FFmpeg  4.0
oss.c
Go to the documentation of this file.
1 /*
2  * Linux audio play and grab interface
3  * Copyright (c) 2000, 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "config.h"
23 
24 #include <string.h>
25 
26 #if HAVE_UNISTD_H
27 #include <unistd.h>
28 #endif
29 #include <fcntl.h>
30 #include <sys/ioctl.h>
31 #include <sys/soundcard.h>
32 
33 #include "libavutil/log.h"
34 
35 #include "libavcodec/avcodec.h"
36 #include "avdevice.h"
37 
38 #include "oss.h"
39 
40 int ff_oss_audio_open(AVFormatContext *s1, int is_output,
41  const char *audio_device)
42 {
43  OSSAudioData *s = s1->priv_data;
44  int audio_fd;
45  int tmp, err;
46  char *flip = getenv("AUDIO_FLIP_LEFT");
47 
48  if (is_output)
49  audio_fd = avpriv_open(audio_device, O_WRONLY);
50  else
51  audio_fd = avpriv_open(audio_device, O_RDONLY);
52  if (audio_fd < 0) {
53  av_log(s1, AV_LOG_ERROR, "%s: %s\n", audio_device, av_err2str(AVERROR(errno)));
54  return AVERROR(EIO);
55  }
56 
57  if (flip && *flip == '1') {
58  s->flip_left = 1;
59  }
60 
61  /* non blocking mode */
62  if (!is_output) {
63  if (fcntl(audio_fd, F_SETFL, O_NONBLOCK) < 0) {
64  av_log(s1, AV_LOG_WARNING, "%s: Could not enable non block mode (%s)\n", audio_device, av_err2str(AVERROR(errno)));
65  }
66  }
67 
69 
70 #define CHECK_IOCTL_ERROR(event) \
71  if (err < 0) { \
72  av_log(s1, AV_LOG_ERROR, #event ": %s\n", av_err2str(AVERROR(errno)));\
73  goto fail; \
74  }
75 
76  /* select format : favour native format
77  * We don't CHECK_IOCTL_ERROR here because even if failed OSS still may be
78  * usable. If OSS is not usable the SNDCTL_DSP_SETFMTS later is going to
79  * fail anyway. */
80  err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
81  if (err < 0) {
82  av_log(s1, AV_LOG_WARNING, "SNDCTL_DSP_GETFMTS: %s\n", av_err2str(AVERROR(errno)));
83  }
84 
85 #if HAVE_BIGENDIAN
86  if (tmp & AFMT_S16_BE) {
87  tmp = AFMT_S16_BE;
88  } else if (tmp & AFMT_S16_LE) {
89  tmp = AFMT_S16_LE;
90  } else {
91  tmp = 0;
92  }
93 #else
94  if (tmp & AFMT_S16_LE) {
95  tmp = AFMT_S16_LE;
96  } else if (tmp & AFMT_S16_BE) {
97  tmp = AFMT_S16_BE;
98  } else {
99  tmp = 0;
100  }
101 #endif
102 
103  switch(tmp) {
104  case AFMT_S16_LE:
106  break;
107  case AFMT_S16_BE:
109  break;
110  default:
111  av_log(s1, AV_LOG_ERROR, "Soundcard does not support 16 bit sample format\n");
112  close(audio_fd);
113  return AVERROR(EIO);
114  }
115  err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
116  CHECK_IOCTL_ERROR(SNDCTL_DSP_SETFMTS)
117 
118  tmp = (s->channels == 2);
119  err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
120  CHECK_IOCTL_ERROR(SNDCTL_DSP_STEREO)
121 
122  tmp = s->sample_rate;
123  err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
124  CHECK_IOCTL_ERROR(SNDCTL_DSP_SPEED)
125  s->sample_rate = tmp; /* store real sample rate */
126  s->fd = audio_fd;
127 
128  return 0;
129  fail:
130  close(audio_fd);
131  return AVERROR(EIO);
132 #undef CHECK_IOCTL_ERROR
133 }
134 
136 {
137  close(s->fd);
138  return 0;
139 }
const char * s
Definition: avisynth_c.h:768
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
#define CHECK_IOCTL_ERROR(event)
Format I/O context.
Definition: avformat.h:1342
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
int channels
Definition: oss.h:32
#define OSS_AUDIO_BLOCK_SIZE
Definition: oss.h:26
enum AVCodecID codec_id
Definition: oss.h:34
#define av_log(a,...)
int ff_oss_audio_open(AVFormatContext *s1, int is_output, const char *audio_device)
Definition: oss.c:40
Main libavdevice API header.
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
static void flip(AVCodecContext *avctx, AVFrame *frame)
Definition: rawdec.c:136
#define AVERROR(e)
Definition: error.h:43
#define fail()
Definition: checkasm.h:116
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
Libavcodec external API header.
int fd
Definition: oss.h:30
int frame_size
Definition: oss.h:33
#define s1
Definition: regdef.h:38
unsigned int flip_left
Definition: oss.h:35
int ff_oss_audio_close(OSSAudioData *s)
Definition: oss.c:135
void * priv_data
Format private data.
Definition: avformat.h:1370
int sample_rate
Definition: oss.h:31
static uint8_t tmp[11]
Definition: aes_ctr.c:26