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 
ff_oss_audio_open(AVFormatContext * s1,int is_output,const char * audio_device)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 
68     s->frame_size = OSS_AUDIO_BLOCK_SIZE;
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:
105         s->codec_id = AV_CODEC_ID_PCM_S16LE;
106         break;
107     case AFMT_S16_BE:
108         s->codec_id = AV_CODEC_ID_PCM_S16BE;
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 
ff_oss_audio_close(OSSAudioData * s)135 int ff_oss_audio_close(OSSAudioData *s)
136 {
137     close(s->fd);
138     return 0;
139 }
140