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/*
* AC - 3 Audio Decoder
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* This code is developed as part of Google Summer of Code 2006 Program .
*
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* Copyright ( c ) 2006 Kartikey Mahendra BHATT ( bhattkm at gmail dot com ) .
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* Copyright ( c ) 2007 Justin Ruggles
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*
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* Portions of this code are derived from liba52
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* http : //liba52.sourceforge.net
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* Copyright ( C ) 2000 - 2003 Michel Lespinasse < walken @ zoy . org >
* Copyright ( C ) 1999 - 2000 Aaron Holtzman < aholtzma @ ess . engr . uvic . ca >
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*
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* This file is part of FFmpeg .
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*
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* FFmpeg is free software ; you can redistribute it and / or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation ; either
* version 2 of the License , or ( at your option ) any later version .
*
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* FFmpeg is distributed in the hope that it will be useful ,
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* but WITHOUT ANY WARRANTY ; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE . See the GNU
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* General Public License for more details .
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*
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* You should have received a copy of the GNU General Public
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* License along with FFmpeg ; if not , write to the Free Software
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* Foundation , Inc . , 51 Franklin Street , Fifth Floor , Boston , MA 02110 - 1301 USA
*/
# include <stdio.h>
# include <stddef.h>
# include <math.h>
# include <string.h>
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# include "avcodec.h"
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# include "ac3_parser.h"
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# include "bitstream.h"
# include "dsputil.h"
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# include "random.h"
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static const int nfchans_tbl [ 8 ] = { 2 , 1 , 2 , 3 , 3 , 4 , 4 , 5 } ;
/* table for exponent to scale_factor mapping
* scale_factor [ i ] = 2 ^ - ( i + 15 )
*/
static float scale_factors [ 25 ] ;
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/** table for grouping exponents */
static uint8_t exp_ungroup_tbl [ 128 ] [ 3 ] ;
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static int16_t l3_quantizers_1 [ 32 ] ;
static int16_t l3_quantizers_2 [ 32 ] ;
static int16_t l3_quantizers_3 [ 32 ] ;
static int16_t l5_quantizers_1 [ 128 ] ;
static int16_t l5_quantizers_2 [ 128 ] ;
static int16_t l5_quantizers_3 [ 128 ] ;
static int16_t l7_quantizers [ 7 ] ;
static int16_t l11_quantizers_1 [ 128 ] ;
static int16_t l11_quantizers_2 [ 128 ] ;
static int16_t l15_quantizers [ 15 ] ;
static const uint8_t qntztab [ 16 ] = { 0 , 5 , 7 , 3 , 7 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 14 , 16 } ;
/* Adjustmens in dB gain */
# define LEVEL_MINUS_3DB 0.7071067811865476
# define LEVEL_MINUS_4POINT5DB 0.5946035575013605
# define LEVEL_MINUS_6DB 0.5000000000000000
# define LEVEL_PLUS_3DB 1.4142135623730951
# define LEVEL_PLUS_6DB 2.0000000000000000
# define LEVEL_ZERO 0.0000000000000000
static const float clevs [ 4 ] = { LEVEL_MINUS_3DB , LEVEL_MINUS_4POINT5DB ,
LEVEL_MINUS_6DB , LEVEL_MINUS_4POINT5DB } ;
static const float slevs [ 4 ] = { LEVEL_MINUS_3DB , LEVEL_MINUS_6DB , LEVEL_ZERO , LEVEL_MINUS_6DB } ;
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# define BLOCK_SIZE 256
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/* Output and input configurations. */
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# define AC3_OUTPUT_UNMODIFIED 0x01
# define AC3_OUTPUT_MONO 0x02
# define AC3_OUTPUT_STEREO 0x04
# define AC3_OUTPUT_DOLBY 0x08
# define AC3_OUTPUT_LFEON 0x10
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typedef struct {
uint8_t acmod ;
uint8_t cmixlev ;
uint8_t surmixlev ;
uint8_t dsurmod ;
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uint8_t blksw [ AC3_MAX_CHANNELS ] ;
uint8_t dithflag [ AC3_MAX_CHANNELS ] ;
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uint8_t cplinu ;
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uint8_t chincpl [ AC3_MAX_CHANNELS ] ;
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uint8_t phsflginu ;
uint8_t cplbegf ;
uint8_t cplendf ;
uint8_t cplcoe ;
uint32_t cplbndstrc ;
uint8_t rematstr ;
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uint8_t rematflg [ AC3_MAX_CHANNELS ] ;
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uint8_t cplexpstr ;
uint8_t lfeexpstr ;
uint8_t chexpstr [ 5 ] ;
uint8_t sdcycod ;
uint8_t fdcycod ;
uint8_t sgaincod ;
uint8_t dbpbcod ;
uint8_t floorcod ;
uint8_t csnroffst ;
uint8_t cplfsnroffst ;
uint8_t cplfgaincod ;
uint8_t fsnroffst [ 5 ] ;
uint8_t fgaincod [ 5 ] ;
uint8_t lfefsnroffst ;
uint8_t lfefgaincod ;
uint8_t cplfleak ;
uint8_t cplsleak ;
uint8_t cpldeltbae ;
uint8_t deltbae [ 5 ] ;
uint8_t cpldeltnseg ;
uint8_t cpldeltoffst [ 8 ] ;
uint8_t cpldeltlen [ 8 ] ;
uint8_t cpldeltba [ 8 ] ;
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int deltnseg [ 5 ] ;
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uint8_t deltoffst [ 5 ] [ 8 ] ;
uint8_t deltlen [ 5 ] [ 8 ] ;
uint8_t deltba [ 5 ] [ 8 ] ;
/* Derived Attributes. */
int sampling_rate ;
int bit_rate ;
int frame_size ;
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int nchans ; //number of total channels
int nfchans ; //number of full-bandwidth channels
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int lfeon ; //lfe channel in use
float dynrng ; //dynamic range gain
float dynrng2 ; //dynamic range gain for 1+1 mode
float chcoeffs [ 6 ] ; //normalized channel coefficients
float cplco [ 5 ] [ 18 ] ; //coupling coordinates
int ncplbnd ; //number of coupling bands
int ncplsubnd ; //number of coupling sub bands
int cplstrtmant ; //coupling start mantissa
int cplendmant ; //coupling end mantissa
int endmant [ 5 ] ; //channel end mantissas
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AC3BitAllocParameters bit_alloc_params ; ///< bit allocation parameters
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int8_t dcplexps [ 256 ] ; //decoded coupling exponents
int8_t dexps [ 5 ] [ 256 ] ; //decoded fbw channel exponents
int8_t dlfeexps [ 256 ] ; //decoded lfe channel exponents
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uint8_t cplbap [ 256 ] ; //coupling bit allocation pointers
uint8_t bap [ 5 ] [ 256 ] ; //fbw channel bit allocation pointers
uint8_t lfebap [ 256 ] ; //lfe channel bit allocation pointers
int blkoutput ; //output configuration for block
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DECLARE_ALIGNED_16 ( float , transform_coeffs [ AC3_MAX_CHANNELS ] [ BLOCK_SIZE ] ) ; //transform coefficients
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/* For IMDCT. */
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MDCTContext imdct_512 ; //for 512 sample imdct transform
MDCTContext imdct_256 ; //for 256 sample imdct transform
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DSPContext dsp ; //for optimization
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DECLARE_ALIGNED_16 ( float , output [ AC3_MAX_CHANNELS ] [ BLOCK_SIZE ] ) ; //output after imdct transform and windowing
DECLARE_ALIGNED_16 ( float , delay [ AC3_MAX_CHANNELS ] [ BLOCK_SIZE ] ) ; //delay - added to the next block
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DECLARE_ALIGNED_16 ( float , tmp_imdct [ BLOCK_SIZE ] ) ; //temporary storage for imdct transform
DECLARE_ALIGNED_16 ( float , tmp_output [ BLOCK_SIZE * 2 ] ) ; //temporary storage for output before windowing
DECLARE_ALIGNED_16 ( float , window [ BLOCK_SIZE ] ) ; //window coefficients
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/* Miscellaneous. */
GetBitContext gb ;
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AVRandomState dith_state ; //for dither generation
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} AC3DecodeContext ;
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/*********** BEGIN INIT HELPER FUNCTIONS ***********/
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/**
* Generate a Kaiser - Bessel Derived Window .
*/
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static void ac3_window_init ( float * window )
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{
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int i , j ;
double sum = 0.0 , bessel , tmp ;
double local_window [ 256 ] ;
double alpha2 = ( 5.0 * M_PI / 256.0 ) * ( 5.0 * M_PI / 256.0 ) ;
for ( i = 0 ; i < 256 ; i + + ) {
tmp = i * ( 256 - i ) * alpha2 ;
bessel = 1.0 ;
for ( j = 100 ; j > 0 ; j - - ) /* defaul to 100 iterations */
bessel = bessel * tmp / ( j * j ) + 1 ;
sum + = bessel ;
local_window [ i ] = sum ;
}
sum + + ;
for ( i = 0 ; i < 256 ; i + + )
window [ i ] = sqrt ( local_window [ i ] / sum ) ;
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}
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/*
* Generate quantizer tables .
*/
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static void generate_quantizers_table ( int16_t quantizers [ ] , int level , int length )
{
int i ;
for ( i = 0 ; i < length ; i + + )
quantizers [ i ] = ( ( 2 * i - level + 1 ) < < 15 ) / level ;
}
static void generate_quantizers_table_1 ( int16_t quantizers [ ] , int level , int length1 , int length2 , int size )
{
int i , j ;
int16_t v ;
for ( i = 0 ; i < length1 ; i + + ) {
v = ( ( 2 * i - level + 1 ) < < 15 ) / level ;
for ( j = 0 ; j < length2 ; j + + )
quantizers [ i * length2 + j ] = v ;
}
for ( i = length1 * length2 ; i < size ; i + + )
quantizers [ i ] = 0 ;
}
static void generate_quantizers_table_2 ( int16_t quantizers [ ] , int level , int length1 , int length2 , int size )
{
int i , j ;
int16_t v ;
for ( i = 0 ; i < length1 ; i + + ) {
v = ( ( 2 * ( i % level ) - level + 1 ) < < 15 ) / level ;
for ( j = 0 ; j < length2 ; j + + )
quantizers [ i * length2 + j ] = v ;
}
for ( i = length1 * length2 ; i < size ; i + + )
quantizers [ i ] = 0 ;
}
static void generate_quantizers_table_3 ( int16_t quantizers [ ] , int level , int length1 , int length2 , int size )
{
int i , j ;
for ( i = 0 ; i < length1 ; i + + )
for ( j = 0 ; j < length2 ; j + + )
quantizers [ i * length2 + j ] = ( ( 2 * ( j % level ) - level + 1 ) < < 15 ) / level ;
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for ( i = length1 * length2 ; i < size ; i + + )
quantizers [ i ] = 0 ;
}
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/*
* Initialize tables at runtime .
*/
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static void ac3_tables_init ( void )
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{
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int i ;
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/* Quantizer ungrouping tables. */
// for level-3 quantizers
generate_quantizers_table_1 ( l3_quantizers_1 , 3 , 3 , 9 , 32 ) ;
generate_quantizers_table_2 ( l3_quantizers_2 , 3 , 9 , 3 , 32 ) ;
generate_quantizers_table_3 ( l3_quantizers_3 , 3 , 9 , 3 , 32 ) ;
//for level-5 quantizers
generate_quantizers_table_1 ( l5_quantizers_1 , 5 , 5 , 25 , 128 ) ;
generate_quantizers_table_2 ( l5_quantizers_2 , 5 , 25 , 5 , 128 ) ;
generate_quantizers_table_3 ( l5_quantizers_3 , 5 , 25 , 5 , 128 ) ;
//for level-7 quantizers
generate_quantizers_table ( l7_quantizers , 7 , 7 ) ;
//for level-4 quantizers
generate_quantizers_table_2 ( l11_quantizers_1 , 11 , 11 , 11 , 128 ) ;
generate_quantizers_table_3 ( l11_quantizers_2 , 11 , 11 , 11 , 128 ) ;
//for level-15 quantizers
generate_quantizers_table ( l15_quantizers , 15 , 15 ) ;
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/* End Quantizer ungrouping tables. */
//generate scale factors
for ( i = 0 ; i < 25 ; i + + )
scale_factors [ i ] = pow ( 2.0 , - ( i + 15 ) ) ;
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/* generate exponent tables
reference : Section 7.1 .3 Exponent Decoding */
for ( i = 0 ; i < 128 ; i + + ) {
exp_ungroup_tbl [ i ] [ 0 ] = i / 25 ;
exp_ungroup_tbl [ i ] [ 1 ] = ( i % 25 ) / 5 ;
exp_ungroup_tbl [ i ] [ 2 ] = ( i % 25 ) % 5 ;
}
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}
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static int ac3_decode_init ( AVCodecContext * avctx )
{
AC3DecodeContext * ctx = avctx - > priv_data ;
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ac3_common_init ( ) ;
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ac3_tables_init ( ) ;
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ff_mdct_init ( & ctx - > imdct_256 , 8 , 1 ) ;
ff_mdct_init ( & ctx - > imdct_512 , 9 , 1 ) ;
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ac3_window_init ( ctx - > window ) ;
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dsputil_init ( & ctx - > dsp , avctx ) ;
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av_init_random ( 0 , & ctx - > dith_state ) ;
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return 0 ;
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}
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/*********** END INIT FUNCTIONS ***********/
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/**
* Parses the ' sync info ' and ' bit stream info ' from the AC - 3 bitstream .
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* GetBitContext within AC3DecodeContext must point to
* start of the synchronized ac3 bitstream .
*/
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static int ac3_parse_header ( AC3DecodeContext * ctx )
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{
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AC3HeaderInfo hdr ;
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GetBitContext * gb = & ctx - > gb ;
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int err , i ;
err = ff_ac3_parse_header ( gb - > buffer , & hdr ) ;
if ( err )
return err ;
/* get decoding parameters from header info */
ctx - > bit_alloc_params . fscod = hdr . fscod ;
ctx - > acmod = hdr . acmod ;
ctx - > cmixlev = hdr . cmixlev ;
ctx - > surmixlev = hdr . surmixlev ;
ctx - > dsurmod = hdr . dsurmod ;
ctx - > lfeon = hdr . lfeon ;
ctx - > bit_alloc_params . halfratecod = hdr . halfratecod ;
ctx - > sampling_rate = hdr . sample_rate ;
ctx - > bit_rate = hdr . bit_rate ;
ctx - > nchans = hdr . channels ;
ctx - > nfchans = ctx - > nchans - ctx - > lfeon ;
ctx - > frame_size = hdr . frame_size ;
ctx - > blkoutput = nfchans_tbl [ ctx - > acmod ] ;
if ( ctx - > lfeon )
ctx - > blkoutput | = AC3_OUTPUT_LFEON ;
/* skip over portion of header which has already been read */
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skip_bits ( gb , 16 ) ; //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
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skip_bits ( gb , 16 ) ; // skip crc1
skip_bits ( gb , 8 ) ; // skip fscod and frmsizecod
skip_bits ( gb , 11 ) ; // skip bsid, bsmod, and acmod
if ( ctx - > acmod = = AC3_ACMOD_STEREO ) {
skip_bits ( gb , 2 ) ; // skip dsurmod
} else {
if ( ( ctx - > acmod & 1 ) & & ctx - > acmod ! = AC3_ACMOD_MONO )
skip_bits ( gb , 2 ) ; // skip cmixlev
if ( ctx - > acmod & 4 )
skip_bits ( gb , 2 ) ; // skip surmixlev
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}
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skip_bits1 ( gb ) ; // skip lfeon
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/* read the rest of the bsi. read twice for dual mono mode. */
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i = ! ( ctx - > acmod ) ;
do {
skip_bits ( gb , 5 ) ; //skip dialog normalization
if ( get_bits1 ( gb ) )
skip_bits ( gb , 8 ) ; //skip compression
if ( get_bits1 ( gb ) )
skip_bits ( gb , 8 ) ; //skip language code
if ( get_bits1 ( gb ) )
skip_bits ( gb , 7 ) ; //skip audio production information
} while ( i - - ) ;
skip_bits ( gb , 2 ) ; //skip copyright bit and original bitstream bit
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/* FIXME: read & use the xbsi1 downmix levels */
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if ( get_bits1 ( gb ) )
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skip_bits ( gb , 14 ) ; //skip timecode1
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if ( get_bits1 ( gb ) )
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skip_bits ( gb , 14 ) ; //skip timecode2
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if ( get_bits1 ( gb ) ) {
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i = get_bits ( gb , 6 ) ; //additional bsi length
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do {
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skip_bits ( gb , 8 ) ;
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} while ( i - - ) ;
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}
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return 0 ;
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}
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/**
* Decodes the grouped exponents .
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* This function decodes the coded exponents according to exponent strategy
* and stores them in the decoded exponents buffer .
*
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* @ param [ in ] gb GetBitContext which points to start of coded exponents
* @ param [ in ] expstr Exponent coding strategy
* @ param [ in ] ngrps Number of grouped exponents
* @ param [ in ] absexp Absolute exponent or DC exponent
* @ param [ out ] dexps Decoded exponents are stored in dexps
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*/
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static void decode_exponents ( GetBitContext * gb , int expstr , int ngrps ,
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uint8_t absexp , int8_t * dexps )
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{
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int i , j , grp , grpsize ;
int dexp [ 256 ] ;
int expacc , prevexp ;
/* unpack groups */
grpsize = expstr + ( expstr = = EXP_D45 ) ;
for ( grp = 0 , i = 0 ; grp < ngrps ; grp + + ) {
expacc = get_bits ( gb , 7 ) ;
dexp [ i + + ] = exp_ungroup_tbl [ expacc ] [ 0 ] ;
dexp [ i + + ] = exp_ungroup_tbl [ expacc ] [ 1 ] ;
dexp [ i + + ] = exp_ungroup_tbl [ expacc ] [ 2 ] ;
}
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/* convert to absolute exps and expand groups */
prevexp = absexp ;
for ( i = 0 ; i < ngrps * 3 ; i + + ) {
prevexp = av_clip ( prevexp + dexp [ i ] - 2 , 0 , 24 ) ;
for ( j = 0 ; j < grpsize ; j + + ) {
dexps [ ( i * grpsize ) + j ] = prevexp ;
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}
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}
}
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/* Performs bit allocation.
* This function performs bit allocation for the requested chanenl .
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*/
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static void do_bit_allocation ( AC3DecodeContext * ctx , int chnl )
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{
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int fgain , snroffset ;
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if ( chnl = = 5 ) {
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fgain = ff_fgaintab [ ctx - > cplfgaincod ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > cplfsnroffst ) < < 2 ;
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ac3_parametric_bit_allocation ( & ctx - > bit_alloc_params , ctx - > cplbap ,
ctx - > dcplexps , ctx - > cplstrtmant ,
ctx - > cplendmant , snroffset , fgain , 0 ,
ctx - > cpldeltbae , ctx - > cpldeltnseg ,
ctx - > cpldeltoffst , ctx - > cpldeltlen ,
ctx - > cpldeltba ) ;
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}
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else if ( chnl = = 6 ) {
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fgain = ff_fgaintab [ ctx - > lfefgaincod ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > lfefsnroffst ) < < 2 ;
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ac3_parametric_bit_allocation ( & ctx - > bit_alloc_params , ctx - > lfebap ,
ctx - > dlfeexps , 0 , 7 , snroffset , fgain , 1 ,
DBA_NONE , 0 , NULL , NULL , NULL ) ;
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}
else {
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fgain = ff_fgaintab [ ctx - > fgaincod [ chnl ] ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > fsnroffst [ chnl ] ) < < 2 ;
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ac3_parametric_bit_allocation ( & ctx - > bit_alloc_params , ctx - > bap [ chnl ] ,
ctx - > dexps [ chnl ] , 0 , ctx - > endmant [ chnl ] ,
snroffset , fgain , 0 , ctx - > deltbae [ chnl ] ,
ctx - > deltnseg [ chnl ] , ctx - > deltoffst [ chnl ] ,
ctx - > deltlen [ chnl ] , ctx - > deltba [ chnl ] ) ;
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}
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}
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typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
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int16_t l3_quantizers [ 3 ] ;
int16_t l5_quantizers [ 3 ] ;
int16_t l11_quantizers [ 2 ] ;
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int l3ptr ;
int l5ptr ;
int l11ptr ;
} mant_groups ;
/* Get the transform coefficients for coupling channel and uncouple channels.
* The coupling transform coefficients starts at the the cplstrtmant , which is
* equal to endmant [ ch ] for fbw channels . Hence we can uncouple channels before
* getting transform coefficients for the channel .
*/
static int get_transform_coeffs_cpling ( AC3DecodeContext * ctx , mant_groups * m )
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{
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GetBitContext * gb = & ctx - > gb ;
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int ch , start , end , cplbndstrc , bnd , gcode , tbap ;
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float cplcos [ 5 ] , cplcoeff ;
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uint8_t * exps = ctx - > dcplexps ;
uint8_t * bap = ctx - > cplbap ;
cplbndstrc = ctx - > cplbndstrc ;
start = ctx - > cplstrtmant ;
bnd = 0 ;
while ( start < ctx - > cplendmant ) {
end = start + 12 ;
while ( cplbndstrc & 1 ) {
end + = 12 ;
cplbndstrc > > = 1 ;
}
cplbndstrc > > = 1 ;
for ( ch = 0 ; ch < ctx - > nfchans ; ch + + )
cplcos [ ch ] = ctx - > chcoeffs [ ch ] * ctx - > cplco [ ch ] [ bnd ] ;
bnd + + ;
while ( start < end ) {
tbap = bap [ start ] ;
switch ( tbap ) {
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case 0 :
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for ( ch = 0 ; ch < ctx - > nfchans ; ch + + )
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if ( ctx - > chincpl [ ch ] ) {
if ( ctx - > dithflag [ ch ] ) {
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cplcoeff = ( av_random ( & ctx - > dith_state ) & 0xFFFF ) * scale_factors [ exps [ start ] ] ;
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ctx - > transform_coeffs [ ch + 1 ] [ start ] = cplcoeff * cplcos [ ch ] * LEVEL_MINUS_3DB ;
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} else
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ctx - > transform_coeffs [ ch + 1 ] [ start ] = 0 ;
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}
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start + + ;
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continue ;
case 1 :
if ( m - > l3ptr > 2 ) {
gcode = get_bits ( gb , 5 ) ;
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m - > l3_quantizers [ 0 ] = l3_quantizers_1 [ gcode ] ;
m - > l3_quantizers [ 1 ] = l3_quantizers_2 [ gcode ] ;
m - > l3_quantizers [ 2 ] = l3_quantizers_3 [ gcode ] ;
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m - > l3ptr = 0 ;
}
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cplcoeff = m - > l3_quantizers [ m - > l3ptr + + ] * scale_factors [ exps [ start ] ] ;
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break ;
case 2 :
if ( m - > l5ptr > 2 ) {
gcode = get_bits ( gb , 7 ) ;
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m - > l5_quantizers [ 0 ] = l5_quantizers_1 [ gcode ] ;
m - > l5_quantizers [ 1 ] = l5_quantizers_2 [ gcode ] ;
m - > l5_quantizers [ 2 ] = l5_quantizers_3 [ gcode ] ;
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m - > l5ptr = 0 ;
}
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cplcoeff = m - > l5_quantizers [ m - > l5ptr + + ] * scale_factors [ exps [ start ] ] ;
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break ;
case 3 :
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cplcoeff = l7_quantizers [ get_bits ( gb , 3 ) ] * scale_factors [ exps [ start ] ] ;
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break ;
case 4 :
if ( m - > l11ptr > 1 ) {
gcode = get_bits ( gb , 7 ) ;
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m - > l11_quantizers [ 0 ] = l11_quantizers_1 [ gcode ] ;
m - > l11_quantizers [ 1 ] = l11_quantizers_2 [ gcode ] ;
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m - > l11ptr = 0 ;
}
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cplcoeff = m - > l11_quantizers [ m - > l11ptr + + ] * scale_factors [ exps [ start ] ] ;
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break ;
case 5 :
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cplcoeff = l15_quantizers [ get_bits ( gb , 4 ) ] * scale_factors [ exps [ start ] ] ;
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break ;
default :
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cplcoeff = ( get_sbits ( gb , qntztab [ tbap ] ) < < ( 16 - qntztab [ tbap ] ) ) * scale_factors [ exps [ start ] ] ;
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}
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for ( ch = 0 ; ch < ctx - > nfchans ; ch + + )
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if ( ctx - > chincpl [ ch ] )
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ctx - > transform_coeffs [ ch + 1 ] [ start ] = cplcoeff * cplcos [ ch ] ;
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start + + ;
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}
}
return 0 ;
}
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/* Get the transform coefficients for particular channel */
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static int get_transform_coeffs_ch ( AC3DecodeContext * ctx , int ch_index , mant_groups * m )
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{
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GetBitContext * gb = & ctx - > gb ;
int i , gcode , tbap , dithflag , end ;
uint8_t * exps ;
uint8_t * bap ;
float * coeffs ;
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float factors [ 25 ] ;
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for ( i = 0 ; i < 25 ; i + + )
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factors [ i ] = scale_factors [ i ] * ctx - > chcoeffs [ ch_index ] ;
if ( ch_index ! = - 1 ) { /* fbw channels */
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dithflag = ctx - > dithflag [ ch_index ] ;
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exps = ctx - > dexps [ ch_index ] ;
bap = ctx - > bap [ ch_index ] ;
coeffs = ctx - > transform_coeffs [ ch_index + 1 ] ;
end = ctx - > endmant [ ch_index ] ;
} else if ( ch_index = = - 1 ) {
dithflag = 0 ;
exps = ctx - > dlfeexps ;
bap = ctx - > lfebap ;
coeffs = ctx - > transform_coeffs [ 0 ] ;
end = 7 ;
}
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for ( i = 0 ; i < end ; i + + ) {
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tbap = bap [ i ] ;
switch ( tbap ) {
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case 0 :
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if ( ! dithflag ) {
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coeffs [ i ] = 0 ;
continue ;
}
else {
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coeffs [ i ] = ( av_random ( & ctx - > dith_state ) & 0xFFFF ) * factors [ exps [ i ] ] ;
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coeffs [ i ] * = LEVEL_MINUS_3DB ;
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continue ;
}
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case 1 :
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if ( m - > l3ptr > 2 ) {
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gcode = get_bits ( gb , 5 ) ;
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m - > l3_quantizers [ 0 ] = l3_quantizers_1 [ gcode ] ;
m - > l3_quantizers [ 1 ] = l3_quantizers_2 [ gcode ] ;
m - > l3_quantizers [ 2 ] = l3_quantizers_3 [ gcode ] ;
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m - > l3ptr = 0 ;
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}
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coeffs [ i ] = m - > l3_quantizers [ m - > l3ptr + + ] * factors [ exps [ i ] ] ;
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continue ;
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case 2 :
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if ( m - > l5ptr > 2 ) {
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gcode = get_bits ( gb , 7 ) ;
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m - > l5_quantizers [ 0 ] = l5_quantizers_1 [ gcode ] ;
m - > l5_quantizers [ 1 ] = l5_quantizers_2 [ gcode ] ;
m - > l5_quantizers [ 2 ] = l5_quantizers_3 [ gcode ] ;
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m - > l5ptr = 0 ;
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}
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coeffs [ i ] = m - > l5_quantizers [ m - > l5ptr + + ] * factors [ exps [ i ] ] ;
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continue ;
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case 3 :
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coeffs [ i ] = l7_quantizers [ get_bits ( gb , 3 ) ] * factors [ exps [ i ] ] ;
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continue ;
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case 4 :
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if ( m - > l11ptr > 1 ) {
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gcode = get_bits ( gb , 7 ) ;
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m - > l11_quantizers [ 0 ] = l11_quantizers_1 [ gcode ] ;
m - > l11_quantizers [ 1 ] = l11_quantizers_2 [ gcode ] ;
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m - > l11ptr = 0 ;
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}
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coeffs [ i ] = m - > l11_quantizers [ m - > l11ptr + + ] * factors [ exps [ i ] ] ;
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continue ;
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case 5 :
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coeffs [ i ] = l15_quantizers [ get_bits ( gb , 4 ) ] * factors [ exps [ i ] ] ;
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continue ;
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default :
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coeffs [ i ] = ( get_sbits ( gb , qntztab [ tbap ] ) < < ( 16 - qntztab [ tbap ] ) ) * factors [ exps [ i ] ] ;
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continue ;
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}
}
return 0 ;
}
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/* Get the transform coefficients.
* This function extracts the tranform coefficients form the ac3 bitstream .
* This function is called after bit allocation is performed .
*/
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static int get_transform_coeffs ( AC3DecodeContext * ctx )
{
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int i , end ;
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int got_cplchan = 0 ;
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mant_groups m ;
m . l3ptr = m . l5ptr = m . l11ptr = 3 ;
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for ( i = 0 ; i < ctx - > nfchans ; i + + ) {
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/* transform coefficients for individual channel */
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if ( get_transform_coeffs_ch ( ctx , i , & m ) )
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return - 1 ;
/* tranform coefficients for coupling channels */
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if ( ctx - > chincpl [ i ] ) {
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if ( ! got_cplchan ) {
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if ( get_transform_coeffs_cpling ( ctx , & m ) ) {
av_log ( NULL , AV_LOG_ERROR , " error in decoupling channels \n " ) ;
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return - 1 ;
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}
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got_cplchan = 1 ;
}
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end = ctx - > cplendmant ;
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} else
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end = ctx - > endmant [ i ] ;
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do
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ctx - > transform_coeffs [ i + 1 ] [ end ] = 0 ;
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while ( + + end < 256 ) ;
}
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if ( ctx - > lfeon ) {
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if ( get_transform_coeffs_ch ( ctx , - 1 , & m ) )
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return - 1 ;
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for ( i = 7 ; i < 256 ; i + + ) {
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ctx - > transform_coeffs [ 0 ] [ i ] = 0 ;
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}
}
return 0 ;
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}
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/* Rematrixing routines. */
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static void do_rematrixing1 ( AC3DecodeContext * ctx , int start , int end )
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{
float tmp0 , tmp1 ;
while ( start < end ) {
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tmp0 = ctx - > transform_coeffs [ 1 ] [ start ] ;
tmp1 = ctx - > transform_coeffs [ 2 ] [ start ] ;
ctx - > transform_coeffs [ 1 ] [ start ] = tmp0 + tmp1 ;
ctx - > transform_coeffs [ 2 ] [ start ] = tmp0 - tmp1 ;
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start + + ;
}
}
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static void do_rematrixing ( AC3DecodeContext * ctx )
{
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int bnd1 = 13 , bnd2 = 25 , bnd3 = 37 , bnd4 = 61 ;
int end , bndend ;
end = FFMIN ( ctx - > endmant [ 0 ] , ctx - > endmant [ 1 ] ) ;
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if ( ctx - > rematflg [ 0 ] )
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do_rematrixing1 ( ctx , bnd1 , bnd2 ) ;
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if ( ctx - > rematflg [ 1 ] )
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do_rematrixing1 ( ctx , bnd2 , bnd3 ) ;
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bndend = bnd4 ;
if ( bndend > end ) {
bndend = end ;
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if ( ctx - > rematflg [ 2 ] )
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do_rematrixing1 ( ctx , bnd3 , bndend ) ;
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} else {
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if ( ctx - > rematflg [ 2 ] )
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do_rematrixing1 ( ctx , bnd3 , bnd4 ) ;
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if ( ctx - > rematflg [ 3 ] )
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do_rematrixing1 ( ctx , bnd4 , end ) ;
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}
}
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/* This function sets the normalized channel coefficients.
* Transform coefficients are multipllied by the channel
* coefficients to get normalized transform coefficients .
*/
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static void get_downmix_coeffs ( AC3DecodeContext * ctx )
{
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int from = ctx - > acmod ;
int to = ctx - > blkoutput ;
float clev = clevs [ ctx - > cmixlev ] ;
float slev = slevs [ ctx - > surmixlev ] ;
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float nf = 1.0 ; //normalization factor for downmix coeffs
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int i ;
if ( ! ctx - > acmod ) {
ctx - > chcoeffs [ 0 ] = 2 * ctx - > dynrng ;
ctx - > chcoeffs [ 1 ] = 2 * ctx - > dynrng2 ;
} else {
for ( i = 0 ; i < ctx - > nfchans ; i + + )
ctx - > chcoeffs [ i ] = 2 * ctx - > dynrng ;
}
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if ( to = = AC3_OUTPUT_UNMODIFIED )
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return ;
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switch ( from ) {
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case AC3_ACMOD_DUALMONO :
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switch ( to ) {
case AC3_OUTPUT_MONO :
case AC3_OUTPUT_STEREO : /* We Assume that sum of both mono channels is requested */
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nf = 0.5 ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
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break ;
}
break ;
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case AC3_ACMOD_MONO :
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switch ( to ) {
case AC3_OUTPUT_STEREO :
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nf = LEVEL_MINUS_3DB ;
ctx - > chcoeffs [ 0 ] * = nf ;
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break ;
}
break ;
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case AC3_ACMOD_STEREO :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = LEVEL_MINUS_3DB ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
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break ;
}
break ;
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case AC3_ACMOD_3F :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = LEVEL_MINUS_3DB / ( 1.0 + clev ) ;
ctx - > chcoeffs [ 0 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 2 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 1 ] * = ( ( nf * clev * LEVEL_MINUS_3DB ) / 2.0 ) ;
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break ;
case AC3_OUTPUT_STEREO :
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nf = 1.0 / ( 1.0 + clev ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = ( nf * clev ) ;
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break ;
}
break ;
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case AC3_ACMOD_2F1R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = 2.0 * LEVEL_MINUS_3DB / ( 2.0 + slev ) ;
ctx - > chcoeffs [ 0 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 1 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 2 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_STEREO :
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nf = 1.0 / ( 1.0 + ( slev * LEVEL_MINUS_3DB ) ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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nf = 1.0 / ( 1.0 + LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = ( nf * LEVEL_MINUS_3DB ) ;
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break ;
}
break ;
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case AC3_ACMOD_3F1R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = LEVEL_MINUS_3DB / ( 1.0 + clev + ( slev / 2.0 ) ) ;
ctx - > chcoeffs [ 0 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 2 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 1 ] * = ( nf * clev * LEVEL_PLUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_STEREO :
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nf = 1.0 / ( 1.0 + clev + ( slev * LEVEL_MINUS_3DB ) ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = ( nf * clev ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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nf = 1.0 / ( 1.0 + ( 2.0 * LEVEL_MINUS_3DB ) ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * LEVEL_MINUS_3DB ) ;
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break ;
}
break ;
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case AC3_ACMOD_2F2R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = LEVEL_MINUS_3DB / ( 1.0 + slev ) ;
ctx - > chcoeffs [ 0 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 1 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 2 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_STEREO :
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nf = 1.0 / ( 1.0 + slev ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = ( nf * slev ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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nf = 1.0 / ( 1.0 + ( 2.0 * LEVEL_MINUS_3DB ) ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * LEVEL_MINUS_3DB ) ;
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break ;
}
break ;
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case AC3_ACMOD_3F2R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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nf = LEVEL_MINUS_3DB / ( 1.0 + clev + slev ) ;
ctx - > chcoeffs [ 0 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 2 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 1 ] * = ( nf * clev * LEVEL_PLUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 4 ] * = ( nf * slev * LEVEL_MINUS_3DB ) ;
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break ;
case AC3_OUTPUT_STEREO :
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nf = 1.0 / ( 1.0 + clev + slev ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 2 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = ( nf * clev ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * slev ) ;
ctx - > chcoeffs [ 4 ] * = ( nf * slev ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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nf = 1.0 / ( 1.0 + ( 3.0 * LEVEL_MINUS_3DB ) ) ;
ctx - > chcoeffs [ 0 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = nf ;
ctx - > chcoeffs [ 1 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 3 ] * = ( nf * LEVEL_MINUS_3DB ) ;
ctx - > chcoeffs [ 4 ] * = ( nf * LEVEL_MINUS_3DB ) ;
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break ;
}
break ;
}
}
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/*********** BEGIN DOWNMIX FUNCTIONS ***********/
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static inline void mix_dualmono_to_mono ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = output [ 2 ] [ i ] ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
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}
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static inline void mix_dualmono_to_stereo ( AC3DecodeContext * ctx )
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{
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int i ;
float tmp ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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tmp = output [ 1 ] [ i ] + output [ 2 ] [ i ] ;
output [ 1 ] [ i ] = output [ 2 ] [ i ] = tmp ;
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}
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}
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static inline void upmix_mono_to_stereo ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + )
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output [ 2 ] [ i ] = output [ 1 ] [ i ] ;
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}
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static inline void mix_stereo_to_mono ( AC3DecodeContext * ctx )
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{
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int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = output [ 2 ] [ i ] ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
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}
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static inline void mix_3f_to_mono ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] + output [ 3 ] [ i ] ) ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
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}
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static inline void mix_3f_to_stereo ( AC3DecodeContext * ctx )
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{
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int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = output [ 2 ] [ i ] ;
output [ 2 ] [ i ] + = output [ 3 ] [ i ] ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
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}
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static inline void mix_2f_1r_to_mono ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] + output [ 3 ] [ i ] ) ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
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}
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static inline void mix_2f_1r_to_stereo ( AC3DecodeContext * ctx )
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{
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int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = output [ 2 ] [ i ] ;
output [ 2 ] [ i ] + = output [ 3 ] [ i ] ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
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}
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static inline void mix_2f_1r_to_dolby ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] - = output [ 3 ] [ i ] ;
output [ 2 ] [ i ] + = output [ 3 ] [ i ] ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
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}
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static inline void mix_3f_1r_to_mono ( AC3DecodeContext * ctx )
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{
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int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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2007-07-14 17:42:15 +02:00
for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] = ( output [ 2 ] [ i ] + output [ 3 ] [ i ] + output [ 4 ] [ i ] ) ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_3f_1r_to_stereo ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] + output [ 4 ] [ i ] ) ;
output [ 2 ] [ i ] + = ( output [ 3 ] [ i ] + output [ 4 ] [ i ] ) ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_3f_1r_to_dolby ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] - output [ 4 ] [ i ] ) ;
output [ 2 ] [ i ] + = ( output [ 3 ] [ i ] + output [ 4 ] [ i ] ) ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_2f_2r_to_mono ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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2007-07-14 17:42:15 +02:00
for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] = ( output [ 2 ] [ i ] + output [ 3 ] [ i ] + output [ 4 ] [ i ] ) ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_2f_2r_to_stereo ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = output [ 3 ] [ i ] ;
output [ 2 ] [ i ] + = output [ 4 ] [ i ] ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_2f_2r_to_dolby ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] - = output [ 3 ] [ i ] ;
output [ 2 ] [ i ] + = output [ 4 ] [ i ] ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
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}
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static inline void mix_3f_2r_to_mono ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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2007-07-14 17:42:15 +02:00
for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] + output [ 3 ] [ i ] + output [ 4 ] [ i ] + output [ 5 ] [ i ] ) ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
memset ( output [ 5 ] , 0 , sizeof ( output [ 5 ] ) ) ;
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}
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static inline void mix_3f_2r_to_stereo ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
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for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] + output [ 4 ] [ i ] ) ;
output [ 2 ] [ i ] + = ( output [ 3 ] [ i ] + output [ 5 ] [ i ] ) ;
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}
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memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
memset ( output [ 5 ] , 0 , sizeof ( output [ 5 ] ) ) ;
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}
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static inline void mix_3f_2r_to_dolby ( AC3DecodeContext * ctx )
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{
int i ;
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float ( * output ) [ BLOCK_SIZE ] = ctx - > output ;
2007-07-14 17:38:39 +02:00
2007-07-14 17:41:27 +02:00
for ( i = 0 ; i < 256 ; i + + ) {
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output [ 1 ] [ i ] + = ( output [ 2 ] [ i ] - output [ 4 ] [ i ] - output [ 5 ] [ i ] ) ;
output [ 2 ] [ i ] + = ( output [ 3 ] [ i ] + output [ 4 ] [ i ] + output [ 5 ] [ i ] ) ;
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}
2007-07-14 17:42:15 +02:00
memset ( output [ 3 ] , 0 , sizeof ( output [ 3 ] ) ) ;
memset ( output [ 4 ] , 0 , sizeof ( output [ 4 ] ) ) ;
memset ( output [ 5 ] , 0 , sizeof ( output [ 5 ] ) ) ;
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}
2007-07-14 18:04:17 +02:00
/*********** END DOWNMIX FUNCTIONS ***********/
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2007-07-14 18:04:17 +02:00
/* Downmix the output.
* This function downmixes the output when the number of input
* channels is not equal to the number of output channels requested .
*/
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static void do_downmix ( AC3DecodeContext * ctx )
{
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int from = ctx - > acmod ;
int to = ctx - > blkoutput ;
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2007-07-14 18:04:17 +02:00
if ( to = = AC3_OUTPUT_UNMODIFIED )
return ;
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switch ( from ) {
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case AC3_ACMOD_DUALMONO :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_dualmono_to_mono ( ctx ) ;
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break ;
2007-07-14 17:48:28 +02:00
case AC3_OUTPUT_STEREO : /* We assume that sum of both mono channels is requested */
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mix_dualmono_to_stereo ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_MONO :
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switch ( to ) {
case AC3_OUTPUT_STEREO :
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upmix_mono_to_stereo ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_STEREO :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_stereo_to_mono ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_3F :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_3f_to_mono ( ctx ) ;
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break ;
case AC3_OUTPUT_STEREO :
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mix_3f_to_stereo ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_2F1R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_2f_1r_to_mono ( ctx ) ;
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break ;
case AC3_OUTPUT_STEREO :
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mix_2f_1r_to_stereo ( ctx ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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mix_2f_1r_to_dolby ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_3F1R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_3f_1r_to_mono ( ctx ) ;
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break ;
case AC3_OUTPUT_STEREO :
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mix_3f_1r_to_stereo ( ctx ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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mix_3f_1r_to_dolby ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_2F2R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_2f_2r_to_mono ( ctx ) ;
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break ;
case AC3_OUTPUT_STEREO :
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mix_2f_2r_to_stereo ( ctx ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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mix_2f_2r_to_dolby ( ctx ) ;
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break ;
}
break ;
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case AC3_ACMOD_3F2R :
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switch ( to ) {
case AC3_OUTPUT_MONO :
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mix_3f_2r_to_mono ( ctx ) ;
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break ;
case AC3_OUTPUT_STEREO :
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mix_3f_2r_to_stereo ( ctx ) ;
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break ;
case AC3_OUTPUT_DOLBY :
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mix_3f_2r_to_dolby ( ctx ) ;
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break ;
}
break ;
}
2007-07-14 17:38:39 +02:00
}
2007-07-14 18:04:17 +02:00
/* This function performs the imdct on 256 sample transform
* coefficients .
*/
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static void do_imdct_256 ( AC3DecodeContext * ctx , int chindex )
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{
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int i , k ;
float x [ 128 ] ;
FFTComplex z [ 2 ] [ 64 ] ;
float * o_ptr = ctx - > tmp_output ;
for ( i = 0 ; i < 2 ; i + + ) {
/* de-interleave coefficients */
for ( k = 0 ; k < 128 ; k + + ) {
x [ k ] = ctx - > transform_coeffs [ chindex ] [ 2 * k + i ] ;
}
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/* run standard IMDCT */
ctx - > imdct_256 . fft . imdct_calc ( & ctx - > imdct_256 , o_ptr , x , ctx - > tmp_imdct ) ;
/* reverse the post-rotation & reordering from standard IMDCT */
for ( k = 0 ; k < 32 ; k + + ) {
z [ i ] [ 32 + k ] . re = - o_ptr [ 128 + 2 * k ] ;
z [ i ] [ 32 + k ] . im = - o_ptr [ 2 * k ] ;
z [ i ] [ 31 - k ] . re = o_ptr [ 2 * k + 1 ] ;
z [ i ] [ 31 - k ] . im = o_ptr [ 128 + 2 * k + 1 ] ;
}
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}
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/* apply AC-3 post-rotation & reordering */
for ( k = 0 ; k < 64 ; k + + ) {
o_ptr [ 2 * k ] = - z [ 0 ] [ k ] . im ;
o_ptr [ 2 * k + 1 ] = z [ 0 ] [ 63 - k ] . re ;
o_ptr [ 128 + 2 * k ] = - z [ 0 ] [ k ] . re ;
o_ptr [ 128 + 2 * k + 1 ] = z [ 0 ] [ 63 - k ] . im ;
o_ptr [ 256 + 2 * k ] = - z [ 1 ] [ k ] . re ;
o_ptr [ 256 + 2 * k + 1 ] = z [ 1 ] [ 63 - k ] . im ;
o_ptr [ 384 + 2 * k ] = z [ 1 ] [ k ] . im ;
o_ptr [ 384 + 2 * k + 1 ] = - z [ 1 ] [ 63 - k ] . re ;
}
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}
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/* IMDCT Transform. */
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static inline void do_imdct ( AC3DecodeContext * ctx )
{
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int ch ;
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if ( ctx - > blkoutput & AC3_OUTPUT_LFEON ) {
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ctx - > imdct_512 . fft . imdct_calc ( & ctx - > imdct_512 , ctx - > tmp_output ,
ctx - > transform_coeffs [ 0 ] , ctx - > tmp_imdct ) ;
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}
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for ( ch = 1 ; ch < = ctx - > nfchans ; ch + + ) {
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if ( ctx - > blksw [ ch - 1 ] )
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do_imdct_256 ( ctx , ch ) ;
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else
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ctx - > imdct_512 . fft . imdct_calc ( & ctx - > imdct_512 , ctx - > tmp_output ,
ctx - > transform_coeffs [ ch ] ,
ctx - > tmp_imdct ) ;
ctx - > dsp . vector_fmul_add_add ( ctx - > output [ ch ] , ctx - > tmp_output ,
ctx - > window , ctx - > delay [ ch ] , 384 , 256 , 1 ) ;
ctx - > dsp . vector_fmul_reverse ( ctx - > delay [ ch ] , ctx - > tmp_output + 256 ,
ctx - > window , 256 ) ;
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}
}
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/* Parse the audio block from ac3 bitstream.
* This function extract the audio block from the ac3 bitstream
* and produces the output for the block . This function must
* be called for each of the six audio block in the ac3 bitstream .
*/
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static int ac3_parse_audio_block ( AC3DecodeContext * ctx , int blk )
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{
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int nfchans = ctx - > nfchans ;
int acmod = ctx - > acmod ;
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int i , bnd , rbnd , seg , grpsize ;
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GetBitContext * gb = & ctx - > gb ;
int bit_alloc_flags = 0 ;
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int8_t * dexps ;
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int mstrcplco , cplcoexp , cplcomant ;
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int dynrng , chbwcod , ngrps , cplabsexp , skipl ;
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for ( i = 0 ; i < nfchans ; i + + ) /*block switch flag */
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ctx - > blksw [ i ] = get_bits1 ( gb ) ;
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for ( i = 0 ; i < nfchans ; i + + ) /* dithering flag */
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ctx - > dithflag [ i ] = get_bits1 ( gb ) ;
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if ( get_bits1 ( gb ) ) { /* dynamic range */
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dynrng = get_sbits ( gb , 8 ) ;
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ctx - > dynrng = ( ( ( ( dynrng & 0x1f ) | 0x20 ) < < 13 ) * scale_factors [ 3 - ( dynrng > > 5 ) ] ) ;
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} else if ( blk = = 0 ) {
ctx - > dynrng = 1.0 ;
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}
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if ( acmod = = AC3_ACMOD_DUALMONO ) { /* dynamic range 1+1 mode */
if ( get_bits1 ( gb ) ) {
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dynrng = get_sbits ( gb , 8 ) ;
ctx - > dynrng2 = ( ( ( ( dynrng & 0x1f ) | 0x20 ) < < 13 ) * scale_factors [ 3 - ( dynrng > > 5 ) ] ) ;
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} else if ( blk = = 0 ) {
ctx - > dynrng2 = 1.0 ;
}
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}
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get_downmix_coeffs ( ctx ) ;
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if ( get_bits1 ( gb ) ) { /* coupling strategy */
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ctx - > cplinu = get_bits1 ( gb ) ;
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ctx - > cplbndstrc = 0 ;
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if ( ctx - > cplinu ) { /* coupling in use */
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for ( i = 0 ; i < nfchans ; i + + )
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ctx - > chincpl [ i ] = get_bits1 ( gb ) ;
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if ( acmod = = AC3_ACMOD_STEREO )
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ctx - > phsflginu = get_bits1 ( gb ) ; //phase flag in use
ctx - > cplbegf = get_bits ( gb , 4 ) ;
ctx - > cplendf = get_bits ( gb , 4 ) ;
if ( 3 + ctx - > cplendf - ctx - > cplbegf < 0 ) {
av_log ( NULL , AV_LOG_ERROR , " cplendf = %d < cplbegf = %d \n " , ctx - > cplendf , ctx - > cplbegf ) ;
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return - 1 ;
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}
ctx - > ncplbnd = ctx - > ncplsubnd = 3 + ctx - > cplendf - ctx - > cplbegf ;
ctx - > cplstrtmant = ctx - > cplbegf * 12 + 37 ;
ctx - > cplendmant = ctx - > cplendf * 12 + 73 ;
for ( i = 0 ; i < ctx - > ncplsubnd - 1 ; i + + ) /* coupling band structure */
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if ( get_bits1 ( gb ) ) {
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ctx - > cplbndstrc | = 1 < < i ;
ctx - > ncplbnd - - ;
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}
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} else {
for ( i = 0 ; i < nfchans ; i + + )
ctx - > chincpl [ i ] = 0 ;
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}
}
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if ( ctx - > cplinu ) {
ctx - > cplcoe = 0 ;
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for ( i = 0 ; i < nfchans ; i + + )
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if ( ctx - > chincpl [ i ] )
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if ( get_bits1 ( gb ) ) { /* coupling co-ordinates */
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ctx - > cplcoe | = 1 < < i ;
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mstrcplco = 3 * get_bits ( gb , 2 ) ;
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for ( bnd = 0 ; bnd < ctx - > ncplbnd ; bnd + + ) {
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cplcoexp = get_bits ( gb , 4 ) ;
cplcomant = get_bits ( gb , 4 ) ;
if ( cplcoexp = = 15 )
cplcomant < < = 14 ;
else
cplcomant = ( cplcomant | 0x10 ) < < 13 ;
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ctx - > cplco [ i ] [ bnd ] = cplcomant * scale_factors [ cplcoexp + mstrcplco ] ;
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}
}
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if ( acmod = = AC3_ACMOD_STEREO & & ctx - > phsflginu & & ( ctx - > cplcoe & 1 | | ctx - > cplcoe & 2 ) )
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for ( bnd = 0 ; bnd < ctx - > ncplbnd ; bnd + + )
if ( get_bits1 ( gb ) )
ctx - > cplco [ 1 ] [ bnd ] = - ctx - > cplco [ 1 ] [ bnd ] ;
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}
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if ( acmod = = AC3_ACMOD_STEREO ) { /* rematrixing */
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ctx - > rematstr = get_bits1 ( gb ) ;
if ( ctx - > rematstr ) {
if ( ! ( ctx - > cplinu ) | | ctx - > cplbegf > 2 )
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for ( rbnd = 0 ; rbnd < 4 ; rbnd + + )
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ctx - > rematflg [ rbnd ] = get_bits1 ( gb ) ;
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if ( ctx - > cplbegf > 0 & & ctx - > cplbegf < = 2 & & ctx - > cplinu )
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for ( rbnd = 0 ; rbnd < 3 ; rbnd + + )
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ctx - > rematflg [ rbnd ] = get_bits1 ( gb ) ;
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if ( ctx - > cplbegf = = 0 & & ctx - > cplinu )
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for ( rbnd = 0 ; rbnd < 2 ; rbnd + + )
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ctx - > rematflg [ rbnd ] = get_bits1 ( gb ) ;
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}
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}
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ctx - > cplexpstr = EXP_REUSE ;
ctx - > lfeexpstr = EXP_REUSE ;
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if ( ctx - > cplinu ) /* coupling exponent strategy */
ctx - > cplexpstr = get_bits ( gb , 2 ) ;
for ( i = 0 ; i < nfchans ; i + + ) /* channel exponent strategy */
ctx - > chexpstr [ i ] = get_bits ( gb , 2 ) ;
if ( ctx - > lfeon ) /* lfe exponent strategy */
ctx - > lfeexpstr = get_bits1 ( gb ) ;
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for ( i = 0 ; i < nfchans ; i + + ) /* channel bandwidth code */
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if ( ctx - > chexpstr [ i ] ! = EXP_REUSE ) {
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if ( ctx - > chincpl [ i ] )
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ctx - > endmant [ i ] = ctx - > cplstrtmant ;
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else {
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chbwcod = get_bits ( gb , 6 ) ;
if ( chbwcod > 60 ) {
av_log ( NULL , AV_LOG_ERROR , " chbwcod = %d > 60 " , chbwcod ) ;
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return - 1 ;
}
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ctx - > endmant [ i ] = chbwcod * 3 + 73 ;
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}
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}
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if ( ctx - > cplexpstr ! = EXP_REUSE ) { /* coupling exponents */
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bit_alloc_flags = 64 ;
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cplabsexp = get_bits ( gb , 4 ) < < 1 ;
ngrps = ( ctx - > cplendmant - ctx - > cplstrtmant ) / ( 3 < < ( ctx - > cplexpstr - 1 ) ) ;
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decode_exponents ( gb , ctx - > cplexpstr , ngrps , cplabsexp , ctx - > dcplexps + ctx - > cplstrtmant ) ;
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}
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for ( i = 0 ; i < nfchans ; i + + ) /* fbw channel exponents */
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if ( ctx - > chexpstr [ i ] ! = EXP_REUSE ) {
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bit_alloc_flags | = 1 < < i ;
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grpsize = 3 < < ( ctx - > chexpstr [ i ] - 1 ) ;
ngrps = ( ctx - > endmant [ i ] + grpsize - 4 ) / grpsize ;
dexps = ctx - > dexps [ i ] ;
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dexps [ 0 ] = get_bits ( gb , 4 ) ;
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decode_exponents ( gb , ctx - > chexpstr [ i ] , ngrps , dexps [ 0 ] , dexps + 1 ) ;
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skip_bits ( gb , 2 ) ; /* skip gainrng */
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}
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if ( ctx - > lfeexpstr ! = EXP_REUSE ) { /* lfe exponents */
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bit_alloc_flags | = 32 ;
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ctx - > dlfeexps [ 0 ] = get_bits ( gb , 4 ) ;
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decode_exponents ( gb , ctx - > lfeexpstr , 2 , ctx - > dlfeexps [ 0 ] , ctx - > dlfeexps + 1 ) ;
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}
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if ( get_bits1 ( gb ) ) { /* bit allocation information */
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bit_alloc_flags = 127 ;
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ctx - > sdcycod = get_bits ( gb , 2 ) ;
ctx - > fdcycod = get_bits ( gb , 2 ) ;
ctx - > sgaincod = get_bits ( gb , 2 ) ;
ctx - > dbpbcod = get_bits ( gb , 2 ) ;
ctx - > floorcod = get_bits ( gb , 3 ) ;
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}
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if ( get_bits1 ( gb ) ) { /* snroffset */
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bit_alloc_flags = 127 ;
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ctx - > csnroffst = get_bits ( gb , 6 ) ;
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if ( ctx - > cplinu ) { /* coupling fine snr offset and fast gain code */
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ctx - > cplfsnroffst = get_bits ( gb , 4 ) ;
ctx - > cplfgaincod = get_bits ( gb , 3 ) ;
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}
for ( i = 0 ; i < nfchans ; i + + ) { /* channel fine snr offset and fast gain code */
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ctx - > fsnroffst [ i ] = get_bits ( gb , 4 ) ;
ctx - > fgaincod [ i ] = get_bits ( gb , 3 ) ;
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}
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if ( ctx - > lfeon ) { /* lfe fine snr offset and fast gain code */
ctx - > lfefsnroffst = get_bits ( gb , 4 ) ;
ctx - > lfefgaincod = get_bits ( gb , 3 ) ;
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}
}
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if ( ctx - > cplinu & & get_bits1 ( gb ) ) { /* coupling leak information */
bit_alloc_flags | = 64 ;
ctx - > cplfleak = get_bits ( gb , 3 ) ;
ctx - > cplsleak = get_bits ( gb , 3 ) ;
}
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if ( get_bits1 ( gb ) ) { /* delta bit allocation information */
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bit_alloc_flags = 127 ;
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if ( ctx - > cplinu ) {
ctx - > cpldeltbae = get_bits ( gb , 2 ) ;
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if ( ctx - > cpldeltbae = = DBA_RESERVED ) {
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av_log ( NULL , AV_LOG_ERROR , " coupling delta bit allocation strategy reserved \n " ) ;
return - 1 ;
}
}
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for ( i = 0 ; i < nfchans ; i + + ) {
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ctx - > deltbae [ i ] = get_bits ( gb , 2 ) ;
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if ( ctx - > deltbae [ i ] = = DBA_RESERVED ) {
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av_log ( NULL , AV_LOG_ERROR , " delta bit allocation strategy reserved \n " ) ;
return - 1 ;
}
}
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if ( ctx - > cplinu )
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if ( ctx - > cpldeltbae = = DBA_NEW ) { /*coupling delta offset, len and bit allocation */
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ctx - > cpldeltnseg = get_bits ( gb , 3 ) ;
for ( seg = 0 ; seg < = ctx - > cpldeltnseg ; seg + + ) {
ctx - > cpldeltoffst [ seg ] = get_bits ( gb , 5 ) ;
ctx - > cpldeltlen [ seg ] = get_bits ( gb , 4 ) ;
ctx - > cpldeltba [ seg ] = get_bits ( gb , 3 ) ;
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}
}
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for ( i = 0 ; i < nfchans ; i + + )
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if ( ctx - > deltbae [ i ] = = DBA_NEW ) { /*channel delta offset, len and bit allocation */
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ctx - > deltnseg [ i ] = get_bits ( gb , 3 ) ;
for ( seg = 0 ; seg < = ctx - > deltnseg [ i ] ; seg + + ) {
ctx - > deltoffst [ i ] [ seg ] = get_bits ( gb , 5 ) ;
ctx - > deltlen [ i ] [ seg ] = get_bits ( gb , 4 ) ;
ctx - > deltba [ i ] [ seg ] = get_bits ( gb , 3 ) ;
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}
}
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} else if ( blk = = 0 ) {
if ( ctx - > cplinu )
ctx - > cpldeltbae = DBA_NONE ;
for ( i = 0 ; i < nfchans ; i + + ) {
ctx - > deltbae [ i ] = DBA_NONE ;
}
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}
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if ( bit_alloc_flags ) {
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/* set bit allocation parameters */
ctx - > bit_alloc_params . sdecay = ff_sdecaytab [ ctx - > sdcycod ] ;
ctx - > bit_alloc_params . fdecay = ff_fdecaytab [ ctx - > fdcycod ] ;
ctx - > bit_alloc_params . sgain = ff_sgaintab [ ctx - > sgaincod ] ;
ctx - > bit_alloc_params . dbknee = ff_dbkneetab [ ctx - > dbpbcod ] ;
ctx - > bit_alloc_params . floor = ff_floortab [ ctx - > floorcod ] ;
ctx - > bit_alloc_params . cplfleak = ctx - > cplfleak ;
ctx - > bit_alloc_params . cplsleak = ctx - > cplsleak ;
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if ( ctx - > cplinu & & ( bit_alloc_flags & 64 ) )
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do_bit_allocation ( ctx , 5 ) ;
for ( i = 0 ; i < nfchans ; i + + )
if ( ( bit_alloc_flags > > i ) & 1 )
do_bit_allocation ( ctx , i ) ;
if ( ctx - > lfeon & & ( bit_alloc_flags & 32 ) )
do_bit_allocation ( ctx , 6 ) ;
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}
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if ( get_bits1 ( gb ) ) { /* unused dummy data */
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skipl = get_bits ( gb , 9 ) ;
while ( skipl - - )
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skip_bits ( gb , 8 ) ;
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}
/* unpack the transform coefficients
* * this also uncouples channels if coupling is in use .
*/
if ( get_transform_coeffs ( ctx ) ) {
av_log ( NULL , AV_LOG_ERROR , " Error in routine get_transform_coeffs \n " ) ;
return - 1 ;
}
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/* recover coefficients if rematrixing is in use */
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if ( ctx - > acmod = = AC3_ACMOD_STEREO )
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do_rematrixing ( ctx ) ;
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do_downmix ( ctx ) ;
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do_imdct ( ctx ) ;
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return 0 ;
}
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static inline int16_t convert ( int32_t i )
{
if ( i > 0x43c07fff )
return 32767 ;
else if ( i < = 0x43bf8000 )
return - 32768 ;
else
return ( i - 0x43c00000 ) ;
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}
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/* Decode ac3 frame.
*
* @ param avctx Pointer to AVCodecContext
* @ param data Pointer to pcm smaples
* @ param data_size Set to number of pcm samples produced by decoding
* @ param buf Data to be decoded
* @ param buf_size Size of the buffer
*/
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static int ac3_decode_frame ( AVCodecContext * avctx , void * data , int * data_size , uint8_t * buf , int buf_size )
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{
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AC3DecodeContext * ctx = ( AC3DecodeContext * ) avctx - > priv_data ;
int16_t * out_samples = ( int16_t * ) data ;
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int i , j , k , start ;
int32_t * int_ptr [ 6 ] ;
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for ( i = 0 ; i < 6 ; i + + )
int_ptr [ i ] = ( int32_t * ) ( & ctx - > output [ i ] ) ;
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//Initialize the GetBitContext with the start of valid AC3 Frame.
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init_get_bits ( & ctx - > gb , buf , buf_size * 8 ) ;
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//Parse the syncinfo.
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if ( ac3_parse_header ( ctx ) ) {
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av_log ( avctx , AV_LOG_ERROR , " \n " ) ;
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* data_size = 0 ;
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return buf_size ;
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}
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avctx - > sample_rate = ctx - > sampling_rate ;
avctx - > bit_rate = ctx - > bit_rate ;
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if ( avctx - > channels = = 0 ) {
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ctx - > blkoutput | = AC3_OUTPUT_UNMODIFIED ;
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if ( ctx - > lfeon )
ctx - > blkoutput | = AC3_OUTPUT_LFEON ;
avctx - > channels = ctx - > nfchans + ctx - > lfeon ;
}
else if ( avctx - > channels = = 1 )
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ctx - > blkoutput | = AC3_OUTPUT_MONO ;
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else if ( avctx - > channels = = 2 ) {
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if ( ctx - > dsurmod = = 0x02 )
ctx - > blkoutput | = AC3_OUTPUT_DOLBY ;
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else
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ctx - > blkoutput | = AC3_OUTPUT_STEREO ;
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}
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else {
if ( avctx - > channels < ( ctx - > nfchans + ctx - > lfeon ) )
av_log ( avctx , AV_LOG_INFO , " ac3_decoder: AC3 Source Channels Are Less Then Specified %d: Output to %d Channels \n " , avctx - > channels , ctx - > nfchans + ctx - > lfeon ) ;
ctx - > blkoutput | = AC3_OUTPUT_UNMODIFIED ;
if ( ctx - > lfeon )
ctx - > blkoutput | = AC3_OUTPUT_LFEON ;
avctx - > channels = ctx - > nfchans + ctx - > lfeon ;
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}
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//av_log(avctx, AV_LOG_INFO, "channels = %d \t bit rate = %d \t sampling rate = %d \n", avctx->channels, avctx->bit_rate * 1000, avctx->sample_rate);
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//Parse the Audio Blocks.
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for ( i = 0 ; i < NB_BLOCKS ; i + + ) {
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if ( ac3_parse_audio_block ( ctx , i ) ) {
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av_log ( avctx , AV_LOG_ERROR , " error parsing the audio block \n " ) ;
* data_size = 0 ;
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return ctx - > frame_size ;
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}
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start = ( ctx - > blkoutput & AC3_OUTPUT_LFEON ) ? 0 : 1 ;
for ( k = 0 ; k < BLOCK_SIZE ; k + + )
for ( j = start ; j < = avctx - > channels ; j + + )
* ( out_samples + + ) = convert ( int_ptr [ j ] [ k ] ) ;
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}
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* data_size = NB_BLOCKS * BLOCK_SIZE * avctx - > channels * sizeof ( int16_t ) ;
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return ctx - > frame_size ;
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}
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/* Uninitialize ac3 decoder.
*/
static int ac3_decode_end ( AVCodecContext * avctx )
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{
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AC3DecodeContext * ctx = ( AC3DecodeContext * ) avctx - > priv_data ;
ff_mdct_end ( & ctx - > imdct_512 ) ;
ff_mdct_end ( & ctx - > imdct_256 ) ;
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return 0 ;
}
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AVCodec ac3_decoder = {
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. name = " ac3 " ,
. type = CODEC_TYPE_AUDIO ,
. id = CODEC_ID_AC3 ,
. priv_data_size = sizeof ( AC3DecodeContext ) ,
. init = ac3_decode_init ,
. close = ac3_decode_end ,
. decode = ac3_decode_frame ,
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} ;