1 /*
2 * HCOM demuxer
3 * Copyright (c) 2019 Paul B Mahol
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 "libavutil/intreadwrite.h"
23 #include "libavcodec/internal.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "pcm.h"
27
hcom_probe(const AVProbeData * p)28 static int hcom_probe(const AVProbeData *p)
29 {
30 if (p->buf_size < 132)
31 return 0;
32 if (!memcmp(p->buf+65, "FSSD", 4) &&
33 !memcmp(p->buf+128, "HCOM", 4))
34 return AVPROBE_SCORE_MAX;
35 return 0;
36 }
37
hcom_read_header(AVFormatContext * s)38 static int hcom_read_header(AVFormatContext *s)
39 {
40 AVStream *st;
41 av_unused unsigned data_size, rsrc_size, huffcount;
42 unsigned compresstype, divisor;
43 unsigned dict_entries;
44 int ret;
45
46 avio_skip(s->pb, 83);
47 data_size = avio_rb32(s->pb);
48 rsrc_size = avio_rb32(s->pb);
49 avio_skip(s->pb, 128-91+4);
50 huffcount = avio_rb32(s->pb);
51 avio_skip(s->pb, 4);
52 compresstype = avio_rb32(s->pb);
53 if (compresstype > 1)
54 return AVERROR_INVALIDDATA;
55 divisor = avio_rb32(s->pb);
56 if (divisor == 0 || divisor > 4)
57 return AVERROR_INVALIDDATA;
58 dict_entries = avio_rb16(s->pb);
59
60 st = avformat_new_stream(s, NULL);
61 if (!st)
62 return AVERROR(ENOMEM);
63
64 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
65 st->codecpar->channels = 1;
66 st->codecpar->sample_rate = 22050 / divisor;
67 st->codecpar->codec_id = AV_CODEC_ID_HCOM;
68 st->codecpar->bits_per_coded_sample = 8;
69 st->codecpar->block_align = 4;
70
71 ret = ff_alloc_extradata(st->codecpar, dict_entries * 4 + 7);
72 if (ret < 0)
73 return ret;
74 AV_WB16(st->codecpar->extradata, dict_entries);
75 AV_WB32(st->codecpar->extradata + 2, compresstype);
76 avio_read(s->pb, st->codecpar->extradata + 6, dict_entries * 4);
77 avio_skip(s->pb, 1);
78 st->codecpar->extradata[dict_entries * 4 + 6] = avio_r8(s->pb);
79
80 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
81
82 return 0;
83 }
84
85 AVInputFormat ff_hcom_demuxer = {
86 .name = "hcom",
87 .long_name = NULL_IF_CONFIG_SMALL("Macintosh HCOM"),
88 .read_probe = hcom_probe,
89 .read_header = hcom_read_header,
90 .read_packet = ff_pcm_read_packet,
91 };
92