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/*****************************************************************************
* a52.h
*****************************************************************************
* Copyright (C) 2001-2016 Laurent Aimar
*
* Authors: Stéphane Borel <stef@via.ecp.fr>
* Christophe Massiot <massiot@via.ecp.fr>
* Gildas Bazin <gbazin@videolan.org>
* Laurent Aimar <fenrir@via.ecp.fr>
* Thomas Guillem <thomas@gllm.fr>
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#ifndef VLC_A52_H_
#define VLC_A52_H_
#include <vlc_bits.h>
/**
* Minimum AC3 header size that vlc_a52_header_Parse needs.
*/
#define VLC_A52_MIN_HEADER_SIZE (8)
#define VLC_A52_EAC3_BSI_SIZE ((532 + 7)/8)
#define VLC_A52_EAC3_HEADER_SIZE (VLC_A52_EAC3_BSI_SIZE + 2)
/**
* AC3 header information.
*/
struct vlc_a52_bitstream_info
{
uint8_t i_fscod;
uint8_t i_frmsizcod;
uint8_t i_bsid;
uint8_t i_bsmod;
uint8_t i_acmod;
uint8_t i_lfeon;
union
{
struct {
enum {
EAC3_STRMTYP_INDEPENDENT = 0,
EAC3_STRMTYP_DEPENDENT = 1,
EAC3_STRMTYP_AC3_CONVERT = 2,
EAC3_STRMTYP_RESERVED,
} strmtyp;
uint16_t i_frmsiz;
uint8_t i_fscod2;
uint8_t i_numblkscod;
uint8_t i_substreamid;
} eac3;
struct
{
uint8_t i_dsurmod;
} ac3;
};
};
typedef struct
{
bool b_eac3;
unsigned int i_channels;
unsigned int i_channels_conf;
unsigned int i_chan_mode;
unsigned int i_rate;
unsigned int i_bitrate;
unsigned int i_size;
unsigned int i_samples;
struct vlc_a52_bitstream_info bs;
uint8_t i_blocks_per_sync_frame;
} vlc_a52_header_t;
/**
* It parse AC3 sync info.
*
* cf. AC3 spec
*/
static inline int vlc_a52_ParseAc3BitstreamInfo( struct vlc_a52_bitstream_info *bs,
const uint8_t *p_buf, size_t i_buf )
{
bs_t s;
bs_init( &s, p_buf, i_buf );
/* cf. 5.3.2 */
bs->i_fscod = bs_read( &s, 2 );
if( bs->i_fscod == 3 )
return VLC_EGENERIC;
bs->i_frmsizcod = bs_read( &s, 6 );
if( bs->i_frmsizcod >= 38 )
return VLC_EGENERIC;
bs->i_bsid = bs_read( &s, 5 );
bs->i_bsmod = bs_read( &s, 3 );
bs->i_acmod = bs_read( &s, 3 );
if( ( bs->i_acmod & 0x1 ) && ( bs->i_acmod != 0x1 ) )
{
/* if 3 front channels */
bs_skip( &s, 2 ); /* i_cmixlev */
}
if( bs->i_acmod & 0x4 )
{
/* if a surround channel exists */
bs_skip( &s, 2 ); /* i_surmixlev */
}
/* if in 2/0 mode */
bs->ac3.i_dsurmod = bs->i_acmod == 0x2 ? bs_read( &s, 2 ) : 0;
bs->i_lfeon = bs_read( &s, 1 );
return VLC_SUCCESS;
}
static inline int vlc_a52_header_ParseAc3( vlc_a52_header_t *p_header,
const uint8_t *p_buf,
const uint32_t *p_acmod,
const unsigned *pi_fscod_samplerates )
{
if( vlc_a52_ParseAc3BitstreamInfo( &p_header->bs,
&p_buf[4], /* start code + CRC */
VLC_A52_MIN_HEADER_SIZE - 4 ) != VLC_SUCCESS )
return VLC_EGENERIC;
/* cf. Table 5.18 Frame Size Code Table */
static const uint16_t ppi_frmsizcod_fscod_sizes[][3] = {
/* 32K, 44.1K, 48K */
{ 96, 69, 64 },
{ 96, 70, 64 },
{ 120, 87, 80 },
{ 120, 88, 80 },
{ 144, 104, 96 },
{ 144, 105, 96 },
{ 168, 121, 112 },
{ 168, 122, 112 },
{ 192, 139, 128 },
{ 192, 140, 128 },
{ 240, 174, 160 },
{ 240, 175, 160 },
{ 288, 208, 192 },
{ 288, 209, 192 },
{ 336, 243, 224 },
{ 336, 244, 224 },
{ 384, 278, 256 },
{ 384, 279, 256 },
{ 480, 348, 320 },
{ 480, 349, 320 },
{ 576, 417, 384 },
{ 576, 418, 384 },
{ 672, 487, 448 },
{ 672, 488, 448 },
{ 768, 557, 512 },
{ 768, 558, 512 },
{ 960, 696, 640 },
{ 960, 697, 640 },
{ 1152, 835, 768 },
{ 1152, 836, 768 },
{ 1344, 975, 896 },
{ 1344, 976, 896 },
{ 1536, 1114, 1024 },
{ 1536, 1115, 1024 },
{ 1728, 1253, 1152 },
{ 1728, 1254, 1152 },
{ 1920, 1393, 1280 },
{ 1920, 1394, 1280 }
};
static const uint16_t pi_frmsizcod_bitrates[] = {
32, 40, 48, 56,
64, 80, 96, 112,
128, 160, 192, 224,
256, 320, 384, 448,
512, 576, 640
};
const struct vlc_a52_bitstream_info *bs = &p_header->bs;
p_header->i_channels_conf = p_acmod[bs->i_acmod];
p_header->i_chan_mode = 0;
if( bs->ac3.i_dsurmod == 2 )
p_header->i_chan_mode |= AOUT_CHANMODE_DOLBYSTEREO;
if( bs->i_acmod == 0 )
p_header->i_chan_mode |= AOUT_CHANMODE_DUALMONO;
if( bs->i_lfeon )
p_header->i_channels_conf |= AOUT_CHAN_LFE;
p_header->i_channels = vlc_popcount(p_header->i_channels_conf);
const unsigned i_rate_shift = VLC_CLIP(bs->i_bsid, 8, 11) - 8;
p_header->i_bitrate = (pi_frmsizcod_bitrates[bs->i_frmsizcod >> 1] * 1000)
>> i_rate_shift;
p_header->i_rate = pi_fscod_samplerates[bs->i_fscod] >> i_rate_shift;
p_header->i_size = ppi_frmsizcod_fscod_sizes[bs->i_frmsizcod]
[2 - bs->i_fscod] * 2;
p_header->i_blocks_per_sync_frame = 6;
p_header->i_samples = p_header->i_blocks_per_sync_frame * 256;
p_header->b_eac3 = false;
return VLC_SUCCESS;
}
/**
* It parse E-AC3 sync info
*/
static inline int vlc_a52_ParseEac3BitstreamInfo( struct vlc_a52_bitstream_info *bs,
const uint8_t *p_buf, size_t i_buf )
{
bs_t s;
bs_init( &s, p_buf, i_buf );
bs->eac3.strmtyp = bs_read( &s, 2 ); /* Stream Type */
bs->eac3.i_substreamid = bs_read( &s, 3 );/* Substream Identification */
bs->eac3.i_frmsiz = bs_read( &s, 11 );
if( bs->eac3.i_frmsiz < 2 )
return VLC_EGENERIC;
bs->i_fscod = bs_read( &s, 2 );
if( bs->i_fscod == 0x03 )
{
bs->eac3.i_fscod2 = bs_read( &s, 2 );
if( bs->eac3.i_fscod2 == 0x03 )
return VLC_EGENERIC;
bs->eac3.i_numblkscod = 0x03;
}
else bs->eac3.i_numblkscod = bs_read( &s, 2 );
bs->i_acmod = bs_read( &s, 3 );
bs->i_lfeon = bs_read1( &s );
bs->i_bsid = bs_read( &s, 5 );
if( i_buf <= VLC_A52_MIN_HEADER_SIZE )
{
bs->i_bsmod = 0;
return VLC_SUCCESS;
}
bs_skip( &s, 5 ); /* dialnorm */
if(bs_read1( &s ))
bs_skip( &s, 8 ); /* compr */
if( bs->i_acmod == 0x00 )
{
bs_skip( &s, 5 );
if(bs_read1( &s ))
bs_skip( &s, 8 ); /* compr2 */
}
if( bs->eac3.strmtyp == 0x01 && bs_read1( &s ) )
bs_skip( &s, 16 ); /* chanmap */
if( bs_read1( &s ) ) /* mixmdate */
{
if( bs->i_acmod > 0x02 )
{
bs_skip( &s, 2 ); /* dmixmod */
if( bs->i_acmod & 0x01 )
bs_skip( &s, 6 ); /* ltrtcmixlev + lorocmixlev */
if( bs->i_acmod & 0x04 )
bs_skip( &s, 6 ); /* ltrtsurmixlev + lorosurmixlev */
}
if( bs->i_lfeon && bs_read1( &s ) )
bs_skip( &s, 5 ); /* (lfemixlevcode) */
if( bs->eac3.strmtyp == 0x00 )
{
if( bs_read1( &s ) )
bs_skip( &s, 6 ); /* pgmscl */
if( bs->i_acmod == 0x00 && bs_read1( &s ) )
bs_skip( &s, 6 ); /* pgmscl2 */
if(bs_read1( &s ))
bs_skip( &s, 6 ); /* extpgmscl */
const uint8_t i_mixdef = bs_read( &s, 2 );
if( i_mixdef == 0x01 )
bs_skip( &s, 5 ); /* premixcmpsel + drcsrc + premixcmpscl */
else if( i_mixdef == 0x02 )
bs_skip( &s, 12 ); /* mixdata */
else if( i_mixdef == 0x03 )
{
const unsigned mixdeflen = bs_read( &s, 5 ) + 2;
for(size_t i=0; i<mixdeflen; i++)
bs_skip( &s, 8 );
bs_align( &s );
}
if( bs->i_acmod < 0x02 )
{
if( bs_read1( &s ) )
bs_skip( &s, 14 ); /* panmean + paninfo */
if( bs->i_acmod == 0x00 && bs_read1( &s ) )
bs_skip( &s, 14 ); /* panmean2 + paninfo2 */
}
if( bs_read1( &s ) )
{
const uint8_t blkspersyncframe[] = { 0+1, 1, 2, 6 };
const size_t nb = blkspersyncframe[bs->eac3.i_numblkscod];
for(size_t i=0; i<nb; i++)
{
if( bs->eac3.i_numblkscod == 0x00 )
bs_skip( &s, 5 ); /* blkmixcfginfo[N] */
}
}
}
}
if( bs_read1( &s ) ) /* infomdate */
{
bs->i_bsmod = bs_read( &s, 3 );
// ...
}
else bs->i_bsmod = 0;
return VLC_SUCCESS;
}
static inline int vlc_a52_header_ParseEac3( vlc_a52_header_t *p_header,
const uint8_t *p_buf,
const uint32_t *p_acmod,
const unsigned *pi_fscod_samplerates )
{
if( vlc_a52_ParseEac3BitstreamInfo( &p_header->bs,
&p_buf[2], /* start code */
VLC_A52_MIN_HEADER_SIZE - 2 ) != VLC_SUCCESS )
return VLC_EGENERIC;
const struct vlc_a52_bitstream_info *bs = &p_header->bs;
p_header->i_size = 2 * (bs->eac3.i_frmsiz + 1 );
if( bs->i_fscod == 0x03 )
{
p_header->i_rate = pi_fscod_samplerates[bs->eac3.i_fscod2] / 2;
p_header->i_blocks_per_sync_frame = 6;
}
else
{
static const int pi_numblkscod [4] = { 1, 2, 3, 6 };
p_header->i_rate = pi_fscod_samplerates[bs->i_fscod];
p_header->i_blocks_per_sync_frame = pi_numblkscod[bs->eac3.i_numblkscod];
}
p_header->i_channels_conf = p_acmod[bs->i_acmod];
p_header->i_chan_mode = 0;
if( bs->i_acmod == 0 )
p_header->i_chan_mode |= AOUT_CHANMODE_DUALMONO;
if( bs->i_lfeon )
p_header->i_channels_conf |= AOUT_CHAN_LFE;
p_header->i_channels = vlc_popcount( p_header->i_channels_conf );
p_header->i_bitrate = 8 * p_header->i_size * p_header->i_rate
/ (p_header->i_blocks_per_sync_frame * 256);
p_header->i_samples = p_header->i_blocks_per_sync_frame * 256;
p_header->b_eac3 = true;
return VLC_SUCCESS;
}
/**
* It will parse the header AC3 frame and fill vlc_a52_header_t* if
* it is valid or return VLC_EGENERIC.
*
* XXX It will only recognize big endian bitstream ie starting with 0x0b, 0x77
*/
static inline int vlc_a52_header_Parse( vlc_a52_header_t *p_header,
const uint8_t *p_buffer, int i_buffer )
{
static const uint32_t p_acmod[8] = {
AOUT_CHANS_2_0,
AOUT_CHAN_CENTER,
AOUT_CHANS_2_0,
AOUT_CHANS_3_0,
AOUT_CHANS_FRONT | AOUT_CHAN_REARCENTER, /* 2F1R */
AOUT_CHANS_FRONT | AOUT_CHANS_CENTER, /* 3F1R */
AOUT_CHANS_4_0,
AOUT_CHANS_5_0,
};
static const unsigned pi_fscod_samplerates[] = {
48000, 44100, 32000
};
if( i_buffer < VLC_A52_MIN_HEADER_SIZE )
return VLC_EGENERIC;
/* Check synword */
if( p_buffer[0] != 0x0b || p_buffer[1] != 0x77 )
return VLC_EGENERIC;
/* Check bsid */
const int bsid = p_buffer[5] >> 3;
/* cf. Annex E 2.3.1.6 of AC3 spec */
if( bsid <= 10 )
return vlc_a52_header_ParseAc3( p_header, p_buffer,
p_acmod, pi_fscod_samplerates );
else if( bsid <= 16 )
return vlc_a52_header_ParseEac3( p_header, p_buffer,
p_acmod, pi_fscod_samplerates );
else
return VLC_EGENERIC;
}
#endif