libavformat/aea.c

   1 /*
   2  * MD STUDIO audio demuxer
   3  *
   4  * Copyright (c) 2009 Benjamin Larsson
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file libavformat/aea.c
  25  */
  26
  27 #include "avformat.h"
  28 #include "raw.h"
  29 #include "libavutil/intreadwrite.h"
  30
  31 #define AT1_SU_SIZE     212
  32
  33 static int aea_read_probe(AVProbeData *p)
  34 {
  35     if (p->buf_size <= 2048+212)
  36         return 0;
  37
  38     /* Magic is '00 08 00 00' in Little Endian*/
  39     if (AV_RL32(p->buf)==0x800) {
  40         int bsm_s, bsm_e, inb_s, inb_e, ch;
  41         ch    = p->buf[264];
  42         bsm_s = p->buf[2048];
  43         inb_s = p->buf[2048+1];
  44         inb_e = p->buf[2048+210];
  45         bsm_e = p->buf[2048+211];
  46
  47         if (ch != 1 && ch != 2)
  48             return 0;
  49
  50         /* Check so that the redundant bsm bytes and info bytes are valid
  51          * the block size mode bytes have to be the same
  52          * the info bytes have to be the same
  53          * the block size mode and info byte can't be the same
  54          */
  55         if (bsm_s == bsm_e && inb_s == inb_e && bsm_s != inb_s)
  56             return AVPROBE_SCORE_MAX / 2;
  57     }
  58     return 0;
  59 }
  60
  61 static int aea_read_header(AVFormatContext *s,
  62                            AVFormatParameters *ap)
  63 {
  64     AVStream *st = av_new_stream(s, 0);
  65     if (!st)
  66         return AVERROR(ENOMEM);
  67
  68     /* Parse the amount of channels and skip to pos 2048(0x800) */
  69     url_fskip(s->pb, 264);
  70     st->codec->channels = get_byte(s->pb);
  71     url_fskip(s->pb, 1783);
  72
  73
  74     st->codec->codec_type     = CODEC_TYPE_AUDIO;
  75     st->codec->codec_id       = CODEC_ID_ATRAC1;
  76     st->codec->sample_rate    = 44100;
  77     st->codec->bit_rate       = 292000;
  78
  79     if (st->codec->channels != 1 && st->codec->channels != 2) {
  80         av_log(s,AV_LOG_ERROR,"Channels %d not supported!\n",st->codec->channels);
  81         return -1;
  82     }
  83
  84     st->codec->channel_layout = (st->codec->channels == 1) ? CH_LAYOUT_MONO : CH_LAYOUT_STEREO;
  85
  86     st->codec->block_align = AT1_SU_SIZE * st->codec->channels;
  87     return 0;
  88 }
  89
  90 static int aea_read_packet(AVFormatContext *s, AVPacket *pkt)
  91 {
  92     int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);
  93
  94     pkt->stream_index = 0;
  95     if (ret <= 0)
  96         return AVERROR(EIO);
  97
  98     return ret;
  99 }
 100
 101 AVInputFormat aea_demuxer = {
 102     "aea",
 103     NULL_IF_CONFIG_SMALL("MD STUDIO audio"),
 104     0,
 105     aea_read_probe,
 106     aea_read_header,
 107     aea_read_packet,
 108     0,
 109     pcm_read_seek,
 110     .flags= AVFMT_GENERIC_INDEX,
 111     .extensions = "aea",
 112 };
 113