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;
88 return AVERROR_INVALIDDATA;
90 init_get_bits(&gb, buf, bit_size);
91 c->object_type = get_object_type(&gb);
92 c->sample_rate = get_sample_rate(&gb, &c->sampling_index);
93 c->chan_config = get_bits(&gb, 4);
94 if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
95 c->channels = ff_mpeg4audio_channels[c->chan_config];
98 if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
99 // check for W6132 Annex YYYY draft MP3onMP4
100 !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {
101 if (c->object_type == AOT_PS)
103 c->ext_object_type = AOT_SBR;
105 c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
106 c->object_type = get_object_type(&gb);
107 if (c->object_type == AOT_ER_BSAC)
108 c->ext_chan_config = get_bits(&gb, 4);
110 c->ext_object_type = AOT_NULL;
111 c->ext_sample_rate = 0;
113 specific_config_bitindex = get_bits_count(&gb);
115 if (c->object_type == AOT_ALS) {
117 if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
118 skip_bits_long(&gb, 24);
120 specific_config_bitindex = get_bits_count(&gb);
122 if (parse_config_ALS(&gb, c))
126 if (c->ext_object_type != AOT_SBR && sync_extension) {
127 while (get_bits_left(&gb) > 15) {
128 if (show_bits(&gb, 11) == 0x2b7) { // sync extension
130 c->ext_object_type = get_object_type(&gb);
131 if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) {
132 c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
133 if (c->ext_sample_rate == c->sample_rate)
136 if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)
137 c->ps = get_bits1(&gb);
140 get_bits1(&gb); // skip 1 bit
147 //Limit implicit PS to the HE-AACv2 Profile
148 if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
151 return specific_config_bitindex;
154 static av_always_inline unsigned int copy_bits(PutBitContext *pb,
158 unsigned int el = get_bits(gb, bits);
159 put_bits(pb, bits, el);
163 int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
165 int five_bit_ch, four_bit_ch, comment_size, bits;
166 int offset = put_bits_count(pb);
168 copy_bits(pb, gb, 10); //Tag, Object Type, Frequency
169 five_bit_ch = copy_bits(pb, gb, 4); //Front
170 five_bit_ch += copy_bits(pb, gb, 4); //Side
171 five_bit_ch += copy_bits(pb, gb, 4); //Back
172 four_bit_ch = copy_bits(pb, gb, 2); //LFE
173 four_bit_ch += copy_bits(pb, gb, 3); //Data
174 five_bit_ch += copy_bits(pb, gb, 4); //Coupling
175 if (copy_bits(pb, gb, 1)) //Mono Mixdown
176 copy_bits(pb, gb, 4);
177 if (copy_bits(pb, gb, 1)) //Stereo Mixdown
178 copy_bits(pb, gb, 4);
179 if (copy_bits(pb, gb, 1)) //Matrix Mixdown
180 copy_bits(pb, gb, 3);
181 for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
182 copy_bits(pb, gb, 16);
184 copy_bits(pb, gb, bits);
185 avpriv_align_put_bits(pb);
187 comment_size = copy_bits(pb, gb, 8);
188 for (; comment_size > 0; comment_size--)
189 copy_bits(pb, gb, 8);
191 return put_bits_count(pb) - offset;