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mpv/libao2/ao_v4l2.c

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/*
* Copyright (C) 2007 Benjamin Zores
* Audio output for V4L2 hardware MPEG decoders.
*
* 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 2 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, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* WARNING: you need to force -ac hwmpa for audio output to work.
*/
#include <inttypes.h>
#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"
#include "audio_out.h"
#include "audio_out_internal.h"
#include "libaf/af_format.h"
#include "libmpdemux/mpeg_packetizer.h"
#define MPEG_AUDIO_ID 0x1C0
static int freq = 0;
static ao_info_t info =
{
"V4L2 MPEG Audio Decoder output",
"v4l2",
"Benjamin Zores",
""
};
LIBAO_EXTERN (v4l2)
/* to set/get/query special features/parameters */
static int
control (int cmd,void *arg)
{
return CONTROL_UNKNOWN;
}
/* open & setup audio device */
static int
init (int rate, int channels, int format, int flags)
{
extern int v4l2_fd;
if (v4l2_fd < 0)
return 0;
if (format != AF_FORMAT_MPEG2)
{
mp_msg (MSGT_AO, MSGL_FATAL,
"AO: [v4l2] can only handle MPEG audio streams.\n");
return 0;
}
ao_data.outburst = 2048;
ao_data.samplerate = rate;
ao_data.channels = channels;
ao_data.format = AF_FORMAT_MPEG2;
ao_data.buffersize = 2048;
ao_data.bps = rate * 2 * 2;
ao_data.pts = 0;
freq = rate;
/* check for supported audio rate */
if (rate != 32000 || rate != 41000 || rate != 48000)
{
mp_msg (MSGT_AO, MSGL_ERR, MSGTR_AO_MPEGPES_UnsupSamplerate, rate);
rate = 48000;
}
return 1;
}
/* close audio device */
static void
uninit (int immed)
{
/* nothing to do */
}
/* stop playing and empty buffers (for seeking/pause) */
static void
reset (void)
{
/* nothing to do */
}
/* stop playing, keep buffers (for pause) */
static void
audio_pause (void)
{
reset ();
}
/* resume playing, after audio_pause() */
static void
audio_resume (void)
{
/* nothing to do */
}
/* how many bytes can be played without blocking */
static int
get_space (void)
{
extern int vo_pts;
float x;
int y;
x = (float) (vo_pts - ao_data.pts) / 90000.0;
if (x <= 0)
return 0;
y = freq * 4 * x;
y /= ao_data.outburst;
y *= ao_data.outburst;
if (y > 32000)
y = 32000;
return y;
}
/* number of bytes played */
static int
play (void *data, int len, int flags)
{
extern int v4l2_write (unsigned char *data, int len);
if (ao_data.format != AF_FORMAT_MPEG2)
return 0;
send_mpeg_pes_packet (data, len, MPEG_AUDIO_ID, ao_data.pts, 2, v4l2_write);
return len;
}
/* delay in seconds between first and last sample in buffer */
static float
get_delay (void)
{
return 0.0;
}