/libavformat/g729dec.c

  1/*
  2 * G.729 raw format demuxer
  3 * Copyright (c) 2011 Vladimir Voroshilov
  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 "libavutil/log.h"
 23#include "libavutil/opt.h"
 24
 25#include "avformat.h"
 26#include "internal.h"
 27
 28typedef struct G729DemuxerContext {
 29    AVClass *class;
 30
 31    int bit_rate;
 32} G729DemuxerContext;
 33
 34static int g729_read_header(AVFormatContext *s)
 35{
 36    AVStream* st;
 37    G729DemuxerContext *s1 = s->priv_data;
 38
 39    st = avformat_new_stream(s, NULL);
 40    if (!st)
 41        return AVERROR(ENOMEM);
 42
 43    st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
 44    st->codecpar->codec_id    = AV_CODEC_ID_G729;
 45    st->codecpar->sample_rate = 8000;
 46    st->codecpar->channels    = 1;
 47
 48    if (s1 && s1->bit_rate)
 49        s->bit_rate = s1->bit_rate;
 50
 51    switch(s->bit_rate) {
 52    case 6400:
 53        st->codecpar->block_align = 8;
 54        break;
 55    case 8000:
 56        st->codecpar->block_align = 10;
 57        break;
 58    default:
 59        av_log(s, AV_LOG_ERROR, "Invalid bit_rate value %"PRId64". "
 60               "Only 6400 and 8000 b/s are supported.", s->bit_rate);
 61        return AVERROR(EINVAL);
 62    }
 63
 64    avpriv_set_pts_info(st, 64, 80, st->codecpar->sample_rate);
 65
 66    return 0;
 67}
 68
 69static int g729_read_packet(AVFormatContext *s, AVPacket *pkt)
 70{
 71    AVStream *st = s->streams[0];
 72    int ret = av_get_packet(s->pb, pkt, st->codecpar->block_align);
 73    if (ret < 0)
 74        return ret;
 75
 76    pkt->stream_index = 0;
 77    pkt->dts = pkt->pts = pkt->pos / st->codecpar->block_align;
 78    pkt->duration = 1;
 79
 80    return 0;
 81}
 82
 83#define OFFSET(x) offsetof(G729DemuxerContext, x)
 84static const AVOption g729_options[] = {
 85    { "bit_rate", "", OFFSET(bit_rate), AV_OPT_TYPE_INT, { .i64 = 8000 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
 86    { NULL },
 87};
 88
 89static const AVClass g729_demuxer_class = {
 90    .class_name = "g729 demuxer",
 91    .item_name  = av_default_item_name,
 92    .option     = g729_options,
 93    .version    = LIBAVUTIL_VERSION_INT,
 94};
 95
 96AVInputFormat ff_g729_demuxer = {
 97    .name           = "g729",
 98    .long_name      = NULL_IF_CONFIG_SMALL("G.729 raw format demuxer"),
 99    .priv_data_size = sizeof(G729DemuxerContext),
100    .read_header    = g729_read_header,
101    .read_packet    = g729_read_packet,
102    .flags          = AVFMT_GENERIC_INDEX,
103    .extensions     = "g729",
104    .priv_class     = &g729_demuxer_class,
105};