libavformat/aixdec.c

   1 /*
   2  * AIX demuxer
   3  * Copyright (c) 2016 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 "internal.h"
  25
  26 static int aix_probe(AVProbeData *p)
  27 {
  28     if (AV_RL32(p->buf) != MKTAG('A','I','X','F') ||
  29         AV_RB32(p->buf +  8) != 0x01000014 ||
  30         AV_RB32(p->buf + 12) != 0x00000800)
  31         return 0;
  32
  33     return AVPROBE_SCORE_MAX;
  34 }
  35
  36 static int aix_read_header(AVFormatContext *s)
  37 {
  38     unsigned nb_streams, first_offset, nb_segments;
  39     unsigned stream_list_offset;
  40     unsigned segment_list_offset = 0x20;
  41     unsigned segment_list_entry_size = 0x10;
  42     unsigned size;
  43     int i;
  44
  45     avio_skip(s->pb, 4);
  46     first_offset = avio_rb32(s->pb) + 8;
  47     avio_skip(s->pb, 16);
  48     nb_segments = avio_rb16(s->pb);
  49     if (nb_segments == 0)
  50         return AVERROR_INVALIDDATA;
  51     stream_list_offset = segment_list_offset + segment_list_entry_size * nb_segments + 0x10;
  52     if (stream_list_offset >= first_offset)
  53         return AVERROR_INVALIDDATA;
  54     avio_seek(s->pb, stream_list_offset, SEEK_SET);
  55     nb_streams = avio_r8(s->pb);
  56     if (nb_streams == 0)
  57         return AVERROR_INVALIDDATA;
  58     avio_skip(s->pb, 7);
  59     for (i = 0; i < nb_streams; i++) {
  60         AVStream *st = avformat_new_stream(s, NULL);
  61
  62         if (!st)
  63             return AVERROR(ENOMEM);
  64         st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
  65         st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_ADX;
  66         st->codecpar->sample_rate = avio_rb32(s->pb);
  67         st->codecpar->channels    = avio_r8(s->pb);
  68         avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
  69         avio_skip(s->pb, 3);
  70     }
  71
  72     avio_seek(s->pb, first_offset, SEEK_SET);
  73     for (i = 0; i < nb_streams; i++) {
  74         if (avio_rl32(s->pb) != MKTAG('A','I','X','P'))
  75             return AVERROR_INVALIDDATA;
  76         size = avio_rb32(s->pb);
  77         if (size <= 8)
  78             return AVERROR_INVALIDDATA;
  79         avio_skip(s->pb, 8);
  80         ff_get_extradata(s, s->streams[i]->codecpar, s->pb, size - 8);
  81     }
  82
  83     return 0;
  84 }
  85
  86 static int aix_read_packet(AVFormatContext *s, AVPacket *pkt)
  87 {
  88     unsigned size, index, duration, chunk;
  89     int64_t pos;
  90     int sequence, ret, i;
  91
  92     pos = avio_tell(s->pb);
  93     if (avio_feof(s->pb))
  94         return AVERROR_EOF;
  95     chunk = avio_rl32(s->pb);
  96     size = avio_rb32(s->pb);
  97     if (chunk == MKTAG('A','I','X','E')) {
  98         avio_skip(s->pb, size);
  99         for (i = 0; i < s->nb_streams; i++) {
 100             if (avio_feof(s->pb))
 101                 return AVERROR_EOF;
 102             chunk = avio_rl32(s->pb);
 103             size = avio_rb32(s->pb);
 104             avio_skip(s->pb, size);
 105         }
 106         pos = avio_tell(s->pb);
 107         chunk = avio_rl32(s->pb);
 108         size = avio_rb32(s->pb);
 109     }
 110
 111     if (chunk != MKTAG('A','I','X','P'))
 112         return AVERROR_INVALIDDATA;
 113     if (size <= 8)
 114         return AVERROR_INVALIDDATA;
 115     index = avio_r8(s->pb);
 116     if (avio_r8(s->pb) != s->nb_streams || index >= s->nb_streams)
 117         return AVERROR_INVALIDDATA;
 118     duration = avio_rb16(s->pb);
 119     sequence = avio_rb32(s->pb);
 120     if (sequence < 0) {
 121         avio_skip(s->pb, size - 8);
 122         return 0;
 123     }
 124
 125     ret = av_get_packet(s->pb, pkt, size - 8);
 126     pkt->stream_index = index;
 127     pkt->duration = duration;
 128     pkt->pos = pos;
 129     return ret;
 130 }
 131
 132 AVInputFormat ff_aix_demuxer = {
 133     .name        = "aix",
 134     .long_name   = NULL_IF_CONFIG_SMALL("CRI AIX"),
 135     .read_probe  = aix_probe,
 136     .read_header = aix_read_header,
 137     .read_packet = aix_read_packet,
 138     .extensions  = "aix",
 139     .flags       = AVFMT_GENERIC_INDEX,
 140 };