2 * MPEG-4 Audio common code
3 * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
4 * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "mpeg4audio.h"
28 * Parse MPEG-4 audio configuration for ALS object type.
29 * @param[in] gb bit reader context
30 * @param[in] c MPEG4AudioConfig structure to fill
31 * @return on success 0 is returned, otherwise a value < 0
33 static int parse_config_ALS(GetBitContext
*gb
, MPEG4AudioConfig
*c
)
35 if (get_bits_left(gb
) < 112)
38 if (get_bits_long(gb
, 32) != MKBETAG('A','L','S','\0'))
41 // override AudioSpecificConfig channel configuration and sample rate
42 // which are buggy in old ALS conformance files
43 c
->sample_rate
= get_bits_long(gb
, 32);
45 // skip number of samples
46 skip_bits_long(gb
, 32);
48 // read number of channels
50 c
->channels
= get_bits(gb
, 16) + 1;
55 /* XXX: make sure to update the copies in the different encoders if you change
57 const int avpriv_mpeg4audio_sample_rates
[16] = {
58 96000, 88200, 64000, 48000, 44100, 32000,
59 24000, 22050, 16000, 12000, 11025, 8000, 7350
62 const uint8_t ff_mpeg4audio_channels
[8] = {
63 0, 1, 2, 3, 4, 5, 6, 8
66 static inline int get_object_type(GetBitContext
*gb
)
68 int object_type
= get_bits(gb
, 5);
69 if (object_type
== AOT_ESCAPE
)
70 object_type
= 32 + get_bits(gb
, 6);
74 static inline int get_sample_rate(GetBitContext
*gb
, int *index
)
76 *index
= get_bits(gb
, 4);
77 return *index
== 0x0f ? get_bits(gb
, 24) :
78 avpriv_mpeg4audio_sample_rates
[*index
];
81 int avpriv_mpeg4audio_get_config(MPEG4AudioConfig
*c
, const uint8_t *buf
,
82 int bit_size
, int sync_extension
)
85 int specific_config_bitindex
;
87 if (bit_size
<= 0 || init_get_bits(&gb
, buf
, bit_size
) < 0)
88 return AVERROR_INVALIDDATA
;
89 c
->object_type
= get_object_type(&gb
);
90 c
->sample_rate
= get_sample_rate(&gb
, &c
->sampling_index
);
91 c
->chan_config
= get_bits(&gb
, 4);
92 if (c
->chan_config
< FF_ARRAY_ELEMS(ff_mpeg4audio_channels
))
93 c
->channels
= ff_mpeg4audio_channels
[c
->chan_config
];
96 if (c
->object_type
== AOT_SBR
|| (c
->object_type
== AOT_PS
&&
97 // check for W6132 Annex YYYY draft MP3onMP4
98 !(show_bits(&gb
, 3) & 0x03 && !(show_bits(&gb
, 9) & 0x3F)))) {
99 if (c
->object_type
== AOT_PS
)
101 c
->ext_object_type
= AOT_SBR
;
103 c
->ext_sample_rate
= get_sample_rate(&gb
, &c
->ext_sampling_index
);
104 c
->object_type
= get_object_type(&gb
);
105 if (c
->object_type
== AOT_ER_BSAC
)
106 c
->ext_chan_config
= get_bits(&gb
, 4);
108 c
->ext_object_type
= AOT_NULL
;
109 c
->ext_sample_rate
= 0;
111 specific_config_bitindex
= get_bits_count(&gb
);
113 if (c
->object_type
== AOT_ALS
) {
115 if (show_bits_long(&gb
, 24) != MKBETAG('\0','A','L','S'))
116 skip_bits_long(&gb
, 24);
118 specific_config_bitindex
= get_bits_count(&gb
);
120 if (parse_config_ALS(&gb
, c
))
124 if (c
->ext_object_type
!= AOT_SBR
&& sync_extension
) {
125 while (get_bits_left(&gb
) > 15) {
126 if (show_bits(&gb
, 11) == 0x2b7) { // sync extension
128 c
->ext_object_type
= get_object_type(&gb
);
129 if (c
->ext_object_type
== AOT_SBR
&& (c
->sbr
= get_bits1(&gb
)) == 1) {
130 c
->ext_sample_rate
= get_sample_rate(&gb
, &c
->ext_sampling_index
);
131 if (c
->ext_sample_rate
== c
->sample_rate
)
134 if (get_bits_left(&gb
) > 11 && get_bits(&gb
, 11) == 0x548)
135 c
->ps
= get_bits1(&gb
);
138 get_bits1(&gb
); // skip 1 bit
145 //Limit implicit PS to the HE-AACv2 Profile
146 if ((c
->ps
== -1 && c
->object_type
!= AOT_AAC_LC
) || c
->channels
& ~0x01)
149 return specific_config_bitindex
;
152 static av_always_inline
unsigned int copy_bits(PutBitContext
*pb
,
156 unsigned int el
= get_bits(gb
, bits
);
157 put_bits(pb
, bits
, el
);
161 int avpriv_copy_pce_data(PutBitContext
*pb
, GetBitContext
*gb
)
163 int five_bit_ch
, four_bit_ch
, comment_size
, bits
;
164 int offset
= put_bits_count(pb
);
166 copy_bits(pb
, gb
, 10); //Tag, Object Type, Frequency
167 five_bit_ch
= copy_bits(pb
, gb
, 4); //Front
168 five_bit_ch
+= copy_bits(pb
, gb
, 4); //Side
169 five_bit_ch
+= copy_bits(pb
, gb
, 4); //Back
170 four_bit_ch
= copy_bits(pb
, gb
, 2); //LFE
171 four_bit_ch
+= copy_bits(pb
, gb
, 3); //Data
172 five_bit_ch
+= copy_bits(pb
, gb
, 4); //Coupling
173 if (copy_bits(pb
, gb
, 1)) //Mono Mixdown
174 copy_bits(pb
, gb
, 4);
175 if (copy_bits(pb
, gb
, 1)) //Stereo Mixdown
176 copy_bits(pb
, gb
, 4);
177 if (copy_bits(pb
, gb
, 1)) //Matrix Mixdown
178 copy_bits(pb
, gb
, 3);
179 for (bits
= five_bit_ch
*5+four_bit_ch
*4; bits
> 16; bits
-= 16)
180 copy_bits(pb
, gb
, 16);
182 copy_bits(pb
, gb
, bits
);
183 avpriv_align_put_bits(pb
);
185 comment_size
= copy_bits(pb
, gb
, 8);
186 for (; comment_size
> 0; comment_size
--)
187 copy_bits(pb
, gb
, 8);
189 return put_bits_count(pb
) - offset
;