libavformat/adxdec.c

   1 /*
   2  * Copyright (c) 2011 Justin Ruggles
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * CRI ADX demuxer
  24  */
  25
  26 #include "libavutil/intreadwrite.h"
  27 #include "avformat.h"
  28 #include "demux.h"
  29 #include "internal.h"
  30
  31 #define BLOCK_SIZE    18
  32 #define BLOCK_SAMPLES 32
  33
  34 typedef struct ADXDemuxerContext {
  35     int header_size;
  36 } ADXDemuxerContext;
  37
  38 static int adx_probe(const AVProbeData *p)
  39 {
  40     int offset;
  41     if (AV_RB16(p->buf) != 0x8000)
  42         return 0;
  43     offset = AV_RB16(&p->buf[2]);
  44     if (   offset < 8
  45         || offset > p->buf_size - 4
  46         || memcmp(p->buf + offset - 2, "(c)CRI", 6))
  47         return 0;
  48     return AVPROBE_SCORE_MAX * 3 / 4;
  49 }
  50
  51 static int adx_read_packet(AVFormatContext *s, AVPacket *pkt)
  52 {
  53     ADXDemuxerContext *c = s->priv_data;
  54     AVCodecParameters *par = s->streams[0]->codecpar;
  55     int ret, size;
  56
  57     if (avio_feof(s->pb))
  58         return AVERROR_EOF;
  59
  60     size = BLOCK_SIZE * par->ch_layout.nb_channels;
  61
  62     pkt->pos = avio_tell(s->pb);
  63     pkt->stream_index = 0;
  64
  65     ret = av_get_packet(s->pb, pkt, size * 128);
  66     if (ret < 0)
  67         return ret;
  68     if ((ret % size) && ret >= size) {
  69         size = ret - (ret % size);
  70         av_shrink_packet(pkt, size);
  71         pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
  72     } else if (ret < size) {
  73         return AVERROR(EIO);
  74     } else {
  75         size = ret;
  76     }
  77
  78     pkt->duration = size / (BLOCK_SIZE * par->ch_layout.nb_channels);
  79     pkt->pts      = (pkt->pos - c->header_size) / (BLOCK_SIZE * par->ch_layout.nb_channels);
  80
  81     return 0;
  82 }
  83
  84 static int adx_read_header(AVFormatContext *s)
  85 {
  86     ADXDemuxerContext *c = s->priv_data;
  87     AVCodecParameters *par;
  88     int ret;
  89     int channels;
  90
  91     AVStream *st = avformat_new_stream(s, NULL);
  92     if (!st)
  93         return AVERROR(ENOMEM);
  94     par = s->streams[0]->codecpar;
  95
  96     if (avio_rb16(s->pb) != 0x8000)
  97         return AVERROR_INVALIDDATA;
  98     c->header_size = avio_rb16(s->pb) + 4;
  99     avio_seek(s->pb, -4, SEEK_CUR);
 100
 101     if ((ret = ff_get_extradata(s, par, s->pb, c->header_size)) < 0)
 102         return ret;
 103
 104     if (par->extradata_size < 12) {
 105         av_log(s, AV_LOG_ERROR, "Invalid extradata size.\n");
 106         return AVERROR_INVALIDDATA;
 107     }
 108     channels = AV_RB8 (par->extradata + 7);
 109     par->sample_rate = AV_RB32(par->extradata + 8);
 110
 111     if (channels <= 0) {
 112         av_log(s, AV_LOG_ERROR, "invalid number of channels %d\n", channels);
 113         return AVERROR_INVALIDDATA;
 114     }
 115
 116     if (par->sample_rate <= 0) {
 117         av_log(s, AV_LOG_ERROR, "Invalid sample rate %d\n", par->sample_rate);
 118         return AVERROR_INVALIDDATA;
 119     }
 120
 121     par->ch_layout.nb_channels = channels;
 122     par->codec_type  = AVMEDIA_TYPE_AUDIO;
 123     par->codec_id    = AV_CODEC_ID_ADPCM_ADX;
 124     par->bit_rate    = (int64_t)par->sample_rate * par->ch_layout.nb_channels * BLOCK_SIZE * 8LL / BLOCK_SAMPLES;
 125
 126     avpriv_set_pts_info(st, 64, BLOCK_SAMPLES, par->sample_rate);
 127
 128     return 0;
 129 }
 130
 131 const FFInputFormat ff_adx_demuxer = {
 132     .p.name         = "adx",
 133     .p.long_name    = NULL_IF_CONFIG_SMALL("CRI ADX"),
 134     .p.extensions   = "adx",
 135     .p.flags        = AVFMT_GENERIC_INDEX,
 136     .read_probe     = adx_probe,
 137     .priv_data_size = sizeof(ADXDemuxerContext),
 138     .read_header    = adx_read_header,
 139     .read_packet    = adx_read_packet,
 140     .raw_codec_id   = AV_CODEC_ID_ADPCM_ADX,
 141 };