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
|
/*
* QOA decoder
*
* 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"
#include "codec_internal.h"
#include "decode.h"
#include "get_bits.h"
#include "bytestream.h"
#include "mathops.h"
#define QOA_SLICE_LEN 20
#define QOA_LMS_LEN 4
typedef struct QOAChannel {
int history[QOA_LMS_LEN];
int weights[QOA_LMS_LEN];
} QOAChannel;
typedef struct QOAContext {
QOAChannel ch[256];
} QOAContext;
static const int16_t qoa_dequant_tab[16][8] = {
{ 1, -1, 3, -3, 5, -5, 7, -7},
{ 5, -5, 18, -18, 32, -32, 49, -49},
{ 16, -16, 53, -53, 95, -95, 147, -147},
{ 34, -34, 113, -113, 203, -203, 315, -315},
{ 63, -63, 210, -210, 378, -378, 588, -588},
{ 104, -104, 345, -345, 621, -621, 966, -966},
{ 158, -158, 528, -528, 950, -950, 1477, -1477},
{ 228, -228, 760, -760, 1368, -1368, 2128, -2128},
{ 316, -316, 1053, -1053, 1895, -1895, 2947, -2947},
{ 422, -422, 1405, -1405, 2529, -2529, 3934, -3934},
{ 548, -548, 1828, -1828, 3290, -3290, 5117, -5117},
{ 696, -696, 2320, -2320, 4176, -4176, 6496, -6496},
{ 868, -868, 2893, -2893, 5207, -5207, 8099, -8099},
{1064, -1064, 3548, -3548, 6386, -6386, 9933, -9933},
{1286, -1286, 4288, -4288, 7718, -7718, 12005, -12005},
{1536, -1536, 5120, -5120, 9216, -9216, 14336, -14336},
};
static av_cold int qoa_decode_init(AVCodecContext *avctx)
{
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
return 0;
}
static int qoa_lms_predict(QOAChannel *lms)
{
int prediction = 0;
for (int i = 0; i < QOA_LMS_LEN; i++)
prediction += (unsigned)lms->weights[i] * lms->history[i];
return prediction >> 13;
}
static void qoa_lms_update(QOAChannel *lms, int sample, int residual)
{
int delta = residual >> 4;
for (int i = 0; i < QOA_LMS_LEN; i++)
lms->weights[i] += lms->history[i] < 0 ? -delta : delta;
for (int i = 0; i < QOA_LMS_LEN-1; i++)
lms->history[i] = lms->history[i+1];
lms->history[QOA_LMS_LEN-1] = sample;
}
static int qoa_decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame_ptr, AVPacket *avpkt)
{
QOAContext *s = avctx->priv_data;
int ret, frame_size, nb_channels, sample_rate;
GetByteContext gb;
int16_t *samples;
bytestream2_init(&gb, avpkt->data, avpkt->size);
nb_channels = bytestream2_get_byte(&gb);
sample_rate = bytestream2_get_be24(&gb);
if (!sample_rate || !nb_channels)
return AVERROR_INVALIDDATA;
if (nb_channels != avctx->ch_layout.nb_channels) {
av_channel_layout_uninit(&avctx->ch_layout);
av_channel_layout_default(&avctx->ch_layout, nb_channels);
if ((ret = av_channel_layout_copy(&frame->ch_layout, &avctx->ch_layout)) < 0)
return ret;
}
frame->sample_rate = avctx->sample_rate = sample_rate;
frame->nb_samples = bytestream2_get_be16(&gb);
frame_size = bytestream2_get_be16(&gb);
if (frame_size > avpkt->size)
return AVERROR_INVALIDDATA;
if (avpkt->size < 8 + QOA_LMS_LEN * 4 * nb_channels +
8LL * ((frame->nb_samples + QOA_SLICE_LEN - 1) / QOA_SLICE_LEN) * nb_channels)
return AVERROR_INVALIDDATA;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
samples = (int16_t *)frame->data[0];
for (int ch = 0; ch < nb_channels; ch++) {
QOAChannel *qch = &s->ch[ch];
for (int n = 0; n < QOA_LMS_LEN; n++)
qch->history[n] = sign_extend(bytestream2_get_be16u(&gb), 16);
for (int n = 0; n < QOA_LMS_LEN; n++)
qch->weights[n] = sign_extend(bytestream2_get_be16u(&gb), 16);
}
for (int sample_index = 0; sample_index < frame->nb_samples;
sample_index += QOA_SLICE_LEN) {
for (int ch = 0; ch < nb_channels; ch++) {
QOAChannel *lms = &s->ch[ch];
uint64_t slice = bytestream2_get_be64u(&gb);
int scalefactor = (slice >> 60) & 0xf;
int slice_start = sample_index * nb_channels + ch;
int slice_end = av_clip(sample_index + QOA_SLICE_LEN, 0, frame->nb_samples) * nb_channels + ch;
for (int si = slice_start; si < slice_end; si += nb_channels) {
int predicted = qoa_lms_predict(lms);
int quantized = (slice >> 57) & 0x7;
int dequantized = qoa_dequant_tab[scalefactor][quantized];
int reconstructed = av_clip_int16(predicted + dequantized);
samples[si] = reconstructed;
slice <<= 3;
qoa_lms_update(lms, reconstructed, dequantized);
}
}
}
*got_frame_ptr = 1;
return avpkt->size;
}
const FFCodec ff_qoa_decoder = {
.p.name = "qoa",
CODEC_LONG_NAME("QOA (Quite OK Audio)"),
.p.type = AVMEDIA_TYPE_AUDIO,
.p.id = AV_CODEC_ID_QOA,
.priv_data_size = sizeof(QOAContext),
.init = qoa_decode_init,
FF_CODEC_DECODE_CB(qoa_decode_frame),
.p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
AV_SAMPLE_FMT_NONE },
};
|
