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