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
193
194
195
196
197
198
199
200
|
/*
* MPEG-4 Audio common code
* Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
* Copyright (c) 2009 Alex Converse <alex.converse@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 "get_bits.h"
#include "put_bits.h"
#include "mpeg4audio.h"
/**
* Parse MPEG-4 audio configuration for ALS object type.
* @param[in] gb bit reader context
* @param[in] c MPEG4AudioConfig structure to fill
* @return on success 0 is returned, otherwise a value < 0
*/
static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
{
if (get_bits_left(gb) < 112)
return -1;
if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
return -1;
// override AudioSpecificConfig channel configuration and sample rate
// which are buggy in old ALS conformance files
c->sample_rate = get_bits_long(gb, 32);
if (c->sample_rate <= 0) {
av_log(NULL, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate);
return AVERROR_INVALIDDATA;
}
// skip number of samples
skip_bits_long(gb, 32);
// read number of channels
c->chan_config = 0;
c->channels = get_bits(gb, 16) + 1;
return 0;
}
/* XXX: make sure to update the copies in the different encoders if you change
* this table */
const int avpriv_mpeg4audio_sample_rates[16] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350
};
const uint8_t ff_mpeg4audio_channels[8] = {
0, 1, 2, 3, 4, 5, 6, 8
};
static inline int get_object_type(GetBitContext *gb)
{
int object_type = get_bits(gb, 5);
if (object_type == AOT_ESCAPE)
object_type = 32 + get_bits(gb, 6);
return object_type;
}
static inline int get_sample_rate(GetBitContext *gb, int *index)
{
*index = get_bits(gb, 4);
return *index == 0x0f ? get_bits(gb, 24) :
avpriv_mpeg4audio_sample_rates[*index];
}
int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
int bit_size, int sync_extension)
{
GetBitContext gb;
int specific_config_bitindex, ret;
if (bit_size <= 0)
return AVERROR_INVALIDDATA;
ret = init_get_bits(&gb, buf, bit_size);
if (ret < 0)
return ret;
c->object_type = get_object_type(&gb);
c->sample_rate = get_sample_rate(&gb, &c->sampling_index);
c->chan_config = get_bits(&gb, 4);
if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
c->channels = ff_mpeg4audio_channels[c->chan_config];
c->sbr = -1;
c->ps = -1;
if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
// check for W6132 Annex YYYY draft MP3onMP4
!(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {
if (c->object_type == AOT_PS)
c->ps = 1;
c->ext_object_type = AOT_SBR;
c->sbr = 1;
c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
c->object_type = get_object_type(&gb);
if (c->object_type == AOT_ER_BSAC)
c->ext_chan_config = get_bits(&gb, 4);
} else {
c->ext_object_type = AOT_NULL;
c->ext_sample_rate = 0;
}
specific_config_bitindex = get_bits_count(&gb);
if (c->object_type == AOT_ALS) {
skip_bits(&gb, 5);
if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
skip_bits_long(&gb, 24);
specific_config_bitindex = get_bits_count(&gb);
if (parse_config_ALS(&gb, c))
return -1;
}
if (c->ext_object_type != AOT_SBR && sync_extension) {
while (get_bits_left(&gb) > 15) {
if (show_bits(&gb, 11) == 0x2b7) { // sync extension
get_bits(&gb, 11);
c->ext_object_type = get_object_type(&gb);
if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) {
c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
if (c->ext_sample_rate == c->sample_rate)
c->sbr = -1;
}
if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)
c->ps = get_bits1(&gb);
break;
} else
get_bits1(&gb); // skip 1 bit
}
}
//PS requires SBR
if (!c->sbr)
c->ps = 0;
//Limit implicit PS to the HE-AACv2 Profile
if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
c->ps = 0;
return specific_config_bitindex;
}
static av_always_inline unsigned int copy_bits(PutBitContext *pb,
GetBitContext *gb,
int bits)
{
unsigned int el = get_bits(gb, bits);
put_bits(pb, bits, el);
return el;
}
int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
{
int five_bit_ch, four_bit_ch, comment_size, bits;
int offset = put_bits_count(pb);
copy_bits(pb, gb, 10); //Tag, Object Type, Frequency
five_bit_ch = copy_bits(pb, gb, 4); //Front
five_bit_ch += copy_bits(pb, gb, 4); //Side
five_bit_ch += copy_bits(pb, gb, 4); //Back
four_bit_ch = copy_bits(pb, gb, 2); //LFE
four_bit_ch += copy_bits(pb, gb, 3); //Data
five_bit_ch += copy_bits(pb, gb, 4); //Coupling
if (copy_bits(pb, gb, 1)) //Mono Mixdown
copy_bits(pb, gb, 4);
if (copy_bits(pb, gb, 1)) //Stereo Mixdown
copy_bits(pb, gb, 4);
if (copy_bits(pb, gb, 1)) //Matrix Mixdown
copy_bits(pb, gb, 3);
for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
copy_bits(pb, gb, 16);
if (bits)
copy_bits(pb, gb, bits);
avpriv_align_put_bits(pb);
align_get_bits(gb);
comment_size = copy_bits(pb, gb, 8);
for (; comment_size > 0; comment_size--)
copy_bits(pb, gb, 8);
return put_bits_count(pb) - offset;
}
|
