mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-08-18 07:15:04 +02:00
184 lines
6.0 KiB
C
184 lines
6.0 KiB
C
/*
|
|
* 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);
|
|
|
|
// 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;
|
|
}
|
|
|
|
const int ff_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) :
|
|
ff_mpeg4audio_sample_rates[*index];
|
|
}
|
|
|
|
int ff_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, int buf_size)
|
|
{
|
|
GetBitContext gb;
|
|
int specific_config_bitindex;
|
|
|
|
init_get_bits(&gb, buf, buf_size*8);
|
|
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) {
|
|
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 (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 ff_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);
|
|
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;
|
|
}
|