libavformat/acedec.c

   1 /*
   2  * ACE demuxer
   3  * Copyright (c) 2020 Paul B Mahol
   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/intreadwrite.h"
  23 #include "avformat.h"
  24 #include "demux.h"
  25 #include "internal.h"
  26
  27 static int ace_probe(const AVProbeData *p)
  28 {
  29     uint32_t asc;
  30
  31     if (AV_RB32(p->buf) != MKBETAG('A','A','C',' '))
  32         return 0;
  33     if (p->buf_size < 0x44)
  34         return 0;
  35     asc = AV_RB32(p->buf + 0x40);
  36     if (asc < 0x44 || asc > p->buf_size - 4)
  37         return 0;
  38     if (AV_RB32(p->buf + asc) != MKBETAG('A','S','C',' '))
  39         return 0;
  40
  41     return AVPROBE_SCORE_MAX / 2 + 1;
  42 }
  43
  44 static int ace_read_header(AVFormatContext *s)
  45 {
  46     AVIOContext *pb = s->pb;
  47     AVCodecParameters *par;
  48     int ret, codec, rate, nb_channels;
  49     uint32_t asc_pos, size;
  50     AVStream *st;
  51
  52     avio_skip(pb, 0x40);
  53     asc_pos = avio_rb32(pb);
  54     if (asc_pos < 0x44)
  55         return AVERROR_INVALIDDATA;
  56     avio_skip(pb, asc_pos - 0x44);
  57     if (avio_rb32(pb) != MKBETAG('A','S','C',' '))
  58         return AVERROR_INVALIDDATA;
  59     avio_skip(pb, 0xec);
  60     codec = avio_rb32(pb);
  61     nb_channels = avio_rb32(pb);
  62     if (nb_channels <= 0 || nb_channels > 8)
  63         return AVERROR_INVALIDDATA;
  64     size = avio_rb32(pb);
  65     if (size == 0)
  66         return AVERROR_INVALIDDATA;
  67     rate = avio_rb32(pb);
  68     if (rate <= 0)
  69         return AVERROR_INVALIDDATA;
  70     avio_skip(pb, 16);
  71
  72     st = avformat_new_stream(s, NULL);
  73     if (!st)
  74         return AVERROR(ENOMEM);
  75     st->start_time = 0;
  76     par = st->codecpar;
  77     par->codec_type  = AVMEDIA_TYPE_AUDIO;
  78     par->ch_layout.nb_channels = nb_channels;
  79     par->sample_rate = rate;
  80     par->block_align = (codec == 4 ? 0x60 : codec == 5 ? 0x98 : 0xC0) * nb_channels;
  81     st->duration     = (size / par->block_align) * 1024LL;
  82     par->codec_id    = AV_CODEC_ID_ATRAC3;
  83
  84     ret = ff_alloc_extradata(par, 14);
  85     if (ret < 0)
  86         return ret;
  87
  88     AV_WL16(st->codecpar->extradata, 1);
  89     AV_WL16(st->codecpar->extradata+2, 2048 * nb_channels);
  90     AV_WL16(st->codecpar->extradata+4, 0);
  91     AV_WL16(st->codecpar->extradata+6, codec == 4 ? 1 : 0);
  92     AV_WL16(st->codecpar->extradata+8, codec == 4 ? 1 : 0);
  93     AV_WL16(st->codecpar->extradata+10, 1);
  94     AV_WL16(st->codecpar->extradata+12, 0);
  95
  96     avpriv_set_pts_info(st, 64, 1, par->sample_rate);
  97
  98     return 0;
  99 }
 100
 101 static int ace_read_packet(AVFormatContext *s, AVPacket *pkt)
 102 {
 103     AVCodecParameters *par = s->streams[0]->codecpar;
 104
 105     return av_get_packet(s->pb, pkt, par->block_align);
 106 }
 107
 108 const FFInputFormat ff_ace_demuxer = {
 109     .p.name         = "ace",
 110     .p.long_name    = NULL_IF_CONFIG_SMALL("tri-Ace Audio Container"),
 111     .p.flags        = AVFMT_GENERIC_INDEX,
 112     .read_probe     = ace_probe,
 113     .read_header    = ace_read_header,
 114     .read_packet    = ace_read_packet,
 115 };