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packetizer/a52: rewrite header parser 

Rewrite with bit stream helpers using the AC3/EAC3 spec. Add
i_blocks_per_sync_frame, eac3.strmtyp, eac3.i_substreamid that will be used by
the S/PDIF converter.
pull/50/head
Thomas Guillem 10 years ago
parent
48e47d0508
commit
569afcae5b
1 changed files with 138 additions and 83 deletions
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  1. 221
      modules/packetizer/a52.h

221
modules/packetizer/a52.h
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@ -1,13 +1,14 @@
/*****************************************************************************
* a52.h
*****************************************************************************
* Copyright (C) 2001-2009 Laurent Aimar
* Copyright (C) 2001-2016 Laurent Aimar
* $Id$
*
* 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
@ -49,66 +50,125 @@ typedef struct
unsigned int i_size;
unsigned int i_samples;
union {
struct {
enum {
EAC3_STRMTYP_INDEPENDENT = 0,
EAC3_STRMTYP_DEPENDENT = 1,
EAC3_STRMTYP_AC3_CONVERT = 2,
EAC3_STRMTYP_RESERVED,
} strmtyp;
uint8_t i_substreamid;
} eac3;
};
uint8_t i_blocks_per_sync_frame;
} vlc_a52_header_t;
/**
* It parse AC3 sync info.
*
* This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
* since we don't want to oblige S/PDIF people to use liba52 just to get
* their SyncInfo...
* cf. AC3 spec
*/
static inline int vlc_a52_header_ParseAc3( vlc_a52_header_t *p_header,
const uint8_t *p_buf,
const uint32_t *p_acmod )
const uint32_t *p_acmod,
const unsigned *pi_fscod_samplerates )
{
static const uint8_t pi_halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
static const unsigned int pi_bitrate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
128, 160, 192, 224, 256, 320, 384, 448,
512, 576, 640 };
static const uint8_t pi_lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
0x04, 0x01, 0x04, 0x01 };
/* */
const unsigned i_rate_shift = pi_halfrate[p_buf[5] >> 3];
/* acmod, dsurmod and lfeon */
const unsigned i_acmod = p_buf[6] >> 5;
if( (p_buf[6] & 0xf8) == 0x50 )
/* Dolby surround = stereo + Dolby */
p_header->i_channels_conf = AOUT_CHANS_STEREO | AOUT_CHAN_DOLBYSTEREO;
else
p_header->i_channels_conf = p_acmod[i_acmod];
if( p_buf[6] & pi_lfeon[i_acmod] )
p_header->i_channels_conf |= AOUT_CHAN_LFE;
/* 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
};
p_header->i_channels = popcount(p_header->i_channels_conf
& AOUT_CHAN_PHYSMASK);
bs_t s;
bs_init( &s, (void*)p_buf, VLC_A52_HEADER_SIZE );
bs_skip( &s, 32 ); /* start code + CRC */
const unsigned i_frmsizecod = p_buf[4] & 63;
if( i_frmsizecod >= 38 )
/* cf. 5.3.2 */
const uint8_t i_fscod = bs_read( &s, 2 );
if( i_fscod == 3 )
return VLC_EGENERIC;
const unsigned i_bitrate_base = pi_bitrate[i_frmsizecod >> 1];
p_header->i_bitrate = (i_bitrate_base * 1000) >> i_rate_shift;
switch( p_buf[4] & 0xc0 )
{
case 0:
p_header->i_rate = 48000 >> i_rate_shift;
p_header->i_size = 4 * i_bitrate_base;
break;
case 0x40:
p_header->i_rate = 44100 >> i_rate_shift;
p_header->i_size = 2 * (320 * i_bitrate_base / 147 + (i_frmsizecod & 1));
break;
case 0x80:
p_header->i_rate = 32000 >> i_rate_shift;
p_header->i_size = 6 * i_bitrate_base;
break;
default:
const uint8_t i_frmsizcod = bs_read( &s, 6 );
if( i_frmsizcod >= 38 )
return VLC_EGENERIC;
const uint8_t i_bsid = bs_read( &s, 5 );
bs_skip( &s, 3 ); /* i_bsmod */
const uint8_t i_acmod = bs_read( &s, 3 );
if( ( i_acmod & 0x1 ) && ( i_acmod != 0x1 ) )
{
/* if 3 front channels */
bs_skip( &s, 2 ); /* i_cmixlev */
}
if( i_acmod & 0x4 )
{
/* if a surround channel exists */
bs_skip( &s, 2 ); /* i_surmixlev */
}
p_header->i_samples = 6*256;
/* if in 2/0 mode */
const uint8_t i_dsurmod = i_acmod == 0x2 ? bs_read( &s, 2 ) : 0;
const uint8_t i_lfeon = bs_read( &s, 1 );
p_header->i_channels_conf = p_acmod[i_acmod];
if( i_dsurmod == 2 )
p_header->i_channels_conf |= AOUT_CHAN_DOLBYSTEREO;
if( i_lfeon )
p_header->i_channels_conf |= AOUT_CHAN_LFE;
p_header->i_channels = popcount(p_header->i_channels_conf
& AOUT_CHAN_PHYSMASK);
const unsigned i_rate_shift = __MAX(i_bsid, 8) - 8;
p_header->i_bitrate = (pi_frmsizcod_bitrates[i_frmsizcod >> 1] * 1000)
>> i_rate_shift;
p_header->i_rate = pi_fscod_samplerates[i_fscod] >> i_rate_shift;
p_header->i_size = ppi_frmsizcod_fscod_sizes[i_frmsizcod][2 - 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;
@ -119,37 +179,35 @@ static inline int vlc_a52_header_ParseAc3( vlc_a52_header_t *p_header,
*/
static inline int vlc_a52_header_ParseEac3( vlc_a52_header_t *p_header,
const uint8_t *p_buf,
const uint32_t *p_acmod )
const uint32_t *p_acmod,
const unsigned *pi_fscod_samplerates )
{
static const unsigned pi_samplerate[3] = { 48000, 44100, 32000 };
unsigned i_numblkscod;
bs_t s;
bs_init( &s, (void*)p_buf, VLC_A52_HEADER_SIZE );
bs_skip( &s, 16 + /* start code */
2 + /* stream type */
3 ); /* substream id */
const unsigned i_frame_size = bs_read( &s, 11 );
if( i_frame_size < 2 )
bs_skip( &s, 16 ); /* start code */
p_header->eac3.strmtyp = bs_read( &s, 2 ); /* Stream Type */
p_header->eac3.i_substreamid = bs_read( &s, 3 );/* Substream Identification */
const uint16_t i_frmsiz = bs_read( &s, 11 );
if( i_frmsiz < 2 )
return VLC_EGENERIC;
p_header->i_size = 2 * ( i_frame_size + 1 );
p_header->i_size = 2 * (i_frmsiz + 1 );
const unsigned i_fscod = bs_read( &s, 2 );
const uint8_t i_fscod = bs_read( &s, 2 );
if( i_fscod == 0x03 )
{
const unsigned i_fscod2 = bs_read( &s, 2 );
if( i_fscod2 == 0X03 )
const uint8_t i_fscod2 = bs_read( &s, 2 );
if( i_fscod2 == 0x03 )
return VLC_EGENERIC;
p_header->i_rate = pi_samplerate[i_fscod2] / 2;
i_numblkscod = 6;
p_header->i_rate = pi_fscod_samplerates[i_fscod2] / 2;
p_header->i_blocks_per_sync_frame = 6;
}
else
{
static const int pi_blocks[4] = { 1, 2, 3, 6 };
static const int pi_numblkscod [4] = { 1, 2, 3, 6 };
p_header->i_rate = pi_samplerate[i_fscod];
i_numblkscod = pi_blocks[bs_read( &s, 2 )];
p_header->i_rate = pi_fscod_samplerates[i_fscod];
p_header->i_blocks_per_sync_frame = pi_numblkscod[bs_read( &s, 2 )];
}
const unsigned i_acmod = bs_read( &s, 3 );
@ -158,11 +216,11 @@ static inline int vlc_a52_header_ParseEac3( vlc_a52_header_t *p_header,
p_header->i_channels_conf = p_acmod[i_acmod];
if( i_lfeon )
p_header->i_channels_conf |= AOUT_CHAN_LFE;
p_header->i_channels = popcount(p_header->i_channels_conf
& AOUT_CHAN_PHYSMASK);
p_header->i_bitrate = 8 * p_header->i_size * (p_header->i_rate)
/ (i_numblkscod * 256);
p_header->i_samples = i_numblkscod * 256;
p_header->i_channels = popcount( p_header->i_channels_conf
& AOUT_CHAN_PHYSMASK );
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;
@ -187,6 +245,9 @@ static inline int vlc_a52_header_Parse( vlc_a52_header_t *p_header,
AOUT_CHANS_4_0,
AOUT_CHANS_5_0,
};
static const unsigned pi_fscod_samplerates[] = {
48000, 44100, 32000
};
if( i_buffer < VLC_A52_HEADER_SIZE )
return VLC_EGENERIC;
@ -197,20 +258,14 @@ static inline int vlc_a52_header_Parse( vlc_a52_header_t *p_header,
/* Check bsid */
const int bsid = p_buffer[5] >> 3;
if( bsid > 16 )
return VLC_EGENERIC;
if( bsid <= 10 )
{
if( vlc_a52_header_ParseAc3( p_header, p_buffer, p_acmod ) )
return VLC_EGENERIC;
}
/* cf. Annex E 2.3.1.6 of AC3 spec */
if( bsid > 10 && bsid <= 16 )
return vlc_a52_header_ParseEac3( p_header, p_buffer,
p_acmod, pi_fscod_samplerates );
else
{
if( vlc_a52_header_ParseEac3( p_header, p_buffer, p_acmod ) )
return VLC_EGENERIC;
}
return VLC_SUCCESS;
return vlc_a52_header_ParseAc3( p_header, p_buffer,
p_acmod, pi_fscod_samplerates );
}
#endif

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