FFmpeg
oss.c
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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 "avdevice.h"
36 
37 #include "oss.h"
38 
39 int ff_oss_audio_open(AVFormatContext *s1, int is_output,
40  const char *audio_device)
41 {
42  OSSAudioData *s = s1->priv_data;
43  int audio_fd;
44  int tmp, err;
45  char *flip = getenv("AUDIO_FLIP_LEFT");
46 
47  if (is_output)
48  audio_fd = avpriv_open(audio_device, O_WRONLY);
49  else
50  audio_fd = avpriv_open(audio_device, O_RDONLY);
51  if (audio_fd < 0) {
52  av_log(s1, AV_LOG_ERROR, "%s: %s\n", audio_device, av_err2str(AVERROR(errno)));
53  return AVERROR(EIO);
54  }
55 
56  if (flip && *flip == '1') {
57  s->flip_left = 1;
58  }
59 
60  /* non blocking mode */
61  if (!is_output) {
62  if (fcntl(audio_fd, F_SETFL, O_NONBLOCK) < 0) {
63  av_log(s1, AV_LOG_WARNING, "%s: Could not enable non block mode (%s)\n", audio_device, av_err2str(AVERROR(errno)));
64  }
65  }
66 
67  s->frame_size = OSS_AUDIO_BLOCK_SIZE;
68 
69 #define CHECK_IOCTL_ERROR(event) \
70  if (err < 0) { \
71  av_log(s1, AV_LOG_ERROR, #event ": %s\n", av_err2str(AVERROR(errno)));\
72  goto fail; \
73  }
74 
75  /* select format : favour native format
76  * We don't CHECK_IOCTL_ERROR here because even if failed OSS still may be
77  * usable. If OSS is not usable the SNDCTL_DSP_SETFMTS later is going to
78  * fail anyway. */
79  err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
80  if (err < 0) {
81  av_log(s1, AV_LOG_WARNING, "SNDCTL_DSP_GETFMTS: %s\n", av_err2str(AVERROR(errno)));
82  }
83 
84 #if HAVE_BIGENDIAN
85  if (tmp & AFMT_S16_BE) {
86  tmp = AFMT_S16_BE;
87  } else if (tmp & AFMT_S16_LE) {
88  tmp = AFMT_S16_LE;
89  } else {
90  tmp = 0;
91  }
92 #else
93  if (tmp & AFMT_S16_LE) {
94  tmp = AFMT_S16_LE;
95  } else if (tmp & AFMT_S16_BE) {
96  tmp = AFMT_S16_BE;
97  } else {
98  tmp = 0;
99  }
100 #endif
101 
102  switch(tmp) {
103  case AFMT_S16_LE:
104  s->codec_id = AV_CODEC_ID_PCM_S16LE;
105  s->sample_size = 2;
106  break;
107  case AFMT_S16_BE:
108  s->codec_id = AV_CODEC_ID_PCM_S16BE;
109  s->sample_size = 2;
110  break;
111  default:
112  av_log(s1, AV_LOG_ERROR, "Soundcard does not support 16 bit sample format\n");
113  close(audio_fd);
114  return AVERROR(EIO);
115  }
116  err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
117  CHECK_IOCTL_ERROR(SNDCTL_DSP_SETFMT)
118 
119  tmp = (s->channels == 2);
120  err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
121  CHECK_IOCTL_ERROR(SNDCTL_DSP_STEREO)
122 
123  tmp = s->sample_rate;
124  err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
125  CHECK_IOCTL_ERROR(SNDCTL_DSP_SPEED)
126  s->sample_rate = tmp; /* store real sample rate */
127  s->fd = audio_fd;
128 
129  return 0;
130  fail:
131  close(audio_fd);
132  return AVERROR(EIO);
133 #undef CHECK_IOCTL_ERROR
134 }
135 
137 {
138  close(s->fd);
139  return 0;
140 }
AV_CODEC_ID_PCM_S16LE
@ AV_CODEC_ID_PCM_S16LE
Definition: codec_id.h:320
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
ff_oss_audio_open
int ff_oss_audio_open(AVFormatContext *s1, int is_output, const char *audio_device)
Definition: oss.c:39
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
tmp
static uint8_t tmp[11]
Definition: aes_ctr.c:28
ff_oss_audio_close
int ff_oss_audio_close(OSSAudioData *s)
Definition: oss.c:136
AV_CODEC_ID_PCM_S16BE
@ AV_CODEC_ID_PCM_S16BE
Definition: codec_id.h:321
fail
#define fail()
Definition: checkasm.h:131
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
s
#define s(width, name)
Definition: cbs_vp9.c:256
avpriv_open
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
s1
#define s1
Definition: regdef.h:38
AVFormatContext
Format I/O context.
Definition: avformat.h:1213
OSS_AUDIO_BLOCK_SIZE
#define OSS_AUDIO_BLOCK_SIZE
Definition: oss.h:27
OSSAudioData
Definition: oss.h:29
flip
static void flip(AVCodecContext *avctx, AVFrame *frame)
Definition: rawdec.c:132
av_err2str
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:121
avdevice.h
log.h
CHECK_IOCTL_ERROR
#define CHECK_IOCTL_ERROR(event)
oss.h
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27