2 * Linux audio play interface
3 * Copyright (c) 2000, 2001 Fabrice Bellard
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include <soundcard.h>
29 #include <sys/soundcard.h>
34 #include <sys/ioctl.h>
36 #include "libavutil/internal.h"
37 #include "libavutil/opt.h"
38 #include "libavutil/time.h"
40 #include "libavcodec/avcodec.h"
42 #include "libavformat/avformat.h"
43 #include "libavformat/internal.h"
47 static int audio_read_header(AVFormatContext *s1)
49 OSSAudioData *s = s1->priv_data;
53 st = avformat_new_stream(s1, NULL);
55 return AVERROR(ENOMEM);
58 ret = ff_oss_audio_open(s1, 0, s1->filename);
63 /* take real parameters */
64 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
65 st->codecpar->codec_id = s->codec_id;
66 st->codecpar->sample_rate = s->sample_rate;
67 st->codecpar->channels = s->channels;
69 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
73 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
75 OSSAudioData *s = s1->priv_data;
78 struct audio_buf_info abufi;
80 if ((ret=av_new_packet(pkt, s->frame_size)) < 0)
83 ret = read(s->fd, pkt->data, pkt->size);
87 if (ret<0) return AVERROR(errno);
88 else return AVERROR_EOF;
92 /* compute pts of the start of the packet */
93 cur_time = av_gettime();
95 if (ioctl(s->fd, SNDCTL_DSP_GETISPACE, &abufi) == 0) {
96 bdelay += abufi.bytes;
98 /* subtract time represented by the number of bytes in the audio fifo */
99 cur_time -= (bdelay * 1000000LL) / (s->sample_rate * s->channels);
101 /* convert to wanted units */
104 if (s->flip_left && s->channels == 2) {
106 short *p = (short *) pkt->data;
108 for (i = 0; i < ret; i += 4) {
116 static int audio_read_close(AVFormatContext *s1)
118 OSSAudioData *s = s1->priv_data;
120 ff_oss_audio_close(s);
124 static const AVOption options[] = {
125 { "sample_rate", "", offsetof(OSSAudioData, sample_rate), AV_OPT_TYPE_INT, {.i64 = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
126 { "channels", "", offsetof(OSSAudioData, channels), AV_OPT_TYPE_INT, {.i64 = 2}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
130 static const AVClass oss_demuxer_class = {
131 .class_name = "OSS demuxer",
132 .item_name = av_default_item_name,
134 .version = LIBAVUTIL_VERSION_INT,
137 AVInputFormat ff_oss_demuxer = {
139 .long_name = NULL_IF_CONFIG_SMALL("OSS (Open Sound System) capture"),
140 .priv_data_size = sizeof(OSSAudioData),
141 .read_header = audio_read_header,
142 .read_packet = audio_read_packet,
143 .read_close = audio_read_close,
144 .flags = AVFMT_NOFILE,
145 .priv_class = &oss_demuxer_class,