summaryrefslogtreecommitdiffstats
path: root/libavcodec/s302m.c
blob: 76fab59e9a755edd219ebacb0b5da2c8742d6cad (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
 * SMPTE 302M decoder
 * Copyright (c) 2008 Laurent Aimar <fenrir@videolan.org>
 * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "avcodec.h"
#include "internal.h"
#include "mathops.h"

#define AES3_HEADER_LEN 4

typedef struct S302MDecodeContext {
    AVFrame frame;
} S302MDecodeContext;

static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf,
                                    int buf_size)
{
    uint32_t h;
    int frame_size, channels, bits;

    if (buf_size <= AES3_HEADER_LEN) {
        av_log(avctx, AV_LOG_ERROR, "frame is too short\n");
        return AVERROR_INVALIDDATA;
    }

    /*
     * AES3 header :
     * size:            16
     * number channels   2
     * channel_id        8
     * bits per samples  2
     * alignments        4
     */

    h = AV_RB32(buf);
    frame_size =  (h >> 16) & 0xffff;
    channels   = ((h >> 14) & 0x0003) * 2 +  2;
    bits       = ((h >>  4) & 0x0003) * 4 + 16;

    if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) {
        av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n");
        return AVERROR_INVALIDDATA;
    }

    /* Set output properties */
    avctx->bits_per_coded_sample = bits;
    if (bits > 16)
        avctx->sample_fmt = AV_SAMPLE_FMT_S32;
    else
        avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    avctx->channels    = channels;
    avctx->sample_rate = 48000;
    avctx->bit_rate    = 48000 * avctx->channels * (avctx->bits_per_coded_sample + 4) +
                         32 * (48000 / (buf_size * 8 /
                                        (avctx->channels *
                                         (avctx->bits_per_coded_sample + 4))));

    return frame_size;
}

static int s302m_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_frame_ptr, AVPacket *avpkt)
{
    S302MDecodeContext *s = avctx->priv_data;
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;
    int block_size, ret;

    int frame_size = s302m_parse_frame_header(avctx, buf, buf_size);
    if (frame_size < 0)
        return frame_size;

    buf_size -= AES3_HEADER_LEN;
    buf      += AES3_HEADER_LEN;

    /* get output buffer */
    block_size = (avctx->bits_per_coded_sample + 4) / 4;
    s->frame.nb_samples = 2 * (buf_size / block_size) / avctx->channels;
    if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return ret;
    }

    buf_size = (s->frame.nb_samples * avctx->channels / 2) * block_size;

    if (avctx->bits_per_coded_sample == 24) {
        uint32_t *o = (uint32_t *)s->frame.data[0];
        for (; buf_size > 6; buf_size -= 7) {
            *o++ = (ff_reverse[buf[2]]        << 24) |
                   (ff_reverse[buf[1]]        << 16) |
                   (ff_reverse[buf[0]]        <<  8);
            *o++ = (ff_reverse[buf[6] & 0xf0] << 28) |
                   (ff_reverse[buf[5]]        << 20) |
                   (ff_reverse[buf[4]]        << 12) |
                   (ff_reverse[buf[3] & 0x0f] <<  4);
            buf += 7;
        }
    } else if (avctx->bits_per_coded_sample == 20) {
        uint32_t *o = (uint32_t *)s->frame.data[0];
        for (; buf_size > 5; buf_size -= 6) {
            *o++ = (ff_reverse[buf[2] & 0xf0] << 28) |
                   (ff_reverse[buf[1]]        << 20) |
                   (ff_reverse[buf[0]]        << 12);
            *o++ = (ff_reverse[buf[5] & 0xf0] << 28) |
                   (ff_reverse[buf[4]]        << 20) |
                   (ff_reverse[buf[3]]        << 12);
            buf += 6;
        }
    } else {
        uint16_t *o = (uint16_t *)s->frame.data[0];
        for (; buf_size > 4; buf_size -= 5) {
            *o++ = (ff_reverse[buf[1]]        <<  8) |
                    ff_reverse[buf[0]];
            *o++ = (ff_reverse[buf[4] & 0xf0] << 12) |
                   (ff_reverse[buf[3]]        <<  4) |
                   (ff_reverse[buf[2]]        >>  4);
            buf += 5;
        }
    }

    *got_frame_ptr   = 1;
    *(AVFrame *)data = s->frame;

    return avpkt->size;
}

static int s302m_decode_init(AVCodecContext *avctx)
{
    S302MDecodeContext *s = avctx->priv_data;

    avcodec_get_frame_defaults(&s->frame);
    avctx->coded_frame = &s->frame;

    return 0;
}


AVCodec ff_s302m_decoder = {
    .name           = "s302m",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_S302M,
    .priv_data_size = sizeof(S302MDecodeContext),
    .init           = s302m_decode_init,
    .decode         = s302m_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
};
OpenPOWER on IntegriCloud