libavformat/vocdec.c

   1 /*
   2  * Creative Voice File demuxer.
   3  * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 "voc.h"
  24 #include "internal.h"
  25
  26
  27 static int voc_probe(AVProbeData *p)
  28 {
  29     int version, check;
  30
  31     if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
  32         return 0;
  33     version = AV_RL16(p->buf + 22);
  34     check = AV_RL16(p->buf + 24);
  35     if (~version + 0x1234 != check)
  36         return 10;
  37
  38     return AVPROBE_SCORE_MAX;
  39 }
  40
  41 static int voc_read_header(AVFormatContext *s)
  42 {
  43     VocDecContext *voc = s->priv_data;
  44     AVIOContext *pb = s->pb;
  45     int header_size;
  46     AVStream *st;
  47
  48     avio_skip(pb, 20);
  49     header_size = avio_rl16(pb) - 22;
  50     if (header_size != 4) {
  51         av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
  52         return AVERROR(ENOSYS);
  53     }
  54     avio_skip(pb, header_size);
  55     st = avformat_new_stream(s, NULL);
  56     if (!st)
  57         return AVERROR(ENOMEM);
  58     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  59
  60     voc->remaining_size = 0;
  61     return 0;
  62 }
  63
  64 int
  65 ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
  66 {
  67     VocDecContext *voc = s->priv_data;
  68     AVCodecContext *dec = st->codec;
  69     AVIOContext *pb = s->pb;
  70     VocType type;
  71     int size, tmp_codec=-1;
  72     int sample_rate = 0;
  73     int channels = 1;
  74
  75     while (!voc->remaining_size) {
  76         type = avio_r8(pb);
  77         if (type == VOC_TYPE_EOF)
  78             return AVERROR(EIO);
  79         voc->remaining_size = avio_rl24(pb);
  80         if (!voc->remaining_size) {
  81             if (!s->pb->seekable)
  82                 return AVERROR(EIO);
  83             voc->remaining_size = avio_size(pb) - avio_tell(pb);
  84         }
  85         max_size -= 4;
  86
  87         switch (type) {
  88         case VOC_TYPE_VOICE_DATA:
  89             if (!dec->sample_rate) {
  90                 dec->sample_rate = 1000000 / (256 - avio_r8(pb));
  91                 if (sample_rate)
  92                     dec->sample_rate = sample_rate;
  93                 avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
  94             } else
  95                 avio_skip(pb, 1);
  96             dec->channels = channels;
  97             tmp_codec = avio_r8(pb);
  98             dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);
  99             voc->remaining_size -= 2;
 100             max_size -= 2;
 101             channels = 1;
 102             break;
 103
 104         case VOC_TYPE_VOICE_DATA_CONT:
 105             break;
 106
 107         case VOC_TYPE_EXTENDED:
 108             sample_rate = avio_rl16(pb);
 109             avio_r8(pb);
 110             channels = avio_r8(pb) + 1;
 111             sample_rate = 256000000 / (channels * (65536 - sample_rate));
 112             voc->remaining_size = 0;
 113             max_size -= 4;
 114             break;
 115
 116         case VOC_TYPE_NEW_VOICE_DATA:
 117             if (!dec->sample_rate) {
 118                 dec->sample_rate = avio_rl32(pb);
 119                 avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
 120             } else
 121                 avio_skip(pb, 4);
 122             dec->bits_per_coded_sample = avio_r8(pb);
 123             dec->channels = avio_r8(pb);
 124             tmp_codec = avio_rl16(pb);
 125             avio_skip(pb, 4);
 126             voc->remaining_size -= 12;
 127             max_size -= 12;
 128             break;
 129
 130         default:
 131             avio_skip(pb, voc->remaining_size);
 132             max_size -= voc->remaining_size;
 133             voc->remaining_size = 0;
 134             break;
 135         }
 136     }
 137
 138     if (tmp_codec >= 0) {
 139         tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec);
 140         if (dec->codec_id == AV_CODEC_ID_NONE)
 141             dec->codec_id = tmp_codec;
 142         else if (dec->codec_id != tmp_codec)
 143             av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n");
 144         if (dec->codec_id == AV_CODEC_ID_NONE) {
 145             if (s->audio_codec_id == AV_CODEC_ID_NONE) {
 146                 av_log(s, AV_LOG_ERROR, "unknown codec tag\n");
 147                 return AVERROR(EINVAL);
 148             }
 149             av_log(s, AV_LOG_WARNING, "unknown codec tag\n");
 150         }
 151     }
 152
 153     dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample;
 154
 155     if (max_size <= 0)
 156         max_size = 2048;
 157     size = FFMIN(voc->remaining_size, max_size);
 158     voc->remaining_size -= size;
 159     return av_get_packet(pb, pkt, size);
 160 }
 161
 162 static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
 163 {
 164     return ff_voc_get_packet(s, pkt, s->streams[0], 0);
 165 }
 166
 167 AVInputFormat ff_voc_demuxer = {
 168     .name           = "voc",
 169     .long_name      = NULL_IF_CONFIG_SMALL("Creative Voice"),
 170     .priv_data_size = sizeof(VocDecContext),
 171     .read_probe     = voc_probe,
 172     .read_header    = voc_read_header,
 173     .read_packet    = voc_read_packet,
 174     .codec_tag      = (const AVCodecTag* const []){ ff_voc_codec_tags, 0 },
 175 };