source: vbox/trunk/src/VBox/RDP/client-1.8.3/rdpsnd_libao.c@ 55121

/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Sound Channel Process Functions - libao-driver
   Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 2003-2008
   Copyright (C) GuoJunBo <guojunbo@ict.ac.cn> 2003
   Copyright (C) Michael Gernoth <mike@zerfleddert.de> 2005-2008
   Copyright (C) 2013 Henrik Andersson

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "rdesktop.h"
#include "rdpsnd.h"
#include "rdpsnd_dsp.h"
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ao/ao.h>
#include <sys/time.h>

#define WAVEOUTLEN      16

static ao_device *o_device = NULL;
static int default_driver;
static RD_BOOL reopened;
static char *libao_device = NULL;

void libao_play(void);

void
libao_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv)
{
        /* We need to be called rather often... */
        if (o_device != NULL && !rdpsnd_queue_empty())
                FD_SET(0, wfds);
}

void
libao_check_fds(fd_set * rfds, fd_set * wfds)
{
        if (o_device == NULL)
                return;

        if (!rdpsnd_queue_empty())
                libao_play();
}

RD_BOOL
libao_open(void)
{
        ao_sample_format format;

        ao_initialize();

        if (libao_device)
        {
                default_driver = ao_driver_id(libao_device);
        }
        else
        {
                default_driver = ao_default_driver_id();
        }

        memset(&format, 0, sizeof(format));
        format.bits = 16;
        format.channels = 2;
        format.rate = 44100;
        format.byte_format = AO_FMT_NATIVE;

        o_device = ao_open_live(default_driver, &format, NULL);
        if (o_device == NULL)
        {
                return False;
        }

        reopened = True;

        return True;
}

void
libao_close(void)
{
        /* Ack all remaining packets */
        while (!rdpsnd_queue_empty())
        {
                rdpsnd_queue_next(0);
        }

        if (o_device != NULL)
                ao_close(o_device);

        o_device = NULL;

        ao_shutdown();
}

RD_BOOL
libao_set_format(RD_WAVEFORMATEX * pwfx)
{
        ao_sample_format format;

        memset(&format, 0, sizeof(format));
        format.bits = pwfx->wBitsPerSample;
        format.channels = pwfx->nChannels;
        format.rate = 44100;
        format.byte_format = AO_FMT_NATIVE;

        if (o_device != NULL)
                ao_close(o_device);

        o_device = ao_open_live(default_driver, &format, NULL);
        if (o_device == NULL)
        {
                return False;
        }

        if (rdpsnd_dsp_resample_set(44100, pwfx->wBitsPerSample, pwfx->nChannels) == False)
        {
                return False;
        }

        reopened = True;

        return True;
}

void
libao_play(void)
{
        struct audio_packet *packet;
        STREAM out;
        int len;
        static long prev_s, prev_us;
        unsigned int duration;
        struct timeval tv;
        int next_tick;

        if (reopened)
        {
                reopened = False;
                gettimeofday(&tv, NULL);
                prev_s = tv.tv_sec;
                prev_us = tv.tv_usec;
        }

        /* We shouldn't be called if the queue is empty, but still */
        if (rdpsnd_queue_empty())
                return;

        packet = rdpsnd_queue_current_packet();
        out = &packet->s;

        next_tick = rdpsnd_queue_next_tick();

        len = (WAVEOUTLEN > (out->end - out->p)) ? (out->end - out->p) : WAVEOUTLEN;
        ao_play(o_device, (char *) out->p, len);
        out->p += len;

        gettimeofday(&tv, NULL);

        duration = ((tv.tv_sec - prev_s) * 1000000 + (tv.tv_usec - prev_us)) / 1000;

        if (packet->tick > next_tick)
                next_tick += 65536;

        if ((out->p == out->end) || duration > next_tick - packet->tick + 500)
        {
                unsigned int delay_us;

                prev_s = tv.tv_sec;
                prev_us = tv.tv_usec;

                if (abs((next_tick - packet->tick) - duration) > 20)
                {
                        DEBUG(("duration: %d, calc: %d, ", duration, next_tick - packet->tick));
                        DEBUG(("last: %d, is: %d, should: %d\n", packet->tick,
                               (packet->tick + duration) % 65536, next_tick % 65536));
                }

                delay_us = ((out->size / 4) * (1000000 / 44100));

                rdpsnd_queue_next(delay_us);
        }
}

struct audio_driver *
libao_register(char *options)
{
        static struct audio_driver libao_driver;

        memset(&libao_driver, 0, sizeof(libao_driver));

        libao_driver.name = "libao";
        libao_driver.description = "libao output driver, default device: system dependent";

        libao_driver.add_fds = libao_add_fds;
        libao_driver.check_fds = libao_check_fds;

        libao_driver.wave_out_open = libao_open;
        libao_driver.wave_out_close = libao_close;
        libao_driver.wave_out_format_supported = rdpsnd_dsp_resample_supported;
        libao_driver.wave_out_set_format = libao_set_format;
        libao_driver.wave_out_volume = rdpsnd_dsp_softvol_set;

        libao_driver.need_byteswap_on_be = 1;
        libao_driver.need_resampling = 1;

        if (options)
        {
                libao_device = xstrdup(options);
        }

        return &libao_driver;
}