Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
Download
52868 views
Tweet
Share
Share
1
/*

2
 * CRYO APC audio format demuxer

3
 * Copyright (c) 2007 Anssi Hannula <[email protected]>

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 <string.h>

23


24
#include "libavutil/channel_layout.h"

25
#include "avformat.h"

26
#include "internal.h"

27


28
static int apc_probe(AVProbeData *p)

29
{

30
    if (!strncmp(p->buf, "CRYO_APC", 8))

31
        return AVPROBE_SCORE_MAX;

32


33
    return 0;

34
}

35


36
static int apc_read_header(AVFormatContext *s)

37
{

38
    AVIOContext *pb = s->pb;

39
    AVStream *st;

40


41
    avio_rl32(pb); /* CRYO */

42
    avio_rl32(pb); /* _APC */

43
    avio_rl32(pb); /* 1.20 */

44


45
    st = avformat_new_stream(s, NULL);

46
    if (!st)

47
        return AVERROR(ENOMEM);

48


49
    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

50
    st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;

51


52
    avio_rl32(pb); /* number of samples */

53
    st->codec->sample_rate = avio_rl32(pb);

54


55
    /* initial predictor values for adpcm decoder */

56
    if (ff_get_extradata(st->codec, pb, 2 * 4) < 0)

57
        return AVERROR(ENOMEM);

58


59
    if (avio_rl32(pb)) {

60
        st->codec->channels       = 2;

61
        st->codec->channel_layout = AV_CH_LAYOUT_STEREO;

62
    } else {

63
        st->codec->channels       = 1;

64
        st->codec->channel_layout = AV_CH_LAYOUT_MONO;

65
    }

66


67
    st->codec->bits_per_coded_sample = 4;

68
    st->codec->bit_rate = st->codec->bits_per_coded_sample * st->codec->channels

69
                          * st->codec->sample_rate;

70
    st->codec->block_align = 1;

71


72
    return 0;

73
}

74


75
#define MAX_READ_SIZE 4096

76


77
static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)

78
{

79
    if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)

80
        return AVERROR(EIO);

81
    pkt->flags &= ~AV_PKT_FLAG_CORRUPT;

82
    pkt->stream_index = 0;

83
    return 0;

84
}

85


86
AVInputFormat ff_apc_demuxer = {

87
    .name           = "apc",

88
    .long_name      = NULL_IF_CONFIG_SMALL("CRYO APC"),

89
    .read_probe     = apc_probe,

90
    .read_header    = apc_read_header,

91
    .read_packet    = apc_read_packet,

92
};

93


94