1/*
2 * RAW DTS demuxer
3 * Copyright (c) 2008 Benjamin Larsson
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 "libavcodec/bytestream.h"
23#include "avformat.h"
24#include "rawdec.h"
25
26#define DCA_MARKER_14B_BE 0x1FFFE800
27#define DCA_MARKER_14B_LE 0xFF1F00E8
28#define DCA_MARKER_RAW_BE 0x7FFE8001
29#define DCA_MARKER_RAW_LE 0xFE7F0180
30
31static int dts_probe(AVProbeData *p)
32{
33    const uint8_t *buf, *bufp;
34    uint32_t state = -1;
35    int markers[3] = {0};
36    int sum, max;
37    int64_t diff = 0;
38
39    buf = p->buf;
40
41    for(; buf < (p->buf+p->buf_size)-2; buf+=2) {
42        bufp = buf;
43        state = (state << 16) | bytestream_get_be16(&bufp);
44
45        /* regular bitstream */
46        if (state == DCA_MARKER_RAW_BE || state == DCA_MARKER_RAW_LE)
47            markers[0]++;
48
49        /* 14 bits big-endian bitstream */
50        if (state == DCA_MARKER_14B_BE)
51            if ((bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
52                markers[1]++;
53
54        /* 14 bits little-endian bitstream */
55        if (state == DCA_MARKER_14B_LE)
56            if ((bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
57                markers[2]++;
58
59        if (buf - p->buf >= 4)
60            diff += FFABS(AV_RL16(buf) - AV_RL16(buf-4));
61    }
62    sum = markers[0] + markers[1] + markers[2];
63    max = markers[1] > markers[0];
64    max = markers[2] > markers[max] ? 2 : max;
65    if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
66        markers[max] * 4 > sum * 3 &&
67        diff / p->buf_size > 200)
68        return AVPROBE_SCORE_EXTENSION + 1;
69
70    return 0;
71}
72
73AVInputFormat ff_dts_demuxer = {
74    .name           = "dts",
75    .long_name      = NULL_IF_CONFIG_SMALL("raw DTS"),
76    .read_probe     = dts_probe,
77    .read_header    = ff_raw_audio_read_header,
78    .read_packet    = ff_raw_read_partial_packet,
79    .flags          = AVFMT_GENERIC_INDEX,
80    .extensions     = "dts",
81    .raw_codec_id   = AV_CODEC_ID_DTS,
82};
83