libavformat/g729dec.c
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00001 /*
00002  * G.729 raw format demuxer
00003  * Copyright (c) 2011 Vladimir Voroshilov
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 "avformat.h"
00023 #include "internal.h"
00024 #include "libavutil/log.h"
00025 #include "libavutil/opt.h"
00026 
00027 typedef struct G729DemuxerContext {
00028     AVClass *class;
00029     int bit_rate;
00030 } G729DemuxerContext;
00031 
00032 static int g729_read_header(AVFormatContext *s, AVFormatParameters *ap)
00033 {
00034     AVStream* st;
00035     G729DemuxerContext *s1 = s->priv_data;
00036 
00037     st = avformat_new_stream(s, NULL);
00038     if (!st)
00039         return AVERROR(ENOMEM);
00040 
00041     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00042     st->codec->codec_id = CODEC_ID_G729;
00043     st->codec->sample_rate = 8000;
00044     st->codec->channels = 1;
00045 
00046     if (s1 && s1->bit_rate) {
00047         s->bit_rate = s1->bit_rate;
00048     }
00049 
00050     if (s->bit_rate == 0) {
00051         av_log(s, AV_LOG_DEBUG, "No bitrate specified. Assuming 8000 b/s\n");
00052         s->bit_rate = 8000;
00053     }
00054 
00055     if (s->bit_rate == 6400) {
00056         st->codec->block_align = 8;
00057     } else if (s->bit_rate == 8000) {
00058         st->codec->block_align = 10;
00059     } else {
00060         av_log(s, AV_LOG_ERROR, "Only 8000 b/s and 6400 b/s bitrates are supported. Provided: %d b/s\n", s->bit_rate);
00061         return AVERROR_INVALIDDATA;
00062     }
00063 
00064     avpriv_set_pts_info(st, st->codec->block_align << 3, 1, st->codec->sample_rate);
00065     return 0;
00066 }
00067 static int g729_read_packet(AVFormatContext *s, AVPacket *pkt)
00068 {
00069     int ret;
00070 
00071     ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);
00072 
00073     pkt->stream_index = 0;
00074     if (ret < 0)
00075         return ret;
00076 
00077     pkt->dts = pkt->pts = pkt->pos / s->streams[0]->codec->block_align;
00078 
00079     return ret;
00080 }
00081 
00082 static const AVOption g729_options[] = {
00083     { "bit_rate", "", offsetof(G729DemuxerContext, bit_rate), AV_OPT_TYPE_INT, {.dbl = 0}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00084     { NULL },
00085 };
00086 
00087 static const AVClass g729_demuxer_class = {
00088     .class_name = "g729 demuxer",
00089     .item_name  = av_default_item_name,
00090     .option     = g729_options,
00091     .version    = LIBAVUTIL_VERSION_INT,
00092 };
00093 
00094 AVInputFormat ff_g729_demuxer = {
00095     .name           = "g729",
00096     .long_name      = NULL_IF_CONFIG_SMALL("G.729 raw format demuxer"),
00097     .priv_data_size = sizeof(G729DemuxerContext),
00098     .read_header    = g729_read_header,
00099     .read_packet    = g729_read_packet,
00100     .flags          = AVFMT_GENERIC_INDEX,
00101     .extensions     = "g729",
00102     .priv_class     = &g729_demuxer_class,
00103 };