mirror of
https://github.com/FFmpeg/FFmpeg.git
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313 lines
7.2 KiB
C
313 lines
7.2 KiB
C
/*
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* Linux audio play and grab interface
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* Copyright (c) 2000, 2001 Fabrice Bellard.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "avformat.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/soundcard.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/time.h>
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const char *audio_device = "/dev/dsp";
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#define AUDIO_BLOCK_SIZE 4096
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typedef struct {
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int fd;
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int sample_rate;
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int channels;
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int frame_size; /* in bytes ! */
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int codec_id;
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int flip_left : 1;
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UINT8 buffer[AUDIO_BLOCK_SIZE];
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int buffer_ptr;
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} AudioData;
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static int audio_open(AudioData *s, int is_output)
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{
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int audio_fd;
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int tmp, err;
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char *flip = getenv("AUDIO_FLIP_LEFT");
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/* open linux audio device */
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if (is_output)
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audio_fd = open(audio_device, O_WRONLY);
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else
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audio_fd = open(audio_device, O_RDONLY);
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if (audio_fd < 0) {
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perror(audio_device);
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return -EIO;
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}
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if (flip && *flip == '1') {
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s->flip_left = 1;
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}
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/* non blocking mode */
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fcntl(audio_fd, F_SETFL, O_NONBLOCK);
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s->frame_size = AUDIO_BLOCK_SIZE;
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#if 0
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tmp = (NB_FRAGMENTS << 16) | FRAGMENT_BITS;
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err = ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &tmp);
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if (err < 0) {
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perror("SNDCTL_DSP_SETFRAGMENT");
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}
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#endif
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/* select format : favour native format */
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err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
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#ifdef WORDS_BIGENDIAN
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if (tmp & AFMT_S16_BE) {
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tmp = AFMT_S16_BE;
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} else if (tmp & AFMT_S16_LE) {
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tmp = AFMT_S16_LE;
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} else {
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tmp = 0;
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}
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#else
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if (tmp & AFMT_S16_LE) {
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tmp = AFMT_S16_LE;
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} else if (tmp & AFMT_S16_BE) {
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tmp = AFMT_S16_BE;
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} else {
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tmp = 0;
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}
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#endif
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switch(tmp) {
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case AFMT_S16_LE:
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s->codec_id = CODEC_ID_PCM_S16LE;
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break;
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case AFMT_S16_BE:
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s->codec_id = CODEC_ID_PCM_S16BE;
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break;
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default:
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fprintf(stderr, "Soundcard does not support 16 bit sample format\n");
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close(audio_fd);
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return -EIO;
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}
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err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
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if (err < 0) {
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perror("SNDCTL_DSP_SETFMT");
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goto fail;
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}
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tmp = (s->channels == 2);
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err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
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if (err < 0) {
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perror("SNDCTL_DSP_STEREO");
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goto fail;
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}
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if (tmp)
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s->channels = 2;
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tmp = s->sample_rate;
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err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
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if (err < 0) {
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perror("SNDCTL_DSP_SPEED");
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goto fail;
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}
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s->sample_rate = tmp; /* store real sample rate */
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s->fd = audio_fd;
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return 0;
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fail:
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close(audio_fd);
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return -EIO;
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}
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static int audio_close(AudioData *s)
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{
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close(s->fd);
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return 0;
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}
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/* sound output support */
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static int audio_write_header(AVFormatContext *s1)
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{
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AudioData *s = s1->priv_data;
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AVStream *st;
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int ret;
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st = s1->streams[0];
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s->sample_rate = st->codec.sample_rate;
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s->channels = st->codec.channels;
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ret = audio_open(s, 1);
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if (ret < 0) {
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return -EIO;
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} else {
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return 0;
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}
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}
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static int audio_write_packet(AVFormatContext *s1, int stream_index,
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UINT8 *buf, int size, int force_pts)
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{
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AudioData *s = s1->priv_data;
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int len, ret;
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while (size > 0) {
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len = AUDIO_BLOCK_SIZE - s->buffer_ptr;
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if (len > size)
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len = size;
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memcpy(s->buffer + s->buffer_ptr, buf, len);
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s->buffer_ptr += len;
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if (s->buffer_ptr >= AUDIO_BLOCK_SIZE) {
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for(;;) {
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ret = write(s->fd, s->buffer, AUDIO_BLOCK_SIZE);
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if (ret != 0)
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break;
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if (ret < 0 && (errno != EAGAIN && errno != EINTR))
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return -EIO;
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}
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s->buffer_ptr = 0;
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}
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buf += len;
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size -= len;
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}
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return 0;
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}
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static int audio_write_trailer(AVFormatContext *s1)
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{
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AudioData *s = s1->priv_data;
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audio_close(s);
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return 0;
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}
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/* grab support */
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static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
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{
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AudioData *s = s1->priv_data;
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AVStream *st;
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int ret;
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if (!ap || ap->sample_rate <= 0 || ap->channels <= 0)
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return -1;
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st = av_new_stream(s1, 0);
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if (!st) {
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return -ENOMEM;
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}
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s->sample_rate = ap->sample_rate;
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s->channels = ap->channels;
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ret = audio_open(s, 0);
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if (ret < 0) {
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av_free(st);
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return -EIO;
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} else {
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/* take real parameters */
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st->codec.codec_type = CODEC_TYPE_AUDIO;
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st->codec.codec_id = s->codec_id;
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st->codec.sample_rate = s->sample_rate;
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st->codec.channels = s->channels;
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return 0;
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}
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}
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static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
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{
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AudioData *s = s1->priv_data;
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int ret;
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if (av_new_packet(pkt, s->frame_size) < 0)
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return -EIO;
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for(;;) {
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ret = read(s->fd, pkt->data, pkt->size);
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if (ret > 0)
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break;
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if (ret == -1 && (errno == EAGAIN || errno == EINTR)) {
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av_free_packet(pkt);
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pkt->size = 0;
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return 0;
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}
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if (!(ret == 0 || (ret == -1 && (errno == EAGAIN || errno == EINTR)))) {
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av_free_packet(pkt);
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return -EIO;
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}
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}
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pkt->size = ret;
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if (s->flip_left && s->channels == 2) {
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int i;
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short *p = (short *) pkt->data;
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for (i = 0; i < ret; i += 4) {
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*p = ~*p;
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p += 2;
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}
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}
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return 0;
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}
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static int audio_read_close(AVFormatContext *s1)
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{
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AudioData *s = s1->priv_data;
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audio_close(s);
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return 0;
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}
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AVInputFormat audio_in_format = {
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"audio_device",
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"audio grab and output",
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sizeof(AudioData),
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NULL,
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audio_read_header,
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audio_read_packet,
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audio_read_close,
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.flags = AVFMT_NOFILE,
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};
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AVOutputFormat audio_out_format = {
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"audio_device",
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"audio grab and output",
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"",
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"",
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sizeof(AudioData),
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/* XXX: we make the assumption that the soundcard accepts this format */
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/* XXX: find better solution with "preinit" method, needed also in
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other formats */
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#ifdef WORDS_BIGENDIAN
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CODEC_ID_PCM_S16BE,
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#else
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CODEC_ID_PCM_S16LE,
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#endif
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CODEC_ID_NONE,
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audio_write_header,
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audio_write_packet,
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audio_write_trailer,
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.flags = AVFMT_NOFILE,
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};
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int audio_init(void)
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{
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av_register_input_format(&audio_in_format);
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av_register_output_format(&audio_out_format);
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return 0;
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}
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