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, void *logctx)
35 if (get_bits_left(gb) < 112)
36 return AVERROR_INVALIDDATA;
38 if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
39 return AVERROR_INVALIDDATA;
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 if (c->sample_rate <= 0) {
46 av_log(logctx, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate);
47 return AVERROR_INVALIDDATA;
50 // skip number of samples
51 skip_bits_long(gb, 32);
53 // read number of channels
55 c->channels = get_bits(gb, 16) + 1;
60 /* XXX: make sure to update the copies in the different encoders if you change
62 const int avpriv_mpeg4audio_sample_rates[16] = {
63 96000, 88200, 64000, 48000, 44100, 32000,
64 24000, 22050, 16000, 12000, 11025, 8000, 7350
67 const uint8_t ff_mpeg4audio_channels[14] = {
81 24 // 3/3/3 - 5/2/3 - 3/0/0.2
84 static inline int get_object_type(GetBitContext *gb)
86 int object_type = get_bits(gb, 5);
87 if (object_type == AOT_ESCAPE)
88 object_type = 32 + get_bits(gb, 6);
92 static inline int get_sample_rate(GetBitContext *gb, int *index)
94 *index = get_bits(gb, 4);
95 return *index == 0x0f ? get_bits(gb, 24) :
96 avpriv_mpeg4audio_sample_rates[*index];
99 int ff_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb,
100 int sync_extension, void *logctx)
102 int specific_config_bitindex, ret;
103 int start_bit_index = get_bits_count(gb);
104 c->object_type = get_object_type(gb);
105 c->sample_rate = get_sample_rate(gb, &c->sampling_index);
106 c->chan_config = get_bits(gb, 4);
107 if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
108 c->channels = ff_mpeg4audio_channels[c->chan_config];
110 av_log(logctx, AV_LOG_ERROR, "Invalid chan_config %d\n", c->chan_config);
111 return AVERROR_INVALIDDATA;
115 if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
116 // check for W6132 Annex YYYY draft MP3onMP4
117 !(show_bits(gb, 3) & 0x03 && !(show_bits(gb, 9) & 0x3F)))) {
118 if (c->object_type == AOT_PS)
120 c->ext_object_type = AOT_SBR;
122 c->ext_sample_rate = get_sample_rate(gb, &c->ext_sampling_index);
123 c->object_type = get_object_type(gb);
124 if (c->object_type == AOT_ER_BSAC)
125 c->ext_chan_config = get_bits(gb, 4);
127 c->ext_object_type = AOT_NULL;
128 c->ext_sample_rate = 0;
130 specific_config_bitindex = get_bits_count(gb);
132 if (c->object_type == AOT_ALS) {
134 if (show_bits(gb, 24) != MKBETAG('\0','A','L','S'))
137 specific_config_bitindex = get_bits_count(gb);
139 ret = parse_config_ALS(gb, c, logctx);
144 if (c->ext_object_type != AOT_SBR && sync_extension) {
145 while (get_bits_left(gb) > 15) {
146 if (show_bits(gb, 11) == 0x2b7) { // sync extension
148 c->ext_object_type = get_object_type(gb);
149 if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(gb)) == 1) {
150 c->ext_sample_rate = get_sample_rate(gb, &c->ext_sampling_index);
151 if (c->ext_sample_rate == c->sample_rate)
154 if (get_bits_left(gb) > 11 && get_bits(gb, 11) == 0x548)
155 c->ps = get_bits1(gb);
158 get_bits1(gb); // skip 1 bit
165 //Limit implicit PS to the HE-AACv2 Profile
166 if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
169 return specific_config_bitindex - start_bit_index;
172 #if LIBAVCODEC_VERSION_MAJOR < 59
173 int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
174 int bit_size, int sync_extension)
180 return AVERROR_INVALIDDATA;
182 ret = init_get_bits(&gb, buf, bit_size);
186 return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension, NULL);
190 int avpriv_mpeg4audio_get_config2(MPEG4AudioConfig *c, const uint8_t *buf,
191 int size, int sync_extension, void *logctx)
197 return AVERROR_INVALIDDATA;
199 ret = init_get_bits8(&gb, buf, size);
203 return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension, logctx);