1 /*
2 * Shorten 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 "avformat.h"
25 #include "rawdec.h"
26 #include "libavcodec/golomb.h"
27
shn_probe(const AVProbeData * p)28 static int shn_probe(const AVProbeData *p)
29 {
30 GetBitContext gb;
31 int version, internal_ftype, channels, blocksize;
32
33 if (AV_RB32(p->buf) != 0x616a6b67)
34 return 0;
35 version = p->buf[4];
36 if (init_get_bits8(&gb, p->buf + 5, p->buf_size - 5 - AV_INPUT_BUFFER_PADDING_SIZE) < 0)
37 return 0;
38 if (!version) {
39 internal_ftype = get_ur_golomb_shorten(&gb, 4);
40 channels = get_ur_golomb_shorten(&gb, 0);
41 blocksize = 256;
42 } else {
43 unsigned k;
44 k = get_ur_golomb_shorten(&gb, 2);
45 if (k > 31)
46 return 0;
47 internal_ftype = get_ur_golomb_shorten(&gb, k);
48 k = get_ur_golomb_shorten(&gb, 2);
49 if (k > 31)
50 return 0;
51 channels = get_ur_golomb_shorten(&gb, k);
52 k = get_ur_golomb_shorten(&gb, 2);
53 if (k > 31)
54 return 0;
55 blocksize = get_ur_golomb_shorten(&gb, k);
56 }
57
58 if (internal_ftype != 2 && internal_ftype != 3 && internal_ftype != 5)
59 return 0;
60 if (channels < 1 || channels > 8)
61 return 0;
62 if (blocksize < 1 || blocksize > 65535)
63 return 0;
64
65 return AVPROBE_SCORE_EXTENSION + 1;
66 }
67
68 const AVInputFormat ff_shorten_demuxer = {
69 .name = "shn",
70 .long_name = NULL_IF_CONFIG_SMALL("raw Shorten"),
71 .read_probe = shn_probe,
72 .read_header = ff_raw_audio_read_header,
73 .read_packet = ff_raw_read_partial_packet,
74 .flags = AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS,
75 .extensions = "shn",
76 .raw_codec_id = AV_CODEC_ID_SHORTEN,
77 .priv_data_size = sizeof(FFRawDemuxerContext),
78 .priv_class = &ff_raw_demuxer_class,
79 };
80