1 /*
2 * Linux audio play 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 <stdint.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/internal.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/time.h"
36
37 #include "avdevice.h"
38 #include "libavformat/internal.h"
39
40 #include "oss.h"
41
audio_read_header(AVFormatContext * s1)42 static int audio_read_header(AVFormatContext *s1)
43 {
44 OSSAudioData *s = s1->priv_data;
45 AVStream *st;
46 int ret;
47
48 st = avformat_new_stream(s1, NULL);
49 if (!st) {
50 return AVERROR(ENOMEM);
51 }
52
53 ret = ff_oss_audio_open(s1, 0, s1->url);
54 if (ret < 0) {
55 return AVERROR(EIO);
56 }
57
58 /* take real parameters */
59 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
60 st->codecpar->codec_id = s->codec_id;
61 st->codecpar->sample_rate = s->sample_rate;
62 st->codecpar->ch_layout.nb_channels = s->channels;
63
64 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
65 return 0;
66 }
67
audio_read_packet(AVFormatContext * s1,AVPacket * pkt)68 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
69 {
70 OSSAudioData *s = s1->priv_data;
71 int ret, bdelay;
72 int64_t cur_time;
73 struct audio_buf_info abufi;
74
75 if ((ret=av_new_packet(pkt, s->frame_size)) < 0)
76 return ret;
77
78 ret = read(s->fd, pkt->data, pkt->size);
79 if (ret <= 0){
80 av_packet_unref(pkt);
81 pkt->size = 0;
82 if (ret<0) return AVERROR(errno);
83 else return AVERROR_EOF;
84 }
85 pkt->size = ret;
86
87 /* compute pts of the start of the packet */
88 cur_time = av_gettime();
89 bdelay = ret;
90 if (ioctl(s->fd, SNDCTL_DSP_GETISPACE, &abufi) == 0) {
91 bdelay += abufi.bytes;
92 }
93 /* subtract time represented by the number of bytes in the audio fifo */
94 cur_time -= (bdelay * 1000000LL) / (s->sample_rate * s->sample_size * s->channels);
95
96 /* convert to wanted units */
97 pkt->pts = cur_time;
98
99 if (s->flip_left && s->channels == 2) {
100 int i;
101 short *p = (short *) pkt->data;
102
103 for (i = 0; i < ret; i += 4) {
104 *p = ~*p;
105 p += 2;
106 }
107 }
108 return 0;
109 }
110
audio_read_close(AVFormatContext * s1)111 static int audio_read_close(AVFormatContext *s1)
112 {
113 OSSAudioData *s = s1->priv_data;
114
115 ff_oss_audio_close(s);
116 return 0;
117 }
118
119 static const AVOption options[] = {
120 { "sample_rate", "", offsetof(OSSAudioData, sample_rate), AV_OPT_TYPE_INT, {.i64 = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
121 { "channels", "", offsetof(OSSAudioData, channels), AV_OPT_TYPE_INT, {.i64 = 2}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
122 { NULL },
123 };
124
125 static const AVClass oss_demuxer_class = {
126 .class_name = "OSS indev",
127 .item_name = av_default_item_name,
128 .option = options,
129 .version = LIBAVUTIL_VERSION_INT,
130 .category = AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
131 };
132
133 const AVInputFormat ff_oss_demuxer = {
134 .name = "oss",
135 .long_name = NULL_IF_CONFIG_SMALL("OSS (Open Sound System) capture"),
136 .priv_data_size = sizeof(OSSAudioData),
137 .read_header = audio_read_header,
138 .read_packet = audio_read_packet,
139 .read_close = audio_read_close,
140 .flags = AVFMT_NOFILE,
141 .priv_class = &oss_demuxer_class,
142 };
143