libavformat/dcstr.c

   1 /*
   2  * DC STR demuxer
   3  * Copyright (c) 2015 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 "avformat.h"
  23 #include "demux.h"
  24 #include "internal.h"
  25
  26 static int dcstr_probe(const AVProbeData *p)
  27 {
  28     if (p->buf_size < 224 || memcmp(p->buf + 213, "Sega Stream", 11))
  29         return 0;
  30
  31     return AVPROBE_SCORE_MAX;
  32 }
  33
  34 static int dcstr_read_header(AVFormatContext *s)
  35 {
  36     unsigned codec, align;
  37     int mult;
  38     AVStream *st;
  39
  40     st = avformat_new_stream(s, NULL);
  41     if (!st)
  42         return AVERROR(ENOMEM);
  43
  44     st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
  45     st->codecpar->ch_layout.nb_channels = avio_rl32(s->pb);
  46     st->codecpar->sample_rate = avio_rl32(s->pb);
  47     if (st->codecpar->sample_rate <= 0)
  48         return AVERROR_INVALIDDATA;
  49     codec                  = avio_rl32(s->pb);
  50     align                  = avio_rl32(s->pb);
  51     avio_skip(s->pb, 4);
  52     st->duration           = avio_rl32(s->pb);
  53     mult                   = avio_rl32(s->pb);
  54     if (st->codecpar->ch_layout.nb_channels <= 0 || mult <= 0 ||
  55         mult > INT_MAX / st->codecpar->ch_layout.nb_channels) {
  56         av_log(s, AV_LOG_ERROR, "invalid number of channels %d x %d\n",
  57                st->codecpar->ch_layout.nb_channels, mult);
  58         return AVERROR_INVALIDDATA;
  59     }
  60     st->codecpar->ch_layout.nb_channels *= mult;
  61     if (!align || align > INT_MAX / st->codecpar->ch_layout.nb_channels)
  62         return AVERROR_INVALIDDATA;
  63     st->codecpar->block_align = align * st->codecpar->ch_layout.nb_channels;
  64
  65     switch (codec) {
  66     case  4: st->codecpar->codec_id = AV_CODEC_ID_ADPCM_AICA;       break;
  67     case 16: st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE_PLANAR; break;
  68     default: avpriv_request_sample(s, "codec %X", codec);
  69              return AVERROR_PATCHWELCOME;
  70     }
  71
  72     avio_skip(s->pb, 0x800 - avio_tell(s->pb));
  73     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
  74
  75     return 0;
  76 }
  77
  78 static int dcstr_read_packet(AVFormatContext *s, AVPacket *pkt)
  79 {
  80     AVCodecParameters *par    = s->streams[0]->codecpar;
  81     return av_get_packet(s->pb, pkt, par->block_align);
  82 }
  83
  84 const FFInputFormat ff_dcstr_demuxer = {
  85     .p.name         = "dcstr",
  86     .p.long_name    = NULL_IF_CONFIG_SMALL("Sega DC STR"),
  87     .p.extensions   = "str",
  88     .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NO_BYTE_SEEK | AVFMT_NOBINSEARCH,
  89     .read_probe     = dcstr_probe,
  90     .read_header    = dcstr_read_header,
  91     .read_packet    = dcstr_read_packet,
  92 };