ffmpeg/libavdevice/sndio_dec.c

   1 /*
   2  * sndio play and grab interface
   3  * Copyright (c) 2010 Jacob Meuser
   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 <stdint.h>
  23 #include <sndio.h>
  24
  25 #include "libavformat/avformat.h"
  26 #include "libavformat/internal.h"
  27 #include "libavutil/opt.h"
  28 #include "libavutil/time.h"
  29
  30 #include "sndio_common.h"
  31
  32 static av_cold int audio_read_header(AVFormatContext *s1)
  33 {
  34     SndioData *s = s1->priv_data;
  35     AVStream *st;
  36     int ret;
  37
  38     st = avformat_new_stream(s1, NULL);
  39     if (!st)
  40         return AVERROR(ENOMEM);
  41
  42     ret = ff_sndio_open(s1, 0, s1->filename);
  43     if (ret < 0)
  44         return ret;
  45
  46     /* take real parameters */
  47     st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
  48     st->codec->codec_id    = s->codec_id;
  49     st->codec->sample_rate = s->sample_rate;
  50     st->codec->channels    = s->channels;
  51
  52     avpriv_set_pts_info(st, 64, 1, 1000000);  /* 64 bits pts in us */
  53
  54     return 0;
  55 }
  56
  57 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
  58 {
  59     SndioData *s = s1->priv_data;
  60     int64_t bdelay, cur_time;
  61     int ret;
  62
  63     if ((ret = av_new_packet(pkt, s->buffer_size)) < 0)
  64         return ret;
  65
  66     ret = sio_read(s->hdl, pkt->data, pkt->size);
  67     if (ret == 0 || sio_eof(s->hdl)) {
  68         av_free_packet(pkt);
  69         return AVERROR_EOF;
  70     }
  71
  72     pkt->size   = ret;
  73     s->softpos += ret;
  74
  75     /* compute pts of the start of the packet */
  76     cur_time = av_gettime();
  77
  78     bdelay = ret + s->hwpos - s->softpos;
  79
  80     /* convert to pts */
  81     pkt->pts = cur_time - ((bdelay * 1000000) /
  82         (s->bps * s->channels * s->sample_rate));
  83
  84     return 0;
  85 }
  86
  87 static av_cold int audio_read_close(AVFormatContext *s1)
  88 {
  89     SndioData *s = s1->priv_data;
  90
  91     ff_sndio_close(s);
  92
  93     return 0;
  94 }
  95
  96 static const AVOption options[] = {
  97     { "sample_rate", "", offsetof(SndioData, sample_rate), AV_OPT_TYPE_INT, {.i64 = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
  98     { "channels",    "", offsetof(SndioData, channels),    AV_OPT_TYPE_INT, {.i64 = 2},     1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
  99     { NULL },
 100 };
 101
 102 static const AVClass sndio_demuxer_class = {
 103     .class_name     = "sndio indev",
 104     .item_name      = av_default_item_name,
 105     .option         = options,
 106     .version        = LIBAVUTIL_VERSION_INT,
 107     .category       = AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
 108 };
 109
 110 AVInputFormat ff_sndio_demuxer = {
 111     .name           = "sndio",
 112     .long_name      = NULL_IF_CONFIG_SMALL("sndio audio capture"),
 113     .priv_data_size = sizeof(SndioData),
 114     .read_header    = audio_read_header,
 115     .read_packet    = audio_read_packet,
 116     .read_close     = audio_read_close,
 117     .flags          = AVFMT_NOFILE,
 118     .priv_class     = &sndio_demuxer_class,
 119 };