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
|
/*
* ADTS muxer.
* Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
* Mans Rullgard <mans@mansr.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 "libavcodec/bitstream.h"
#include "libavcodec/internal.h"
#include "avformat.h"
#define ADTS_HEADER_SIZE 7
typedef struct {
int write_adts;
int objecttype;
int sample_rate_index;
int channel_conf;
} ADTSContext;
static int decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size)
{
GetBitContext gb;
init_get_bits(&gb, buf, size * 8);
adts->objecttype = get_bits(&gb, 5) - 1;
adts->sample_rate_index = get_bits(&gb, 4);
adts->channel_conf = get_bits(&gb, 4);
if (adts->objecttype > 3U) {
av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
return -1;
}
if (adts->sample_rate_index == 15) {
av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
return -1;
}
if (adts->channel_conf == 0) {
ff_log_missing_feature(s, "PCE based channel configuration", 0);
return -1;
}
if (get_bits(&gb, 1)) {
av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
return -1;
}
if (get_bits(&gb, 1)) {
av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
return -1;
}
if (get_bits(&gb, 1)) {
ff_log_missing_feature(s, "Signaled SBR or PS", 0);
return -1;
}
adts->write_adts = 1;
return 0;
}
static int adts_write_header(AVFormatContext *s)
{
ADTSContext *adts = s->priv_data;
AVCodecContext *avc = s->streams[0]->codec;
if(avc->extradata_size > 0 &&
decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0)
return -1;
return 0;
}
static int adts_write_frame_header(AVFormatContext *s, int size)
{
ADTSContext *ctx = s->priv_data;
PutBitContext pb;
uint8_t buf[ADTS_HEADER_SIZE];
init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
/* adts_fixed_header */
put_bits(&pb, 12, 0xfff); /* syncword */
put_bits(&pb, 1, 0); /* ID */
put_bits(&pb, 2, 0); /* layer */
put_bits(&pb, 1, 1); /* protection_absent */
put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
put_bits(&pb, 4, ctx->sample_rate_index);
put_bits(&pb, 1, 0); /* private_bit */
put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
put_bits(&pb, 1, 0); /* original_copy */
put_bits(&pb, 1, 0); /* home */
/* adts_variable_header */
put_bits(&pb, 1, 0); /* copyright_identification_bit */
put_bits(&pb, 1, 0); /* copyright_identification_start */
put_bits(&pb, 13, ADTS_HEADER_SIZE + size); /* aac_frame_length */
put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */
put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */
flush_put_bits(&pb);
put_buffer(s->pb, buf, ADTS_HEADER_SIZE);
return 0;
}
static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
{
ADTSContext *adts = s->priv_data;
ByteIOContext *pb = s->pb;
if (!pkt->size)
return 0;
if(adts->write_adts)
adts_write_frame_header(s, pkt->size);
put_buffer(pb, pkt->data, pkt->size);
put_flush_packet(pb);
return 0;
}
AVOutputFormat adts_muxer = {
"adts",
NULL_IF_CONFIG_SMALL("ADTS AAC"),
"audio/aac",
"aac",
sizeof(ADTSContext),
CODEC_ID_AAC,
CODEC_ID_NONE,
adts_write_header,
adts_write_packet,
};
|
