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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* ADX ADPCM codecs
* Copyright (c) 2001,2003 BERO
*
* 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 "avcodec.h"
#include "adx.h"
#include "get_bits.h"
/**
* @file
* SEGA CRI adx codecs.
*
* Reference documents:
* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
*/
static av_cold int adx_decode_init(AVCodecContext *avctx)
{
ADXContext *c = avctx->priv_data;
int ret, header_size;
if (avctx->extradata_size >= 24) {
if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
avctx->extradata_size, &header_size,
c->coeff)) < 0) {
av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
return AVERROR_INVALIDDATA;
}
c->channels = avctx->channels;
c->header_parsed = 1;
}
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
avcodec_get_frame_defaults(&c->frame);
avctx->coded_frame = &c->frame;
return 0;
}
/**
* Decode 32 samples from 18 bytes.
*
* A 16-bit scalar value is applied to 32 residuals, which then have a
* 2nd-order LPC filter applied to it to form the output signal for a single
* channel.
*/
static int adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch)
{
ADXChannelState *prev = &c->prev[ch];
GetBitContext gb;
int scale = AV_RB16(in);
int i;
int s0, s1, s2, d;
/* check if this is an EOF packet */
if (scale & 0x8000)
return -1;
init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
s1 = prev->s1;
s2 = prev->s2;
for (i = 0; i < BLOCK_SAMPLES; i++) {
d = get_sbits(&gb, 4);
s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
s2 = s1;
s1 = av_clip_int16(s0);
*out = s1;
out += c->channels;
}
prev->s1 = s1;
prev->s2 = s2;
return 0;
}
static int adx_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
int buf_size = avpkt->size;
ADXContext *c = avctx->priv_data;
int16_t *samples;
const uint8_t *buf = avpkt->data;
int num_blocks, ch, ret;
if (c->eof) {
*got_frame_ptr = 0;
return buf_size;
}
if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
int header_size;
if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
c->coeff)) < 0) {
av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
return AVERROR_INVALIDDATA;
}
c->channels = avctx->channels;
c->header_parsed = 1;
if (buf_size < header_size)
return AVERROR_INVALIDDATA;
buf += header_size;
buf_size -= header_size;
}
if (!c->header_parsed)
return AVERROR_INVALIDDATA;
/* calculate number of blocks in the packet */
num_blocks = buf_size / (BLOCK_SIZE * c->channels);
/* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
packet */
if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
c->eof = 1;
*got_frame_ptr = 0;
return avpkt->size;
}
return AVERROR_INVALIDDATA;
}
/* get output buffer */
c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;
if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
samples = (int16_t *)c->frame.data[0];
while (num_blocks--) {
for (ch = 0; ch < c->channels; ch++) {
if (adx_decode(c, samples + ch, buf, ch)) {
c->eof = 1;
buf = avpkt->data + avpkt->size;
break;
}
buf_size -= BLOCK_SIZE;
buf += BLOCK_SIZE;
}
samples += BLOCK_SAMPLES * c->channels;
}
*got_frame_ptr = 1;
*(AVFrame *)data = c->frame;
return buf - avpkt->data;
}
static void adx_decode_flush(AVCodecContext *avctx)
{
ADXContext *c = avctx->priv_data;
memset(c->prev, 0, sizeof(c->prev));
c->eof = 0;
}
AVCodec ff_adpcm_adx_decoder = {
.name = "adpcm_adx",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_ADPCM_ADX,
.priv_data_size = sizeof(ADXContext),
.init = adx_decode_init,
.decode = adx_decode_frame,
.flush = adx_decode_flush,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
};
|
