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Hardcode the table for ungrouping 3 values in 5 bits. It will be reused by 

the E-AC-3 decoder.

Originally committed as revision 14527 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2008-08-03 21:42:43 +00:00
parent 021b8ae39b
commit 602116df9b
3 changed files with 20 additions and 3 deletions
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6
libavcodec/ac3dec.c
View File

@ -150,9 +150,9 @@ static av_cold void ac3_tables_init(void)
reference: Section 7.3.5 Ungrouping of Mantissas */
for(i=0; i<32; i++) {
/* bap=1 mantissas */
b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
}
for(i=0; i<128; i++) {
/* bap=2 mantissas */

16
libavcodec/ac3dec_data.c
View File

@ -27,6 +27,22 @@
#include "ac3dec_data.h"
#include "ac3.h"
/**
* table used to ungroup 3 values stored in 5 bits.
* used by bap=1 mantissas and GAQ.
* ff_ac3_ungroup_3_in_5_bits_tab[i] = { i/9, (i%9)/3, (i%9)%3 }
*/
const uint8_t ff_ac3_ungroup_3_in_5_bits_tab[32][3] = {
{ 0, 0, 0 }, { 0, 0, 1 }, { 0, 0, 2 }, { 0, 1, 0 },
{ 0, 1, 1 }, { 0, 1, 2 }, { 0, 2, 0 }, { 0, 2, 1 },
{ 0, 2, 2 }, { 1, 0, 0 }, { 1, 0, 1 }, { 1, 0, 2 },
{ 1, 1, 0 }, { 1, 1, 1 }, { 1, 1, 2 }, { 1, 2, 0 },
{ 1, 2, 1 }, { 1, 2, 2 }, { 2, 0, 0 }, { 2, 0, 1 },
{ 2, 0, 2 }, { 2, 1, 0 }, { 2, 1, 1 }, { 2, 1, 2 },
{ 2, 2, 0 }, { 2, 2, 1 }, { 2, 2, 2 }, { 3, 0, 0 },
{ 3, 0, 1 }, { 3, 0, 2 }, { 3, 1, 0 }, { 3, 1, 1 }
};
const uint8_t ff_eac3_hebap_tab[64] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 8,
8, 8, 9, 9, 9, 10, 10, 10, 10, 11,

1
libavcodec/ac3dec_data.h
View File

@ -24,6 +24,7 @@
#include "libavutil/common.h"
extern const uint8_t ff_ac3_ungroup_3_in_5_bits_tab[32][3];
extern const uint8_t ff_eac3_hebap_tab[64];
extern const uint8_t ff_eac3_bits_vs_hebap[20];
extern const int16_t ff_eac3_gaq_remap_1[12];