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https://github.com/FFmpeg/FFmpeg.git
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fd095539d1
Pass the correct size in bits to mpeg4audio_get_config and add a flag to disable parsing of the sync extension when the size is not known. Latm with AudioMuxVersion 0 does not specify the size of the audio specific config. Data after the audio specific config can be misinterpreted as sync extension resulting in random and wrong configs.
185 lines
6.1 KiB
C
185 lines
6.1 KiB
C
/*
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* MPEG-4 Audio common code
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* Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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* Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "get_bits.h"
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#include "put_bits.h"
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#include "mpeg4audio.h"
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/**
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* Parse MPEG-4 audio configuration for ALS object type.
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* @param[in] gb bit reader context
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* @param[in] c MPEG4AudioConfig structure to fill
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* @return on success 0 is returned, otherwise a value < 0
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*/
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static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
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{
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if (get_bits_left(gb) < 112)
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return -1;
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if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
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return -1;
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// override AudioSpecificConfig channel configuration and sample rate
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// which are buggy in old ALS conformance files
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c->sample_rate = get_bits_long(gb, 32);
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// skip number of samples
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skip_bits_long(gb, 32);
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// read number of channels
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c->chan_config = 0;
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c->channels = get_bits(gb, 16) + 1;
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return 0;
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}
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const int avpriv_mpeg4audio_sample_rates[16] = {
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96000, 88200, 64000, 48000, 44100, 32000,
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24000, 22050, 16000, 12000, 11025, 8000, 7350
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};
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const uint8_t ff_mpeg4audio_channels[8] = {
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0, 1, 2, 3, 4, 5, 6, 8
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};
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static inline int get_object_type(GetBitContext *gb)
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{
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int object_type = get_bits(gb, 5);
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if (object_type == AOT_ESCAPE)
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object_type = 32 + get_bits(gb, 6);
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return object_type;
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}
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static inline int get_sample_rate(GetBitContext *gb, int *index)
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{
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*index = get_bits(gb, 4);
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return *index == 0x0f ? get_bits(gb, 24) :
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avpriv_mpeg4audio_sample_rates[*index];
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}
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int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
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int bit_size, int sync_extension)
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{
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GetBitContext gb;
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int specific_config_bitindex;
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init_get_bits(&gb, buf, bit_size);
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c->object_type = get_object_type(&gb);
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c->sample_rate = get_sample_rate(&gb, &c->sampling_index);
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c->chan_config = get_bits(&gb, 4);
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if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
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c->channels = ff_mpeg4audio_channels[c->chan_config];
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c->sbr = -1;
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c->ps = -1;
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if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
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// check for W6132 Annex YYYY draft MP3onMP4
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!(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {
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if (c->object_type == AOT_PS)
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c->ps = 1;
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c->ext_object_type = AOT_SBR;
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c->sbr = 1;
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c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
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c->object_type = get_object_type(&gb);
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if (c->object_type == AOT_ER_BSAC)
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c->ext_chan_config = get_bits(&gb, 4);
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} else {
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c->ext_object_type = AOT_NULL;
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c->ext_sample_rate = 0;
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}
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specific_config_bitindex = get_bits_count(&gb);
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if (c->object_type == AOT_ALS) {
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skip_bits(&gb, 5);
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if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
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skip_bits_long(&gb, 24);
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specific_config_bitindex = get_bits_count(&gb);
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if (parse_config_ALS(&gb, c))
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return -1;
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}
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if (c->ext_object_type != AOT_SBR && sync_extension) {
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while (get_bits_left(&gb) > 15) {
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if (show_bits(&gb, 11) == 0x2b7) { // sync extension
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get_bits(&gb, 11);
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c->ext_object_type = get_object_type(&gb);
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if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1)
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c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
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if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)
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c->ps = get_bits1(&gb);
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break;
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} else
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get_bits1(&gb); // skip 1 bit
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}
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}
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//PS requires SBR
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if (!c->sbr)
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c->ps = 0;
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//Limit implicit PS to the HE-AACv2 Profile
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if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
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c->ps = 0;
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return specific_config_bitindex;
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}
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static av_always_inline unsigned int copy_bits(PutBitContext *pb,
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GetBitContext *gb,
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int bits)
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{
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unsigned int el = get_bits(gb, bits);
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put_bits(pb, bits, el);
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return el;
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}
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int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
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{
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int five_bit_ch, four_bit_ch, comment_size, bits;
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int offset = put_bits_count(pb);
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copy_bits(pb, gb, 10); //Tag, Object Type, Frequency
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five_bit_ch = copy_bits(pb, gb, 4); //Front
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five_bit_ch += copy_bits(pb, gb, 4); //Side
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five_bit_ch += copy_bits(pb, gb, 4); //Back
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four_bit_ch = copy_bits(pb, gb, 2); //LFE
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four_bit_ch += copy_bits(pb, gb, 3); //Data
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five_bit_ch += copy_bits(pb, gb, 4); //Coupling
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if (copy_bits(pb, gb, 1)) //Mono Mixdown
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copy_bits(pb, gb, 4);
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if (copy_bits(pb, gb, 1)) //Stereo Mixdown
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copy_bits(pb, gb, 4);
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if (copy_bits(pb, gb, 1)) //Matrix Mixdown
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copy_bits(pb, gb, 3);
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for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
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copy_bits(pb, gb, 16);
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if (bits)
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copy_bits(pb, gb, bits);
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avpriv_align_put_bits(pb);
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align_get_bits(gb);
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comment_size = copy_bits(pb, gb, 8);
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for (; comment_size > 0; comment_size--)
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copy_bits(pb, gb, 8);
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return put_bits_count(pb) - offset;
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}
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