xref: /third_party/ffmpeg/libavdevice/oss.c (revision cabdff1a)
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
39int 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
136int ff_oss_audio_close(OSSAudioData *s)
137{
138    close(s->fd);
139    return 0;
140}
141