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
|
/*
* Westwood SNDx codecs
* Copyright (c) 2005 Konstantin Shishkov
*
* 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 "avcodec.h"
/**
* @file ws-snd.c
* Westwood SNDx codecs.
*
* Reference documents about VQA format and its audio codecs
* can be found here:
* http://www.multimedia.cx
*/
static const char ws_adpcm_2bit[] = { -2, -1, 0, 1};
static const char ws_adpcm_4bit[] = {
-9, -8, -6, -5, -4, -3, -2, -1,
0, 1, 2, 3, 4, 5, 6, 8 };
#define CLIP8(a) if(a>127)a=127;if(a<-128)a=-128;
static av_cold int ws_snd_decode_init(AVCodecContext * avctx)
{
// WSSNDContext *c = avctx->priv_data;
return 0;
}
static int ws_snd_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
// WSSNDContext *c = avctx->priv_data;
int in_size, out_size;
int sample = 0;
int i;
short *samples = data;
if (!buf_size)
return 0;
out_size = AV_RL16(&buf[0]);
*data_size = out_size * 2;
in_size = AV_RL16(&buf[2]);
buf += 4;
if (out_size > *data_size) {
av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");
return -1;
}
if (in_size > buf_size) {
av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
return -1;
}
if (in_size == out_size) {
for (i = 0; i < out_size; i++)
*samples++ = (*buf++ - 0x80) << 8;
return buf_size;
}
while (out_size > 0) {
int code;
uint8_t count;
code = (*buf) >> 6;
count = (*buf) & 0x3F;
buf++;
switch(code) {
case 0: /* ADPCM 2-bit */
for (count++; count > 0; count--) {
code = *buf++;
sample += ws_adpcm_2bit[code & 0x3];
CLIP8(sample);
*samples++ = sample << 8;
sample += ws_adpcm_2bit[(code >> 2) & 0x3];
CLIP8(sample);
*samples++ = sample << 8;
sample += ws_adpcm_2bit[(code >> 4) & 0x3];
CLIP8(sample);
*samples++ = sample << 8;
sample += ws_adpcm_2bit[(code >> 6) & 0x3];
CLIP8(sample);
*samples++ = sample << 8;
out_size -= 4;
}
break;
case 1: /* ADPCM 4-bit */
for (count++; count > 0; count--) {
code = *buf++;
sample += ws_adpcm_4bit[code & 0xF];
CLIP8(sample);
*samples++ = sample << 8;
sample += ws_adpcm_4bit[code >> 4];
CLIP8(sample);
*samples++ = sample << 8;
out_size -= 2;
}
break;
case 2: /* no compression */
if (count & 0x20) { /* big delta */
char t;
t = count;
t <<= 3;
sample += t >> 3;
*samples++ = sample << 8;
out_size--;
} else { /* copy */
for (count++; count > 0; count--) {
*samples++ = (*buf++ - 0x80) << 8;
out_size--;
}
sample = buf[-1] - 0x80;
}
break;
default: /* run */
for(count++; count > 0; count--) {
*samples++ = sample << 8;
out_size--;
}
}
}
return buf_size;
}
AVCodec ws_snd1_decoder = {
"ws_snd1",
CODEC_TYPE_AUDIO,
CODEC_ID_WESTWOOD_SND1,
0,
ws_snd_decode_init,
NULL,
NULL,
ws_snd_decode_frame,
};
|
