;
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| 115 |
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| 116 | // printf("put_bits=%d %x\n", n, value);
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| 117 | assert(n == 32 || value < (1U << n));
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| 118 |
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| 119 | bit_buf = s->bit_buf;
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| 120 | bit_cnt = 32 - s->bit_left; /* XXX:lazyness... was = s->bit_cnt; */
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| 121 |
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| 122 | // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
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| 123 | /* XXX: optimize */
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| 124 | if (n < (32-bit_cnt)) {
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| 125 | bit_buf |= value << (bit_cnt);
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| 126 | bit_cnt+=n;
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| 127 | } else {
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| 128 | bit_buf |= value << (bit_cnt);
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| 129 |
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| 130 | *s->buf_ptr = bit_buf & 0xff;
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| 131 | s->buf_ptr[1] = (bit_buf >> 8) & 0xff;
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| 132 | s->buf_ptr[2] = (bit_buf >> 16) & 0xff;
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| 133 | s->buf_ptr[3] = (bit_buf >> 24) & 0xff;
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| 134 |
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| 135 | //printf("bitbuf = %08x\n", bit_buf);
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| 136 | s->buf_ptr+=4;
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| 137 | if (s->buf_ptr >= s->buf_end)
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| 138 | puts("bit buffer overflow !!"); // should never happen ! who got rid of the callback ???
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| 139 | // flush_buffer_rev(s);
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| 140 | bit_cnt=bit_cnt + n - 32;
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| 141 | if (bit_cnt == 0) {
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| 142 | bit_buf = 0;
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| 143 | } else {
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| 144 | bit_buf = value >> (n - bit_cnt);
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| 145 | }
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| 146 | }
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| 147 |
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| 148 | s->bit_buf = bit_buf;
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| 149 | s->bit_left = 32 - bit_cnt;
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| 150 | }
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| 151 |
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| 152 | /* pad the end of the output stream with zeros */
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| 153 | static void gif_flush_put_bits_rev(PutBitContext *s)
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| 154 | {
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| 155 | while (s->bit_left < 32) {
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| 156 | /* XXX: should test end of buffer */
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| 157 | *s->buf_ptr++=s->bit_buf & 0xff;
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| 158 | s->bit_buf>>=8;
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| 159 | s->bit_left+=8;
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| 160 | }
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| 161 | // flush_buffer_rev(s);
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| 162 | s->bit_left=32;
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| 163 | s->bit_buf=0;
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| 164 | }
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| 165 |
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| 166 | /* !RevPutBitContext */
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| 167 |
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| 168 | /* GIF header */
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| 169 | static int gif_image_write_header(ByteIOContext *pb,
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| 170 | int width, int height, int loop_count,
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| 171 | uint32_t *palette)
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| 172 | {
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| 173 | int i;
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| 174 | unsigned int v;
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| 175 |
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| 176 | put_tag(pb, "GIF");
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| 177 | put_tag(pb, "89a");
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| 178 | put_le16(pb, width);
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| 179 | put_le16(pb, height);
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| 180 |
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| 181 | put_byte(pb, 0xf7); /* flags: global clut, 256 entries */
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| 182 | put_byte(pb, 0x1f); /* background color index */
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| 183 | put_byte(pb, 0); /* aspect ratio */
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| 184 |
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| 185 | /* the global palette */
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| 186 | if (!palette) {
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| 187 | put_buffer(pb, (const unsigned char *)gif_clut, 216*3);
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| 188 | for(i=0;i<((256-216)*3);i++)
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| 189 | put_byte(pb, 0);
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| 190 | } else {
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| 191 | for(i=0;i<256;i++) {
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| 192 | v = palette[i];
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| 193 | put_byte(pb, (v >> 16) & 0xff);
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| 194 | put_byte(pb, (v >> 8) & 0xff);
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| 195 | put_byte(pb, (v) & 0xff);
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| 196 | }
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| 197 | }
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| 198 |
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| 199 | /* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated gif
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| 200 | see http://members.aol.com/royalef/gifabout.htm#net-extension
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| 201 |
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| 202 | byte 1 : 33 (hex 0x21) GIF Extension code
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| 203 | byte 2 : 255 (hex 0xFF) Application Extension Label
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| 204 | byte 3 : 11 (hex (0x0B) Length of Application Block
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| 205 | (eleven bytes of data to follow)
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| 206 | bytes 4 to 11 : "NETSCAPE"
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| 207 | bytes 12 to 14 : "2.0"
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| 208 | byte 15 : 3 (hex 0x03) Length of Data Sub-Block
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| 209 | (three bytes of data to follow)
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| 210 | byte 16 : 1 (hex 0x01)
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| 211 | bytes 17 to 18 : 0 to 65535, an unsigned integer in
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| 212 | lo-hi byte format. This indicate the
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| 213 | number of iterations the loop should
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| 214 | be executed.
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| 215 | bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator
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| 216 | */
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| 217 |
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| 218 | /* application extension header */
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| 219 | #ifdef GIF_ADD_APP_HEADER
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| 220 | if (loop_count >= 0 && loop_count <= 65535) {
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| 221 | put_byte(pb, 0x21);
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| 222 | put_byte(pb, 0xff);
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| 223 | put_byte(pb, 0x0b);
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| 224 | put_tag(pb, "NETSCAPE2.0"); // bytes 4 to 14
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| 225 | put_byte(pb, 0x03); // byte 15
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| 226 | put_byte(pb, 0x01); // byte 16
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| 227 | put_le16(pb, (uint16_t)loop_count);
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| 228 | put_byte(pb, 0x00); // byte 19
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| 229 | }
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| 230 | #endif
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| 231 | return 0;
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| 232 | }
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| 233 |
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| 234 | /* this is maybe slow, but allows for extensions */
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| 235 | static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b)
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| 236 | {
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| 237 | return ((((r)/47)%6)*6*6+(((g)/47)%6)*6+(((b)/47)%6));
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| 238 | }
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| 239 |
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| 240 |
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| 241 | static int gif_image_write_image(ByteIOContext *pb,
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| 242 | int x1, int y1, int width, int height,
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| 243 | const uint8_t *buf, int linesize, int pix_fmt)
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| 244 | {
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| 245 | PutBitContext p;
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| 246 | uint8_t buffer[200]; /* 100 * 9 / 8 = 113 */
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| 247 | int i, left, w, v;
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| 248 | const uint8_t *ptr;
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| 249 | /* image block */
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| 250 |
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| 251 | put_byte(pb, 0x2c);
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| 252 | put_le16(pb, x1);
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| 253 | put_le16(pb, y1);
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| 254 | put_le16(pb, width);
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| 255 | put_le16(pb, height);
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| 256 | put_byte(pb, 0x00); /* flags */
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| 257 | /* no local clut */
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| 258 |
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| 259 | put_byte(pb, 0x08);
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| 260 |
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| 261 | left= width * height;
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| 262 |
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| 263 | init_put_bits(&p, buffer, 130);
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| 264 |
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| 265 | /*
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| 266 | * the thing here is the bitstream is written as little packets, with a size byte before
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| 267 | * but it's still the same bitstream between packets (no flush !)
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| 268 | */
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| 269 | ptr = buf;
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| 270 | w = width;
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| 271 | while(left>0) {
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| 272 |
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| 273 | gif_put_bits_rev(&p, 9, 0x0100); /* clear code */
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| 274 |
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| 275 | for(i=(left<GIF_CHUNKS)?left:GIF_CHUNKS;i;i--) {
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| 276 | if (pix_fmt == PIX_FMT_RGB24) {
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| 277 | v = gif_clut_index(ptr[0], ptr[1], ptr[2]);
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| 278 | ptr+=3;
|
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| 279 | } else {
|
|---|
| 280 | v = *ptr++;
|
|---|
| 281 | }
|
|---|
| 282 | gif_put_bits_rev(&p, 9, v);
|
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| 283 | if (--w == 0) {
|
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| 284 | w = width;
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| 285 | buf += linesize;
|
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| 286 | ptr = buf;
|
|---|
| 287 | }
|
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| 288 | }
|
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| 289 |
|
|---|
| 290 | if(left<=GIF_CHUNKS) {
|
|---|
| 291 | gif_put_bits_rev(&p, 9, 0x101); /* end of stream */
|
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| 292 | gif_flush_put_bits_rev(&p);
|
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| 293 | }
|
|---|
| 294 | if(pbBufPtr(&p) - p.buf > 0) {
|
|---|
| 295 | put_byte(pb, pbBufPtr(&p) - p.buf); /* byte count of the packet */
|
|---|
| 296 | put_buffer(pb, p.buf, pbBufPtr(&p) - p.buf); /* the actual buffer */
|
|---|
| 297 | p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */
|
|---|
| 298 | }
|
|---|
| 299 | left-=GIF_CHUNKS;
|
|---|
| 300 | }
|
|---|
| 301 | put_byte(pb, 0x00); /* end of image block */
|
|---|
| 302 |
|
|---|
| 303 | return 0;
|
|---|
| 304 | }
|
|---|
| 305 |
|
|---|
| 306 | typedef struct {
|
|---|
| 307 | int64_t time, file_time;
|
|---|
| 308 | uint8_t buffer[100]; /* data chunks */
|
|---|
| 309 | } GIFContext;
|
|---|
| 310 |
|
|---|
| 311 | static int gif_write_header(AVFormatContext *s)
|
|---|
| 312 | {
|
|---|
| 313 | GIFContext *gif = s->priv_data;
|
|---|
| 314 | ByteIOContext *pb = &s->pb;
|
|---|
| 315 | AVCodecContext *enc, *video_enc;
|
|---|
| 316 | int i, width, height, loop_count /*, rate*/;
|
|---|
| 317 |
|
|---|
| 318 | /* XXX: do we reject audio streams or just ignore them ?
|
|---|
| 319 | if(s->nb_streams > 1)
|
|---|
| 320 | return -1;
|
|---|
| 321 | */
|
|---|
| 322 | gif->time = 0;
|
|---|
| 323 | gif->file_time = 0;
|
|---|
| 324 |
|
|---|
| 325 | video_enc = NULL;
|
|---|
| 326 | for(i=0;i<s->nb_streams;i++) {
|
|---|
| 327 | enc = s->streams[i]->codec;
|
|---|
| 328 | if (enc->codec_type != CODEC_TYPE_AUDIO)
|
|---|
| 329 | video_enc = enc;
|
|---|
| 330 | }
|
|---|
| 331 |
|
|---|
| 332 | if (!video_enc) {
|
|---|
| 333 | av_free(gif);
|
|---|
| 334 | return -1;
|
|---|
| 335 | } else {
|
|---|
| 336 | width = video_enc->width;
|
|---|
| 337 | height = video_enc->height;
|
|---|
| 338 | loop_count = s->loop_output;
|
|---|
| 339 | // rate = video_enc->time_base.den;
|
|---|
| 340 | }
|
|---|
| 341 |
|
|---|
| 342 | /* XXX: is it allowed ? seems to work so far... */
|
|---|
| 343 | video_enc->pix_fmt = PIX_FMT_RGB24;
|
|---|
| 344 |
|
|---|
| 345 | gif_image_write_header(pb, width, height, loop_count, NULL);
|
|---|
| 346 |
|
|---|
| 347 | put_flush_packet(&s->pb);
|
|---|
| 348 | return 0;
|
|---|
| 349 | }
|
|---|
| 350 |
|
|---|
| 351 | static int gif_write_video(AVFormatContext *s,
|
|---|
| 352 | AVCodecContext *enc, const uint8_t *buf, int size)
|
|---|
| 353 | {
|
|---|
| 354 | ByteIOContext *pb = &s->pb;
|
|---|
| 355 | GIFContext *gif = s->priv_data;
|
|---|
| 356 | int jiffies;
|
|---|
| 357 | int64_t delay;
|
|---|
| 358 |
|
|---|
| 359 | /* graphic control extension block */
|
|---|
| 360 | put_byte(pb, 0x21);
|
|---|
| 361 | put_byte(pb, 0xf9);
|
|---|
| 362 | put_byte(pb, 0x04); /* block size */
|
|---|
| 363 | put_byte(pb, 0x04); /* flags */
|
|---|
| 364 |
|
|---|
| 365 | /* 1 jiffy is 1/70 s */
|
|---|
| 366 | /* the delay_time field indicates the number of jiffies - 1 */
|
|---|
| 367 | delay = gif->file_time - gif->time;
|
|---|
| 368 |
|
|---|
| 369 | /* XXX: should use delay, in order to be more accurate */
|
|---|
| 370 | /* instead of using the same rounded value each time */
|
|---|
| 371 | /* XXX: don't even remember if I really use it for now */
|
|---|
| 372 | jiffies = (70*enc->time_base.num/enc->time_base.den) - 1;
|
|---|
| 373 |
|
|---|
| 374 | put_le16(pb, jiffies);
|
|---|
| 375 |
|
|---|
| 376 | put_byte(pb, 0x1f); /* transparent color index */
|
|---|
| 377 | put_byte(pb, 0x00);
|
|---|
| 378 |
|
|---|
| 379 | gif_image_write_image(pb, 0, 0, enc->width, enc->height,
|
|---|
| 380 | buf, enc->width * 3, PIX_FMT_RGB24);
|
|---|
| 381 |
|
|---|
| 382 | put_flush_packet(&s->pb);
|
|---|
| 383 | return 0;
|
|---|
| 384 | }
|
|---|
| 385 |
|
|---|
| 386 | static int gif_write_packet(AVFormatContext *s, AVPacket *pkt)
|
|---|
| 387 | {
|
|---|
| 388 | AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
|
|---|
| 389 | if (codec->codec_type == CODEC_TYPE_AUDIO)
|
|---|
| 390 | return 0; /* just ignore audio */
|
|---|
| 391 | else
|
|---|
| 392 | return gif_write_video(s, codec, pkt->data, pkt->size);
|
|---|
| 393 | }
|
|---|
| 394 |
|
|---|
| 395 | static int gif_write_trailer(AVFormatContext *s)
|
|---|
| 396 | {
|
|---|
| 397 | ByteIOContext *pb = &s->pb;
|
|---|
| 398 |
|
|---|
| 399 | put_byte(pb, 0x3b);
|
|---|
| 400 | put_flush_packet(&s->pb);
|
|---|
| 401 | return 0;
|
|---|
| 402 | }
|
|---|
| 403 |
|
|---|
| 404 | /* better than nothing gif image writer */
|
|---|
| 405 | int gif_write(ByteIOContext *pb, AVImageInfo *info)
|
|---|
| 406 | {
|
|---|
| 407 | gif_image_write_header(pb, info->width, info->height, AVFMT_NOOUTPUTLOOP,
|
|---|
| 408 | (uint32_t *)info->pict.data[1]);
|
|---|
| 409 | gif_image_write_image(pb, 0, 0, info->width, info->height,
|
|---|
| 410 | info->pict.data[0], info->pict.linesize[0],
|
|---|
| 411 | PIX_FMT_PAL8);
|
|---|
| 412 | put_byte(pb, 0x3b);
|
|---|
| 413 | put_flush_packet(pb);
|
|---|
| 414 | return 0;
|
|---|
| 415 | }
|
|---|
| 416 |
|
|---|
| 417 | static AVOutputFormat gif_muxer = {
|
|---|
| 418 | "gif",
|
|---|
| 419 | "GIF Animation",
|
|---|
| 420 | "image/gif",
|
|---|
| 421 | "gif",
|
|---|
| 422 | sizeof(GIFContext),
|
|---|
| 423 | CODEC_ID_NONE,
|
|---|
| 424 | CODEC_ID_RAWVIDEO,
|
|---|
| 425 | gif_write_header,
|
|---|
| 426 | gif_write_packet,
|
|---|
| 427 | gif_write_trailer,
|
|---|
| 428 | };
|
|---|
| 429 |
|
|---|
| 430 | extern AVInputFormat gif_demuxer;
|
|---|
| 431 |
|
|---|
| 432 | int gif_init(void)
|
|---|
| 433 | {
|
|---|
| 434 | av_register_output_format(&gif_muxer);
|
|---|
| 435 | av_register_input_format(&gif_demuxer);
|
|---|
| 436 | return 0;
|
|---|
| 437 | }
|
|---|
