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
186
187
188
189
190
191
192
|
/*
* SMPTE 302M encoder
* Copyright (c) 2010 Google, Inc.
* Copyright (c) 2013 Darryl Wallace <wallacdj@gmail.com>
*
* 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/channel_layout.h"
#include "avcodec.h"
#include "codec_internal.h"
#include "encode.h"
#include "mathops.h"
#include "put_bits.h"
#define AES3_HEADER_LEN 4
typedef struct S302MEncContext {
uint8_t framing_index; /* Set for even channels on multiple of 192 samples */
} S302MEncContext;
static av_cold int s302m_encode_init(AVCodecContext *avctx)
{
S302MEncContext *s = avctx->priv_data;
if (avctx->ch_layout.nb_channels & 1 || avctx->ch_layout.nb_channels > 8) {
av_log(avctx, AV_LOG_ERROR,
"Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n",
avctx->ch_layout.nb_channels);
return AVERROR(EINVAL);
}
switch (avctx->sample_fmt) {
case AV_SAMPLE_FMT_S16:
avctx->bits_per_raw_sample = 16;
break;
case AV_SAMPLE_FMT_S32:
if (avctx->bits_per_raw_sample > 20) {
if (avctx->bits_per_raw_sample > 24)
av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
avctx->bits_per_raw_sample = 24;
} else if (!avctx->bits_per_raw_sample) {
avctx->bits_per_raw_sample = 24;
} else if (avctx->bits_per_raw_sample <= 20) {
avctx->bits_per_raw_sample = 20;
}
}
avctx->frame_size = 0;
avctx->bit_rate = 48000 * avctx->ch_layout.nb_channels *
(avctx->bits_per_raw_sample + 4);
s->framing_index = 0;
return 0;
}
static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt,
const AVFrame *frame, int *got_packet_ptr)
{
S302MEncContext *s = avctx->priv_data;
const int nb_channels = avctx->ch_layout.nb_channels;
const int buf_size = AES3_HEADER_LEN +
(frame->nb_samples * nb_channels *
(avctx->bits_per_raw_sample + 4)) / 8;
int ret, c, channels;
uint8_t *o;
PutBitContext pb;
if (buf_size - AES3_HEADER_LEN > UINT16_MAX) {
av_log(avctx, AV_LOG_ERROR, "number of samples in frame too big\n");
return AVERROR(EINVAL);
}
if ((ret = ff_get_encode_buffer(avctx, avpkt, buf_size, 0)) < 0)
return ret;
o = avpkt->data;
init_put_bits(&pb, o, buf_size);
put_bits(&pb, 16, buf_size - AES3_HEADER_LEN);
put_bits(&pb, 2, (nb_channels - 2) >> 1); // number of channels
put_bits(&pb, 8, 0); // channel ID
put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit)
put_bits(&pb, 4, 0); // alignments
flush_put_bits(&pb);
o += AES3_HEADER_LEN;
if (avctx->bits_per_raw_sample == 24) {
const uint32_t *samples = (uint32_t *)frame->data[0];
for (c = 0; c < frame->nb_samples; c++) {
uint8_t vucf = s->framing_index == 0 ? 0x10: 0;
for (channels = 0; channels < nb_channels; channels += 2) {
o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8];
o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16];
o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24];
o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf;
o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12];
o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20];
o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28];
o += 7;
samples += 2;
}
s->framing_index++;
if (s->framing_index >= 192)
s->framing_index = 0;
}
} else if (avctx->bits_per_raw_sample == 20) {
const uint32_t *samples = (uint32_t *)frame->data[0];
for (c = 0; c < frame->nb_samples; c++) {
uint8_t vucf = s->framing_index == 0 ? 0x80: 0;
for (channels = 0; channels < nb_channels; channels += 2) {
o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12];
o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20];
o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf];
o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12];
o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20];
o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28];
o += 6;
samples += 2;
}
s->framing_index++;
if (s->framing_index >= 192)
s->framing_index = 0;
}
} else if (avctx->bits_per_raw_sample == 16) {
const uint16_t *samples = (uint16_t *)frame->data[0];
for (c = 0; c < frame->nb_samples; c++) {
uint8_t vucf = s->framing_index == 0 ? 0x10 : 0;
for (channels = 0; channels < nb_channels; channels += 2) {
o[0] = ff_reverse[ samples[0] & 0xFF];
o[1] = ff_reverse[(samples[0] & 0xFF00) >> 8];
o[2] = ff_reverse[(samples[1] & 0x0F) << 4] | vucf;
o[3] = ff_reverse[(samples[1] & 0x0FF0) >> 4];
o[4] = ff_reverse[(samples[1] & 0xF000) >> 12];
o += 5;
samples += 2;
}
s->framing_index++;
if (s->framing_index >= 192)
s->framing_index = 0;
}
}
*got_packet_ptr = 1;
return 0;
}
const FFCodec ff_s302m_encoder = {
.p.name = "s302m",
.p.long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
.p.type = AVMEDIA_TYPE_AUDIO,
.p.id = AV_CODEC_ID_S302M,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_EXPERIMENTAL |
AV_CODEC_CAP_VARIABLE_FRAME_SIZE,
.priv_data_size = sizeof(S302MEncContext),
.init = s302m_encode_init,
.encode2 = s302m_encode2_frame,
.p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32,
AV_SAMPLE_FMT_S16,
AV_SAMPLE_FMT_NONE },
.p.supported_samplerates = (const int[]) { 48000, 0 },
/* .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO,
AV_CH_LAYOUT_QUAD,
AV_CH_LAYOUT_5POINT1_BACK,
AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX,
0 }, */
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
|
