libavformat/mlpdec.c

   1 /*
   2  * MLP and TrueHD demuxer
   3  * Copyright (c) 2001 Fabrice Bellard
   4  * Copyright (c) 2005 Alex Beregszaszi
   5  * Copyright (c) 2015 Carl Eugen Hoyos
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include "config_components.h"
  25
  26 #include "avformat.h"
  27 #include "avio_internal.h"
  28 #include "demux.h"
  29 #include "internal.h"
  30 #include "rawdec.h"
  31 #include "libavutil/intreadwrite.h"
  32 #include "libavcodec/mlp.h"
  33 #include "libavcodec/mlp_parse.h"
  34
  35 static int av_always_inline mlp_thd_probe(const AVProbeData *p, uint32_t sync)
  36 {
  37     const uint8_t *buf, *last_buf = p->buf, *end = p->buf + p->buf_size;
  38     int valid = 0, size = 0;
  39     int nsubframes = 0;
  40
  41     for (buf = p->buf; buf + 8 <= end; buf++) {
  42         if (AV_RB32(buf + 4) == sync) {
  43             if (last_buf + size == buf) {
  44                 valid += 1 + nsubframes / 8;
  45             }
  46             nsubframes = 0;
  47             last_buf = buf;
  48             size = (AV_RB16(buf) & 0xfff) * 2;
  49         } else if (buf - last_buf == size) {
  50             nsubframes++;
  51             size += (AV_RB16(buf) & 0xfff) * 2;
  52         }
  53     }
  54     if (valid >= 100)
  55         return AVPROBE_SCORE_MAX;
  56     return 0;
  57 }
  58
  59 static int mlp_read_header(AVFormatContext *s)
  60 {
  61     int ret = ff_raw_audio_read_header(s);
  62
  63     if (ret < 0)
  64         return ret;
  65
  66     ret = ffio_ensure_seekback(s->pb, 10);
  67     if (ret == 0) {
  68         uint8_t buffer[10];
  69         int read, sample_rate = 0;
  70
  71         read = avio_read(s->pb, buffer, 10);
  72         if (read == 10) {
  73             switch (buffer[7]) {
  74             case SYNC_TRUEHD:
  75                 sample_rate = mlp_samplerate(buffer[8] >> 4);
  76                 break;
  77             case SYNC_MLP:
  78                 sample_rate = mlp_samplerate(buffer[9] >> 4);
  79                 break;
  80             }
  81
  82             if (sample_rate)
  83                 avpriv_set_pts_info(s->streams[0], 64, 1, sample_rate);
  84         }
  85
  86         if (read > 0)
  87             avio_seek(s->pb, -read, SEEK_CUR);
  88     }
  89
  90     return 0;
  91 }
  92
  93 #if CONFIG_MLP_DEMUXER
  94 static int mlp_probe(const AVProbeData *p)
  95 {
  96     return mlp_thd_probe(p, 0xf8726fbb);
  97 }
  98
  99 const FFInputFormat ff_mlp_demuxer = {
 100     .p.name         = "mlp",
 101     .p.long_name    = NULL_IF_CONFIG_SMALL("raw MLP"),
 102     .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,
 103     .p.extensions   = "mlp",
 104     .p.priv_class   = &ff_raw_demuxer_class,
 105     .read_probe     = mlp_probe,
 106     .read_header    = mlp_read_header,
 107     .read_packet    = ff_raw_read_partial_packet,
 108     .raw_codec_id   = AV_CODEC_ID_MLP,
 109     .priv_data_size = sizeof(FFRawDemuxerContext),
 110 };
 111 #endif
 112
 113 #if CONFIG_TRUEHD_DEMUXER
 114 static int thd_probe(const AVProbeData *p)
 115 {
 116     return mlp_thd_probe(p, 0xf8726fba);
 117 }
 118
 119 const FFInputFormat ff_truehd_demuxer = {
 120     .p.name         = "truehd",
 121     .p.long_name    = NULL_IF_CONFIG_SMALL("raw TrueHD"),
 122     .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,
 123     .p.extensions   = "thd",
 124     .p.priv_class   = &ff_raw_demuxer_class,
 125     .read_probe     = thd_probe,
 126     .read_header    = mlp_read_header,
 127     .read_packet    = ff_raw_read_partial_packet,
 128     .raw_codec_id   = AV_CODEC_ID_TRUEHD,
 129     .priv_data_size = sizeof(FFRawDemuxerContext),
 130 };
 131 #endif