xref: /third_party/ffmpeg/libavformat/mlpdec.c (revision cabdff1a)
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 "internal.h"
29#include "rawdec.h"
30#include "libavutil/intreadwrite.h"
31#include "libavcodec/mlp.h"
32#include "libavcodec/mlp_parse.h"
33
34static int av_always_inline mlp_thd_probe(const AVProbeData *p, uint32_t sync)
35{
36    const uint8_t *buf, *last_buf = p->buf, *end = p->buf + p->buf_size;
37    int valid = 0, size = 0;
38    int nsubframes = 0;
39
40    for (buf = p->buf; buf + 8 <= end; buf++) {
41        if (AV_RB32(buf + 4) == sync) {
42            if (last_buf + size == buf) {
43                valid += 1 + nsubframes / 8;
44            }
45            nsubframes = 0;
46            last_buf = buf;
47            size = (AV_RB16(buf) & 0xfff) * 2;
48        } else if (buf - last_buf == size) {
49            nsubframes++;
50            size += (AV_RB16(buf) & 0xfff) * 2;
51        }
52    }
53    if (valid >= 100)
54        return AVPROBE_SCORE_MAX;
55    return 0;
56}
57
58static int mlp_read_header(AVFormatContext *s)
59{
60    int ret = ff_raw_audio_read_header(s);
61
62    if (ret < 0)
63        return ret;
64
65    ret = ffio_ensure_seekback(s->pb, 10);
66    if (ret == 0) {
67        uint8_t buffer[10];
68        int read, sample_rate = 0;
69
70        read = avio_read(s->pb, buffer, 10);
71        if (read == 10) {
72            switch (buffer[7]) {
73            case SYNC_TRUEHD:
74                sample_rate = mlp_samplerate(buffer[8] >> 4);
75                break;
76            case SYNC_MLP:
77                sample_rate = mlp_samplerate(buffer[9] >> 4);
78                break;
79            }
80
81            if (sample_rate)
82                avpriv_set_pts_info(s->streams[0], 64, 1, sample_rate);
83        }
84
85        if (read > 0)
86            avio_seek(s->pb, -read, SEEK_CUR);
87    }
88
89    return 0;
90}
91
92#if CONFIG_MLP_DEMUXER
93static int mlp_probe(const AVProbeData *p)
94{
95    return mlp_thd_probe(p, 0xf8726fbb);
96}
97
98const AVInputFormat ff_mlp_demuxer = {
99    .name           = "mlp",
100    .long_name      = NULL_IF_CONFIG_SMALL("raw MLP"),
101    .read_probe     = mlp_probe,
102    .read_header    = mlp_read_header,
103    .read_packet    = ff_raw_read_partial_packet,
104    .flags          = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,
105    .extensions     = "mlp",
106    .raw_codec_id   = AV_CODEC_ID_MLP,
107    .priv_data_size = sizeof(FFRawDemuxerContext),
108    .priv_class     = &ff_raw_demuxer_class,
109};
110#endif
111
112#if CONFIG_TRUEHD_DEMUXER
113static int thd_probe(const AVProbeData *p)
114{
115    return mlp_thd_probe(p, 0xf8726fba);
116}
117
118const AVInputFormat ff_truehd_demuxer = {
119    .name           = "truehd",
120    .long_name      = NULL_IF_CONFIG_SMALL("raw TrueHD"),
121    .read_probe     = thd_probe,
122    .read_header    = mlp_read_header,
123    .read_packet    = ff_raw_read_partial_packet,
124    .flags          = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,
125    .extensions     = "thd",
126    .raw_codec_id   = AV_CODEC_ID_TRUEHD,
127    .priv_data_size = sizeof(FFRawDemuxerContext),
128    .priv_class     = &ff_raw_demuxer_class,
129};
130#endif
131