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libavdevice/sndio_dec.c

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00001 /*
00002  * sndio play and grab interface
00003  * Copyright (c) 2010 Jacob Meuser
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <stdint.h>
00023 #include <sndio.h>
00024 
00025 #include "libavformat/avformat.h"
00026 #include "libavutil/opt.h"
00027 
00028 #include "sndio_common.h"
00029 
00030 static av_cold int audio_read_header(AVFormatContext *s1,
00031                                      AVFormatParameters *ap)
00032 {
00033     SndioData *s = s1->priv_data;
00034     AVStream *st;
00035     int ret;
00036 
00037 #if FF_API_FORMAT_PARAMETERS
00038     if (ap->sample_rate > 0)
00039         s->sample_rate = ap->sample_rate;
00040     if (ap->channels > 0)
00041         s->channels = ap->channels;
00042 #endif
00043 
00044     st = av_new_stream(s1, 0);
00045     if (!st)
00046         return AVERROR(ENOMEM);
00047 
00048     ret = ff_sndio_open(s1, 0, s1->filename);
00049     if (ret < 0)
00050         return ret;
00051 
00052     /* take real parameters */
00053     st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
00054     st->codec->codec_id    = s->codec_id;
00055     st->codec->sample_rate = s->sample_rate;
00056     st->codec->channels    = s->channels;
00057 
00058     av_set_pts_info(st, 64, 1, 1000000);  /* 64 bits pts in us */
00059 
00060     return 0;
00061 }
00062 
00063 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
00064 {
00065     SndioData *s = s1->priv_data;
00066     int64_t bdelay, cur_time;
00067     int ret;
00068 
00069     if ((ret = av_new_packet(pkt, s->buffer_size)) < 0)
00070         return ret;
00071 
00072     ret = sio_read(s->hdl, pkt->data, pkt->size);
00073     if (ret == 0 || sio_eof(s->hdl)) {
00074         av_free_packet(pkt);
00075         return AVERROR_EOF;
00076     }
00077 
00078     pkt->size   = ret;
00079     s->softpos += ret;
00080 
00081     /* compute pts of the start of the packet */
00082     cur_time = av_gettime();
00083 
00084     bdelay = ret + s->hwpos - s->softpos;
00085 
00086     /* convert to pts */
00087     pkt->pts = cur_time - ((bdelay * 1000000) /
00088         (s->bps * s->channels * s->sample_rate));
00089 
00090     return 0;
00091 }
00092 
00093 static av_cold int audio_read_close(AVFormatContext *s1)
00094 {
00095     SndioData *s = s1->priv_data;
00096 
00097     ff_sndio_close(s);
00098 
00099     return 0;
00100 }
00101 
00102 static const AVOption options[] = {
00103     { "sample_rate", "", offsetof(SndioData, sample_rate), FF_OPT_TYPE_INT, {.dbl = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00104     { "channels",    "", offsetof(SndioData, channels),    FF_OPT_TYPE_INT, {.dbl = 2},     1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00105     { NULL },
00106 };
00107 
00108 static const AVClass sndio_demuxer_class = {
00109     .class_name     = "sndio indev",
00110     .item_name      = av_default_item_name,
00111     .option         = options,
00112     .version        = LIBAVUTIL_VERSION_INT,
00113 };
00114 
00115 AVInputFormat ff_sndio_demuxer = {
00116     .name           = "sndio",
00117     .long_name      = NULL_IF_CONFIG_SMALL("sndio audio capture"),
00118     .priv_data_size = sizeof(SndioData),
00119     .read_header    = audio_read_header,
00120     .read_packet    = audio_read_packet,
00121     .read_close     = audio_read_close,
00122     .flags          = AVFMT_NOFILE,
00123     .priv_class     = &sndio_demuxer_class,
00124 };

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