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
|
/*
* MIDI Sample Dump Standard format demuxer
* Copyright (c) 2017 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
typedef struct SDSContext {
uint8_t data[120];
int bit_depth;
int size;
void (*read_block)(const uint8_t *src, uint32_t *dst);
} SDSContext;
static int sds_probe(const AVProbeData *p)
{
if (AV_RB32(p->buf) == 0xF07E0001 && p->buf[20] == 0xF7 &&
p->buf[6] >= 8 && p->buf[6] <= 28)
return AVPROBE_SCORE_EXTENSION;
return 0;
}
static void byte2_read(const uint8_t *src, uint32_t *dst)
{
int i;
for (i = 0; i < 120; i += 2) {
unsigned sample = (src[i + 0] << 25) + (src[i + 1] << 18);
dst[i / 2] = sample;
}
}
static void byte3_read(const uint8_t *src, uint32_t *dst)
{
int i;
for (i = 0; i < 120; i += 3) {
unsigned sample;
sample = (src[i + 0] << 25) | (src[i + 1] << 18) | (src[i + 2] << 11);
dst[i / 3] = sample;
}
}
static void byte4_read(const uint8_t *src, uint32_t *dst)
{
int i;
for (i = 0; i < 120; i += 4) {
unsigned sample;
sample = (src[i + 0] << 25) | (src[i + 1] << 18) | (src[i + 2] << 11) | (src[i + 3] << 4);
dst[i / 4] = sample;
}
}
#define SDS_3BYTE_TO_INT_DECODE(x) (((x) & 0x7F) | (((x) & 0x7F00) >> 1) | (((x) & 0x7F0000) >> 2))
static int sds_read_header(AVFormatContext *ctx)
{
SDSContext *s = ctx->priv_data;
unsigned sample_period;
AVIOContext *pb = ctx->pb;
AVStream *st;
st = avformat_new_stream(ctx, NULL);
if (!st)
return AVERROR(ENOMEM);
avio_skip(pb, 4);
avio_skip(pb, 2);
s->bit_depth = avio_r8(pb);
if (s->bit_depth < 8 || s->bit_depth > 28)
return AVERROR_INVALIDDATA;
if (s->bit_depth < 14) {
s->read_block = byte2_read;
s->size = 60 * 4;
} else if (s->bit_depth < 21) {
s->read_block = byte3_read;
s->size = 40 * 4;
} else {
s->read_block = byte4_read;
s->size = 30 * 4;
}
st->codecpar->codec_id = AV_CODEC_ID_PCM_U32LE;
sample_period = avio_rl24(pb);
sample_period = SDS_3BYTE_TO_INT_DECODE(sample_period);
avio_skip(pb, 11);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->channels = 1;
st->codecpar->sample_rate = sample_period ? 1000000000 / sample_period : 16000;
st->duration = (avio_size(pb) - 21) / (127) * s->size / 4;
avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
return 0;
}
static int sds_read_packet(AVFormatContext *ctx, AVPacket *pkt)
{
SDSContext *s = ctx->priv_data;
AVIOContext *pb = ctx->pb;
int64_t pos;
int ret;
if (avio_feof(pb))
return AVERROR_EOF;
pos = avio_tell(pb);
if (avio_rb16(pb) != 0xF07E)
return AVERROR_INVALIDDATA;
avio_skip(pb, 3);
ret = av_new_packet(pkt, s->size);
if (ret < 0)
return ret;
ret = avio_read(pb, s->data, 120);
s->read_block(s->data, (uint32_t *)pkt->data);
avio_skip(pb, 1); // checksum
if (avio_r8(pb) != 0xF7)
return AVERROR_INVALIDDATA;
pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
pkt->stream_index = 0;
pkt->pos = pos;
return ret;
}
AVInputFormat ff_sds_demuxer = {
.name = "sds",
.long_name = NULL_IF_CONFIG_SMALL("MIDI Sample Dump Standard"),
.priv_data_size = sizeof(SDSContext),
.read_probe = sds_probe,
.read_header = sds_read_header,
.read_packet = sds_read_packet,
.extensions = "sds",
.flags = AVFMT_GENERIC_INDEX,
};
|