/*
  * G.729 raw format demuxer
  * Copyright (c) 2011 Vladimir Voroshilov
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "libavutil/log.h"
 #include "libavutil/opt.h"
 

 #include "avformat.h"
 #include "internal.h"
 

 typedef struct G729DemuxerContext {
     AVClass *class;

     int bit_rate;
 } G729DemuxerContext;
 

 static int g729_read_header(AVFormatContext *s)

 {
     AVStream* st;
     G729DemuxerContext *s1 = s->priv_data;
 
     st = avformat_new_stream(s, NULL);
     if (!st)
         return AVERROR(ENOMEM);
 

     st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
     st->codecpar->codec_id    = AV_CODEC_ID_G729;

     st->codecpar->sample_rate = 8000;

     st->codecpar->channels    = 1;

     if (s1 && s1->bit_rate)

         s->bit_rate = s1->bit_rate;
 

     switch(s->bit_rate) {
     case 6400:

         st->codecpar->block_align = 8;

         break;
     case 8000:

         st->codecpar->block_align = 10;

         break;
     default:

         av_log(s, AV_LOG_ERROR, "Invalid bit_rate value %"PRId64". "

                "Only 6400 and 8000 b/s are supported.", s->bit_rate);
         return AVERROR(EINVAL);

     }
 

     avpriv_set_pts_info(st, st->codecpar->block_align << 3, 1,
                         st->codecpar->sample_rate);
 

     return 0;
 }

 static int g729_read_packet(AVFormatContext *s, AVPacket *pkt)
 {

     AVStream *st = s->streams[0];
     int ret = av_get_packet(s->pb, pkt, st->codecpar->block_align);

     if (ret < 0)
         return ret;
 

     pkt->stream_index = 0;
     pkt->dts = pkt->pts = pkt->pos / st->codecpar->block_align;

     return 0;

 }
 

 #define OFFSET(x) offsetof(G729DemuxerContext, x)

 static const AVOption g729_options[] = {

     { "bit_rate", "", OFFSET(bit_rate), AV_OPT_TYPE_INT, { .i64 = 8000 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },

     { NULL },
 };
 
 static const AVClass g729_demuxer_class = {
     .class_name = "g729 demuxer",
     .item_name  = av_default_item_name,
     .option     = g729_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 AVInputFormat ff_g729_demuxer = {
     .name           = "g729",
     .long_name      = NULL_IF_CONFIG_SMALL("G.729 raw format demuxer"),
     .priv_data_size = sizeof(G729DemuxerContext),
     .read_header    = g729_read_header,
     .read_packet    = g729_read_packet,
     .flags          = AVFMT_GENERIC_INDEX,
     .extensions     = "g729",
     .priv_class     = &g729_demuxer_class,
 };