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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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*
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* For exponent decoding the code is inspired by the code in liba52 by
* Michel Lespinasse and Aaron Holtzman .
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* http : //liba52.sourceforge.net
*
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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>
# define ALT_BITSTREAM_READER
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# include "avcodec.h"
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# include "ac3.h"
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# include "ac3tab.h"
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# include "bitstream.h"
# include "dsputil.h"
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# include "random.h"
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static uint8_t bndtab [ 51 ] ;
static uint8_t masktab [ 253 ] ;
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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 ] ;
static int16_t psdtab [ 25 ] ;
static int8_t exp_1 [ 128 ] ;
static int8_t exp_2 [ 128 ] ;
static int8_t exp_3 [ 128 ] ;
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 N 512 /* constant for IMDCT Block size */
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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 {
uint16_t crc1 ;
uint8_t fscod ;
uint8_t acmod ;
uint8_t cmixlev ;
uint8_t surmixlev ;
uint8_t dsurmod ;
uint8_t blksw ;
uint8_t dithflag ;
uint8_t cplinu ;
uint8_t chincpl ;
uint8_t phsflginu ;
uint8_t cplbegf ;
uint8_t cplendf ;
uint8_t cplcoe ;
uint32_t cplbndstrc ;
uint8_t rematstr ;
uint8_t rematflg ;
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 ] ;
uint8_t deltnseg [ 5 ] ;
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 nfchans ; //number of channels
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
uint8_t dcplexps [ 256 ] ; //decoded coupling exponents
uint8_t dexps [ 5 ] [ 256 ] ; //decoded fbw channel exponents
uint8_t dlfeexps [ 256 ] ; //decoded lfe channel exponents
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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{
int i , j , k , l , v ;
/* compute bndtab and masktab from bandsz */
k = 0 ;
l = 0 ;
for ( i = 0 ; i < 50 ; i + + ) {
bndtab [ i ] = l ;
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v = ff_ac3_bndsz [ i ] ;
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for ( j = 0 ; j < v ; j + + ) masktab [ k + + ] = i ;
l + = v ;
}
masktab [ 253 ] = masktab [ 254 ] = masktab [ 255 ] = 0 ;
bndtab [ 50 ] = 0 ;
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/* PSD Table For Mapping Exponents To PSD. */
for ( i = 0 ; i < 25 ; i + + )
psdtab [ i ] = 3072 - ( i < < 7 ) ;
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/* Exponent Decoding Tables */
for ( i = 0 ; i < 5 ; i + + ) {
v = i - 2 ;
for ( j = 0 ; j < 25 ; j + + )
exp_1 [ i * 25 + j ] = v ;
}
for ( i = 0 ; i < 25 ; i + + ) {
v = ( i % 5 ) - 2 ;
for ( j = 0 ; j < 5 ; j + + )
exp_2 [ i * 5 + j ] = v ;
}
for ( i = 0 ; i < 25 ; i + + ) {
v = - 2 ;
for ( j = 0 ; j < 5 ; j + + )
exp_3 [ i * 5 + j ] = v + + ;
}
for ( i = 125 ; i < 128 ; i + + )
exp_1 [ i ] = exp_2 [ i ] = exp_3 [ i ] = 25 ;
/* End Exponent Decoding Tables */
/* 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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}
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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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/* Synchronize to ac3 bitstream.
* This function searches for the syncword ' 0xb77 ' .
*
* @ param buf Pointer to " probable " ac3 bitstream buffer
* @ param buf_size Size of buffer
* @ return Returns the position where syncword is found , - 1 if no syncword is found
*/
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static int ac3_synchronize ( uint8_t * buf , int buf_size )
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{
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int i ;
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for ( i = 0 ; i < buf_size - 1 ; i + + )
if ( buf [ i ] = = 0x0b & & buf [ i + 1 ] = = 0x77 )
return i ;
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return - 1 ;
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}
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/* Parse the 'sync_info' from the ac3 bitstream.
* This function extracts the sync_info from ac3 bitstream .
* GetBitContext within AC3DecodeContext must point to
* start of the synchronized ac3 bitstream .
*
* @ param ctx AC3DecodeContext
* @ return Returns framesize , returns 0 if fscod , frmsizecod or bsid is not valid
*/
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static int ac3_parse_sync_info ( AC3DecodeContext * ctx )
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{
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GetBitContext * gb = & ctx - > gb ;
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int frmsizecod , bsid ;
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skip_bits ( gb , 16 ) ; //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
ctx - > crc1 = get_bits ( gb , 16 ) ;
ctx - > fscod = get_bits ( gb , 2 ) ;
if ( ctx - > fscod = = 0x03 )
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return 0 ;
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frmsizecod = get_bits ( gb , 6 ) ;
if ( frmsizecod > = 38 )
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return 0 ;
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ctx - > sampling_rate = ff_ac3_freqs [ ctx - > fscod ] ;
ctx - > bit_rate = ff_ac3_bitratetab [ frmsizecod > > 1 ] ;
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/* we include it here in order to determine validity of ac3 frame */
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bsid = get_bits ( gb , 5 ) ;
if ( bsid > 0x08 )
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return 0 ;
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skip_bits ( gb , 3 ) ; //skip the bsmod, bsi->bsmod = get_bits(gb, 3);
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switch ( ctx - > fscod ) {
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case 0x00 :
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ctx - > frame_size = 4 * ctx - > bit_rate ;
return ctx - > frame_size ;
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case 0x01 :
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ctx - > frame_size = 2 * ( 320 * ctx - > bit_rate / 147 + ( frmsizecod & 1 ) ) ;
return ctx - > frame_size ;
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case 0x02 :
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ctx - > frame_size = 6 * ctx - > bit_rate ;
return ctx - > frame_size ;
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}
/* never reached */
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return 0 ;
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}
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/* Parse bsi from ac3 bitstream.
* This function extracts the bitstream information ( bsi ) from ac3 bitstream .
*
* @ param ctx AC3DecodeContext after processed by ac3_parse_sync_info
*/
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static void ac3_parse_bsi ( AC3DecodeContext * ctx )
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{
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GetBitContext * gb = & ctx - > gb ;
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int i ;
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ctx - > cmixlev = 0 ;
ctx - > surmixlev = 0 ;
ctx - > dsurmod = 0 ;
ctx - > nfchans = 0 ;
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ctx - > cpldeltbae = DBA_NONE ;
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ctx - > cpldeltnseg = 0 ;
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for ( i = 0 ; i < 5 ; i + + ) {
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ctx - > deltbae [ i ] = DBA_NONE ;
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ctx - > deltnseg [ i ] = 0 ;
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}
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ctx - > dynrng = 1.0 ;
ctx - > dynrng2 = 1.0 ;
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ctx - > acmod = get_bits ( gb , 3 ) ;
ctx - > nfchans = nfchans_tbl [ ctx - > acmod ] ;
if ( ctx - > acmod & 0x01 & & ctx - > acmod ! = 0x01 )
ctx - > cmixlev = get_bits ( gb , 2 ) ;
if ( ctx - > acmod & 0x04 )
ctx - > surmixlev = get_bits ( gb , 2 ) ;
if ( ctx - > acmod = = 0x02 )
ctx - > dsurmod = get_bits ( gb , 2 ) ;
ctx - > lfeon = get_bits1 ( gb ) ;
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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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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}
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/* Decodes the grouped exponents.
* This function decodes the coded exponents according to exponent strategy
* and stores them in the decoded exponents buffer .
*
* @ param gb GetBitContext which points to start of coded exponents
* @ param expstr Exponent coding strategy
* @ param ngrps Number of grouped exponetns
* @ param absexp Absolute exponent
* @ param dexps Decoded exponents are stored in dexps
* @ return Returns 0 if exponents are decoded successfully , - 1 if error occurs
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*/
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static int decode_exponents ( GetBitContext * gb , int expstr , int ngrps , uint8_t absexp , uint8_t * dexps )
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{
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int exps ;
while ( ngrps - - ) {
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exps = get_bits ( gb , 7 ) ;
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absexp + = exp_1 [ exps ] ;
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if ( absexp > 24 ) {
av_log ( NULL , AV_LOG_ERROR , " Absolute Exponent > 24, ngrp = %d \n " , ngrps ) ;
return - ngrps ;
}
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switch ( expstr ) {
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case EXP_D45 :
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* ( dexps + + ) = absexp ;
* ( dexps + + ) = absexp ;
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case EXP_D25 :
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* ( dexps + + ) = absexp ;
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case EXP_D15 :
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* ( dexps + + ) = absexp ;
}
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absexp + = exp_2 [ exps ] ;
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if ( absexp > 24 ) {
av_log ( NULL , AV_LOG_ERROR , " Absolute Exponent > 24, ngrp = %d \n " , ngrps ) ;
return - ngrps ;
}
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switch ( expstr ) {
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case EXP_D45 :
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* ( dexps + + ) = absexp ;
* ( dexps + + ) = absexp ;
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case EXP_D25 :
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* ( dexps + + ) = absexp ;
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case EXP_D15 :
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* ( dexps + + ) = absexp ;
}
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absexp + = exp_3 [ exps ] ;
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if ( absexp > 24 ) {
av_log ( NULL , AV_LOG_ERROR , " Absolute Exponent > 24, ngrp = %d \n " , ngrps ) ;
return - ngrps ;
}
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switch ( expstr ) {
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case EXP_D45 :
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* ( dexps + + ) = absexp ;
* ( dexps + + ) = absexp ;
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case EXP_D25 :
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* ( dexps + + ) = absexp ;
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case EXP_D15 :
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* ( dexps + + ) = absexp ;
}
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}
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return 0 ;
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}
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/*********** HELPER FUNCTIONS FOR BIT ALLOCATION ***********/
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static inline int logadd ( int a , int b )
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{
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int c = a - b ;
int address ;
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address = FFMIN ( ( FFABS ( c ) > > 1 ) , 255 ) ;
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if ( c > = 0 )
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return ( a + ff_ac3_latab [ address ] ) ;
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else
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return ( b + ff_ac3_latab [ address ] ) ;
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}
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static inline int calc_lowcomp ( int a , int b0 , int b1 , int bin )
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{
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if ( bin < 7 ) {
if ( ( b0 + 256 ) = = b1 )
a = 384 ;
else if ( b0 > b1 )
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a = FFMAX ( 0 , ( a - 64 ) ) ;
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}
else if ( bin < 20 ) {
if ( ( b0 + 256 ) = = b1 )
a = 320 ;
else if ( b0 > b1 )
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a = FFMAX ( 0 , ( a - 64 ) ) ;
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}
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else
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a = FFMAX ( 0 , ( a - 128 ) ) ;
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return a ;
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}
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/*********** END HELPER FUNCTIONS FOR BIT ALLOCATION ***********/
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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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int16_t psd [ 256 ] , bndpsd [ 50 ] , excite [ 50 ] , mask [ 50 ] , delta ;
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int sdecay , fdecay , sgain , dbknee , floor ;
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int lowcomp = 0 , fgain = 0 , snroffset = 0 , fastleak = 0 , slowleak = 0 , do_delta = 0 ;
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int start = 0 , end = 0 , bin = 0 , i = 0 , j = 0 , k = 0 , lastbin = 0 , bndstrt = 0 ;
int bndend = 0 , begin = 0 , deltnseg = 0 , band = 0 , seg = 0 , address = 0 ;
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int fscod = ctx - > fscod ;
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uint8_t * deltoffst = 0 , * deltlen = 0 , * deltba = 0 ;
uint8_t * exps = 0 , * bap = 0 ;
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/* initialization */
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sdecay = ff_sdecaytab [ ctx - > sdcycod ] ;
fdecay = ff_fdecaytab [ ctx - > fdcycod ] ;
sgain = ff_sgaintab [ ctx - > sgaincod ] ;
dbknee = ff_dbkneetab [ ctx - > dbpbcod ] ;
floor = ff_floortab [ ctx - > floorcod ] ;
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if ( chnl = = 5 ) {
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start = ctx - > cplstrtmant ;
end = ctx - > cplendmant ;
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fgain = ff_fgaintab [ ctx - > cplfgaincod ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > cplfsnroffst ) < < 2 ;
fastleak = ( ctx - > cplfleak < < 8 ) + 768 ;
slowleak = ( ctx - > cplsleak < < 8 ) + 768 ;
exps = ctx - > dcplexps ;
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bap = ctx - > cplbap ;
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if ( ctx - > cpldeltbae = = DBA_NEW | | ctx - > deltbae = = DBA_REUSE ) {
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do_delta = 1 ;
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deltnseg = ctx - > cpldeltnseg ;
deltoffst = ctx - > cpldeltoffst ;
deltlen = ctx - > cpldeltlen ;
deltba = ctx - > cpldeltba ;
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}
}
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else if ( chnl = = 6 ) {
start = 0 ;
end = 7 ;
lowcomp = 0 ;
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fastleak = 0 ;
slowleak = 0 ;
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fgain = ff_fgaintab [ ctx - > lfefgaincod ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > lfefsnroffst ) < < 2 ;
exps = ctx - > dlfeexps ;
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bap = ctx - > lfebap ;
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}
else {
start = 0 ;
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end = ctx - > endmant [ chnl ] ;
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lowcomp = 0 ;
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fastleak = 0 ;
slowleak = 0 ;
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fgain = ff_fgaintab [ ctx - > fgaincod [ chnl ] ] ;
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snroffset = ( ( ( ctx - > csnroffst - 15 ) < < 4 ) + ctx - > fsnroffst [ chnl ] ) < < 2 ;
exps = ctx - > dexps [ chnl ] ;
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bap = ctx - > bap [ chnl ] ;
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if ( ctx - > deltbae [ chnl ] = = DBA_NEW | | ctx - > deltbae [ chnl ] = = DBA_REUSE ) {
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do_delta = 1 ;
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deltnseg = ctx - > deltnseg [ chnl ] ;
deltoffst = ctx - > deltoffst [ chnl ] ;
deltlen = ctx - > deltlen [ chnl ] ;
deltba = ctx - > deltba [ chnl ] ;
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}
}
for ( bin = start ; bin < end ; bin + + ) /* exponent mapping into psd */
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psd [ bin ] = psdtab [ exps [ bin ] ] ;
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/* psd integration */
j = start ;
k = masktab [ start ] ;
do {
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lastbin = FFMIN ( ( bndtab [ k ] + ff_ac3_bndsz [ k ] ) , end ) ;
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bndpsd [ k ] = psd [ j ] ;
j + + ;
for ( i = j ; i < lastbin ; i + + ) {
bndpsd [ k ] = logadd ( bndpsd [ k ] , psd [ j ] ) ;
j + + ;
}
k + + ;
} while ( end > lastbin ) ;
/* compute the excite function */
bndstrt = masktab [ start ] ;
bndend = masktab [ end - 1 ] + 1 ;
if ( bndstrt = = 0 ) {
lowcomp = calc_lowcomp ( lowcomp , bndpsd [ 0 ] , bndpsd [ 1 ] , 0 ) ;
excite [ 0 ] = bndpsd [ 0 ] - fgain - lowcomp ;
lowcomp = calc_lowcomp ( lowcomp , bndpsd [ 1 ] , bndpsd [ 2 ] , 1 ) ;
excite [ 1 ] = bndpsd [ 1 ] - fgain - lowcomp ;
begin = 7 ;
for ( bin = 2 ; bin < 7 ; bin + + ) {
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if ( ( bndend ! = 7 ) | | ( bin ! = 6 ) )
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lowcomp = calc_lowcomp ( lowcomp , bndpsd [ bin ] , bndpsd [ bin + 1 ] , bin ) ;
fastleak = bndpsd [ bin ] - fgain ;
slowleak = bndpsd [ bin ] - sgain ;
excite [ bin ] = fastleak - lowcomp ;
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if ( ( bndend ! = 7 ) | | ( bin ! = 6 ) )
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if ( bndpsd [ bin ] < = bndpsd [ bin + 1 ] ) {
begin = bin + 1 ;
break ;
}
}
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for ( bin = begin ; bin < FFMIN ( bndend , 22 ) ; bin + + ) {
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if ( ( bndend ! = 7 ) | | ( bin ! = 6 ) )
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lowcomp = calc_lowcomp ( lowcomp , bndpsd [ bin ] , bndpsd [ bin + 1 ] , bin ) ;
fastleak - = fdecay ;
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fastleak = FFMAX ( fastleak , ( bndpsd [ bin ] - fgain ) ) ;
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slowleak - = sdecay ;
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slowleak = FFMAX ( slowleak , ( bndpsd [ bin ] - sgain ) ) ;
excite [ bin ] = FFMAX ( ( fastleak - lowcomp ) , slowleak ) ;
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}
begin = 22 ;
}
else {
begin = bndstrt ;
}
for ( bin = begin ; bin < bndend ; bin + + ) {
fastleak - = fdecay ;
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fastleak = FFMAX ( fastleak , ( bndpsd [ bin ] - fgain ) ) ;
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slowleak - = sdecay ;
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slowleak = FFMAX ( slowleak , ( bndpsd [ bin ] - sgain ) ) ;
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excite [ bin ] = FFMAX ( fastleak , slowleak ) ;
}
/* compute the masking curve */
for ( bin = bndstrt ; bin < bndend ; bin + + ) {
if ( bndpsd [ bin ] < dbknee )
excite [ bin ] + = ( ( dbknee - bndpsd [ bin ] ) > > 2 ) ;
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mask [ bin ] = FFMAX ( excite [ bin ] , ff_ac3_hth [ bin ] [ fscod ] ) ;
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}
/* apply the delta bit allocation */
if ( do_delta ) {
band = 0 ;
for ( seg = 0 ; seg < deltnseg + 1 ; seg + + ) {
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band + = deltoffst [ seg ] ;
if ( deltba [ seg ] > = 4 )
delta = ( deltba [ seg ] - 3 ) < < 7 ;
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else
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delta = ( deltba [ seg ] - 4 ) < < 7 ;
for ( k = 0 ; k < deltlen [ seg ] ; k + + ) {
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mask [ band ] + = delta ;
band + + ;
}
}
}
/*compute the bit allocation */
i = start ;
j = masktab [ start ] ;
do {
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lastbin = FFMIN ( ( bndtab [ j ] + ff_ac3_bndsz [ j ] ) , end ) ;
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mask [ j ] - = snroffset ;
mask [ j ] - = floor ;
if ( mask [ j ] < 0 )
mask [ j ] = 0 ;
mask [ j ] & = 0x1fe0 ;
mask [ j ] + = floor ;
for ( k = i ; k < lastbin ; k + + ) {
address = ( psd [ i ] - mask [ j ] ) > > 5 ;
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address = FFMIN ( 63 , ( FFMAX ( 0 , address ) ) ) ;
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bap [ i ] = ff_ac3_baptab [ address ] ;
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i + + ;
}
j + + ;
} while ( end > lastbin ) ;
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}
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/* Check if snroffsets are zero. */
static int is_snr_offsets_zero ( AC3DecodeContext * ctx )
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{
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int i ;
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if ( ( ctx - > csnroffst ) | | ( ctx - > cplinu & & ctx - > cplfsnroffst ) | |
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( ctx - > lfeon & & ctx - > lfefsnroffst ) )
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return 0 ;
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for ( i = 0 ; i < ctx - > nfchans ; i + + )
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if ( ctx - > fsnroffst [ i ] )
return 0 ;
return 1 ;
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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 ;
# define TRANSFORM_COEFF(tc, m, e, f) (tc) = (m) * (f)[(e)]
/* 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 ) & 1 ) {
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if ( ( ctx - > dithflag > > ch ) & 1 ) {
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TRANSFORM_COEFF ( cplcoeff , av_random ( & ctx - > dith_state ) & 0xFFFF , exps [ start ] , scale_factors ) ;
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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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TRANSFORM_COEFF ( cplcoeff , m - > l3_quantizers [ m - > l3ptr + + ] , exps [ start ] , scale_factors ) ;
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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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TRANSFORM_COEFF ( cplcoeff , m - > l5_quantizers [ m - > l5ptr + + ] , exps [ start ] , scale_factors ) ;
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break ;
case 3 :
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TRANSFORM_COEFF ( cplcoeff , l7_quantizers [ get_bits ( gb , 3 ) ] , exps [ start ] , scale_factors ) ;
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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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TRANSFORM_COEFF ( cplcoeff , m - > l11_quantizers [ m - > l11ptr + + ] , exps [ start ] , scale_factors ) ;
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break ;
case 5 :
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TRANSFORM_COEFF ( cplcoeff , l15_quantizers [ get_bits ( gb , 4 ) ] , exps [ start ] , scale_factors ) ;
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break ;
default :
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TRANSFORM_COEFF ( cplcoeff , get_sbits ( gb , qntztab [ tbap ] ) < < ( 16 - qntztab [ tbap ] ) ,
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exps [ start ] , scale_factors ) ;
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}
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for ( ch = 0 ; ch < ctx - > nfchans ; ch + + )
if ( ( ctx - > chincpl > > ch ) & 1 )
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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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2007-07-14 17:48:28 +02:00
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 */
dithflag = ( ctx - > dithflag > > ch_index ) & 1 ;
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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TRANSFORM_COEFF ( coeffs [ i ] , av_random ( & ctx - > dith_state ) & 0xFFFF , exps [ i ] , factors ) ;
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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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TRANSFORM_COEFF ( coeffs [ i ] , m - > l3_quantizers [ m - > l3ptr + + ] , exps [ i ] , factors ) ;
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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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TRANSFORM_COEFF ( coeffs [ i ] , m - > l5_quantizers [ m - > l5ptr + + ] , exps [ i ] , factors ) ;
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continue ;
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case 3 :
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TRANSFORM_COEFF ( coeffs [ i ] , l7_quantizers [ get_bits ( gb , 3 ) ] , exps [ i ] , factors ) ;
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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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TRANSFORM_COEFF ( coeffs [ i ] , m - > l11_quantizers [ m - > l11ptr + + ] , exps [ i ] , factors ) ;
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continue ;
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case 5 :
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TRANSFORM_COEFF ( coeffs [ i ] , l15_quantizers [ get_bits ( gb , 4 ) ] , exps [ i ] , factors ) ;
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continue ;
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default :
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TRANSFORM_COEFF ( coeffs [ i ] , get_sbits ( gb , qntztab [ tbap ] ) < < ( 16 - qntztab [ tbap ] ) , exps [ i ] , factors ) ;
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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 ) & 1 ) {
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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 & 1 )
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do_rematrixing1 ( ctx , bnd1 , bnd2 ) ;
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if ( ctx - > rematflg & 2 )
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do_rematrixing1 ( ctx , bnd2 , bnd3 ) ;
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bndend = bnd4 ;
if ( bndend > end ) {
bndend = end ;
if ( ctx - > rematflg & 4 )
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do_rematrixing1 ( ctx , bnd3 , bndend ) ;
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} else {
if ( ctx - > rematflg & 4 )
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do_rematrixing1 ( ctx , bnd3 , bnd4 ) ;
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if ( ctx - > rematflg & 8 )
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 ) ;
2007-07-14 17:41:27 +02:00
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 ) ;
2007-07-14 17:41:27 +02:00
break ;
}
break ;
}
}
2007-07-14 17:38:39 +02:00
2007-07-14 18:04:17 +02:00
/*********** 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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2007-07-14 17:42:15 +02:00
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 ;
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 [ 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 ;
2007-07-14 17:38:39 +02:00
2007-07-14 17:42:15 +02:00
for ( i = 0 ; i < 256 ; i + + )
output [ 1 ] [ i ] + = output [ 2 ] [ i ] ;
memset ( output [ 2 ] , 0 , sizeof ( output [ 2 ] ) ) ;
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}
2007-07-14 17:38:39 +02:00
2007-07-14 17:42:15 +02:00
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 ;
2007-07-14 17:38:39 +02:00
2007-07-14 17:42:15 +02:00
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 ;
2007-07-14 17:38:39 +02:00
2007-07-14 17:41:27 +02:00
for ( i = 0 ; i < 256 ; i + + ) {
2007-07-14 17:42:15 +02:00
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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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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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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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 ;
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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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}
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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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/*********** END DOWNMIX FUNCTIONS ***********/
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/* 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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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 ;
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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 ;
}
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}
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/* 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 k ;
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float x1 [ 128 ] , x2 [ 128 ] ;
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float * o_ptr , * d_ptr , * w ;
FFTComplex * ptr1 , * ptr2 ;
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for ( k = 0 ; k < N / 4 ; k + + ) {
x1 [ k ] = ctx - > transform_coeffs [ chindex ] [ 2 * k ] ;
x2 [ k ] = ctx - > transform_coeffs [ chindex ] [ 2 * k + 1 ] ;
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}
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ctx - > imdct_256 . fft . imdct_calc ( & ctx - > imdct_256 , ctx - > tmp_output , x1 , ctx - > tmp_imdct ) ;
ctx - > imdct_256 . fft . imdct_calc ( & ctx - > imdct_256 , ctx - > tmp_output + 256 , x2 , ctx - > tmp_imdct ) ;
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o_ptr = ctx - > output [ chindex ] ;
d_ptr = ctx - > delay [ chindex ] ;
ptr1 = ( FFTComplex * ) ctx - > tmp_output ;
ptr2 = ( FFTComplex * ) ctx - > tmp_output + 256 ;
w = ctx - > window ;
for ( k = 0 ; k < N / 8 ; k + + )
{
o_ptr [ 2 * k ] = - ptr1 [ k ] . im * w [ 2 * k ] + d_ptr [ 2 * k ] + 384.0 ;
o_ptr [ 2 * k + 1 ] = ptr1 [ N / 8 - k - 1 ] . re * w [ 2 * k + 1 ] + 384.0 ;
o_ptr [ N / 4 + 2 * k ] = - ptr1 [ k ] . re * w [ N / 4 + 2 * k ] + d_ptr [ N / 4 + 2 * k ] + 384.0 ;
o_ptr [ N / 4 + 2 * k + 1 ] = ptr1 [ N / 8 - k - 1 ] . im * w [ N / 4 + 2 * k + 1 ] + d_ptr [ N / 4 + 2 * k + 1 ] + 384.0 ;
d_ptr [ 2 * k ] = ptr2 [ k ] . re * w [ k / 2 - 2 * k - 1 ] ;
d_ptr [ 2 * k + 1 ] = - ptr2 [ N / 8 - k - 1 ] . im * w [ N / 2 - 2 * k - 2 ] ;
d_ptr [ N / 4 + 2 * k ] = ptr2 [ k ] . im * w [ N / 4 - 2 * k - 1 ] ;
d_ptr [ N / 4 + 2 * k + 1 ] = - ptr2 [ N / 8 - k - 1 ] . re * w [ N / 4 - 2 * k - 2 ] ;
}
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}
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/* This function performs the imdct on 512 sample transform
* coefficients .
*/
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static void do_imdct_512 ( AC3DecodeContext * ctx , int chindex )
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{
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float * ptr ;
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ctx - > imdct_512 . fft . imdct_calc ( & ctx - > imdct_512 , ctx - > tmp_output ,
ctx - > transform_coeffs [ chindex ] , ctx - > tmp_imdct ) ;
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ptr = ctx - > output [ chindex ] ;
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ctx - > dsp . vector_fmul_add_add ( ptr , ctx - > tmp_output , ctx - > window , ctx - > delay [ chindex ] , 384 , BLOCK_SIZE , 1 ) ;
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ptr = ctx - > delay [ chindex ] ;
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ctx - > dsp . vector_fmul_reverse ( ptr , ctx - > tmp_output + 256 , ctx - > window , BLOCK_SIZE ) ;
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}
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/* IMDCT Transform. */
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static inline void do_imdct ( AC3DecodeContext * ctx )
{
int i ;
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if ( ctx - > blkoutput & AC3_OUTPUT_LFEON ) {
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do_imdct_512 ( ctx , 0 ) ;
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}
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for ( i = 0 ; i < ctx - > nfchans ; i + + ) {
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if ( ( ctx - > blksw > > i ) & 1 )
do_imdct_256 ( ctx , i + 1 ) ;
else
do_imdct_512 ( ctx , i + 1 ) ;
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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 )
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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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uint8_t * dexps ;
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int mstrcplco , cplcoexp , cplcomant ;
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int dynrng , chbwcod , ngrps , cplabsexp , skipl ;
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ctx - > blksw = 0 ;
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for ( i = 0 ; i < nfchans ; i + + ) /*block switch flag */
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ctx - > blksw | = get_bits1 ( gb ) < < i ;
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ctx - > dithflag = 0 ;
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for ( i = 0 ; i < nfchans ; i + + ) /* dithering flag */
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ctx - > dithflag | = get_bits1 ( gb ) < < i ;
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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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}
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if ( acmod = = 0x00 & & get_bits1 ( gb ) ) { /* dynamic range 1+1 mode */
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dynrng = get_sbits ( gb , 8 ) ;
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ctx - > dynrng2 = ( ( ( ( dynrng & 0x1f ) | 0x20 ) < < 13 ) * scale_factors [ 3 - ( dynrng > > 5 ) ] ) ;
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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 ;
ctx - > chincpl = 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 | = get_bits1 ( gb ) < < i ;
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if ( acmod = = 0x02 )
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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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if ( ctx - > cplinu ) {
ctx - > cplcoe = 0 ;
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for ( i = 0 ; i < nfchans ; i + + )
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if ( ( ctx - > chincpl ) > > i & 1 )
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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 = = 0x02 & & 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 = = 0x02 ) { /* rematrixing */
ctx - > rematstr = get_bits1 ( gb ) ;
if ( ctx - > rematstr ) {
ctx - > rematflg = 0 ;
if ( ! ( ctx - > cplinu ) | | ctx - > cplbegf > 2 )
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for ( rbnd = 0 ; rbnd < 4 ; rbnd + + )
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ctx - > rematflg | = get_bits1 ( gb ) < < rbnd ;
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 | = get_bits1 ( gb ) < < rbnd ;
if ( ctx - > cplbegf = = 0 & & ctx - > cplinu )
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for ( rbnd = 0 ; rbnd < 2 ; rbnd + + )
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ctx - > rematflg | = get_bits1 ( gb ) < < rbnd ;
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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 ) & 1 )
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 ) ) ;
if ( decode_exponents ( gb , ctx - > cplexpstr , ngrps , cplabsexp , ctx - > dcplexps + ctx - > cplstrtmant ) ) {
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av_log ( NULL , AV_LOG_ERROR , " error decoding coupling exponents \n " ) ;
return - 1 ;
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}
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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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if ( decode_exponents ( gb , ctx - > chexpstr [ i ] , ngrps , dexps [ 0 ] , dexps + 1 ) ) {
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av_log ( NULL , AV_LOG_ERROR , " error decoding channel %d exponents \n " , i ) ;
return - 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 ) ;
if ( decode_exponents ( gb , ctx - > lfeexpstr , 2 , ctx - > dlfeexps [ 0 ] , ctx - > dlfeexps + 1 ) ) {
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av_log ( NULL , AV_LOG_ERROR , " error decoding lfe exponents \n " ) ;
return - 1 ;
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}
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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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if ( bit_alloc_flags ) {
if ( is_snr_offsets_zero ( ctx ) ) {
memset ( ctx - > cplbap , 0 , sizeof ( ctx - > cplbap ) ) ;
memset ( ctx - > lfebap , 0 , sizeof ( ctx - > lfebap ) ) ;
for ( i = 0 ; i < nfchans ; i + + )
memset ( ctx - > bap [ i ] , 0 , sizeof ( ctx - > bap [ i ] ) ) ;
} else {
if ( ctx - > chincpl & & ( bit_alloc_flags & 64 ) )
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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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 - > rematflg )
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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 ;
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int frame_start ;
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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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//Synchronize the frame.
frame_start = ac3_synchronize ( buf , buf_size ) ;
if ( frame_start = = - 1 ) {
av_log ( avctx , AV_LOG_ERROR , " frame is not synchronized \n " ) ;
* data_size = 0 ;
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return buf_size ;
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}
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//Initialize the GetBitContext with the start of valid AC3 Frame.
init_get_bits ( & ( ctx - > gb ) , buf + frame_start , ( buf_size - frame_start ) * 8 ) ;
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//Parse the syncinfo.
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//If 'fscod' or 'bsid' is not valid the decoder shall mute as per the standard.
if ( ! ac3_parse_sync_info ( ctx ) ) {
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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//Parse the BSI.
//If 'bsid' is not valid decoder shall not decode the audio as per the standard.
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ac3_parse_bsi ( ctx ) ;
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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 ) ) {
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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 ;
}
AVCodec lgpl_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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} ;