RepoMirrors/ffmpeg
1
0
Fork 0
mirror of https://git.ffmpeg.org/ffmpeg.git synced 2024-12-22 07:20:45 +00:00
Code Issues Projects Releases Wiki Activity

Small simplifications to subband coefficient handling and use av_random().

Browse Source 
Patch by Ian Braithwaite ian .. braithwaite ... dk

Originally committed as revision 8456 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Ian Braithwaite 2007-03-20 18:08:51 +00:00 committed by Benjamin Larsson
parent 0ec4bc6a27
commit 058ee0cf95
1 changed files with 20 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
libavcodec/cook.c
View File

@ -52,6 +52,7 @@
#include "dsputil.h"
#include "common.h"
#include "bytestream.h"
#include "random.h"
#include "cookdata.h"
@ -87,7 +88,7 @@ typedef struct {
int bits_per_subpacket;
int cookversion;
/* states */
int random_state;
AVRandomState random_state;
/* transform data */
MDCTContext mdct_ctx;
@ -373,22 +374,6 @@ static void decode_envelope(COOKContext *q, int* quant_index_table) {
}
}
/**
* Create the quant value table.
*
* @param q pointer to the COOKContext
* @param quant_value_table pointer to the array
*/
static void inline dequant_envelope(COOKContext *q, int* quant_index_table,
float* quant_value_table){
int i;
for(i=0 ; i < q->total_subbands ; i++){
quant_value_table[i] = q->rootpow2tab[quant_index_table[i]+63];
}
}
/**
* Calculate the category and category_index vector.
*
@ -536,33 +521,28 @@ static void inline expand_category(COOKContext *q, int* category,
*
* @param q pointer to the COOKContext
* @param index index
* @param band current subband
* @param quant_value_table pointer to the array
* @param quant_index quantisation index
* @param subband_coef_index array of indexes to quant_centroid_tab
* @param subband_coef_sign signs of coefficients
* @param mlt_buffer pointer to the mlt buffer
* @param mlt_p pointer into the mlt buffer
*/
static void scalar_dequant(COOKContext *q, int index, int band,
float* quant_value_table, int* subband_coef_index,
int* subband_coef_sign, float* mlt_buffer){
static void scalar_dequant(COOKContext *q, int index, int quant_index,
int* subband_coef_index, int* subband_coef_sign,
float* mlt_p){
int i;
float f1;
for(i=0 ; i<SUBBAND_SIZE ; i++) {
if (subband_coef_index[i]) {
if (subband_coef_sign[i]) {
f1 = -quant_centroid_tab[index][subband_coef_index[i]];
} else {
f1 = quant_centroid_tab[index][subband_coef_index[i]];
}
f1 = quant_centroid_tab[index][subband_coef_index[i]];
if (subband_coef_sign[i]) f1 = -f1;
} else {
/* noise coding if subband_coef_index[i] == 0 */
q->random_state = q->random_state * 214013 + 2531011; //typical RNG numbers
f1 = randsign[(q->random_state/0x1000000)&1] * dither_tab[index]; //>>31
f1 = dither_tab[index];
if (av_random(&q->random_state) < 0x80000000) f1 = -f1;
}
mlt_buffer[band*20+ i] = f1 * quant_value_table[band];
mlt_p[i] = f1 * q->rootpow2tab[quant_index+63];
}
}
/**
@ -618,13 +598,13 @@ static int unpack_SQVH(COOKContext *q, int category, int* subband_coef_index,
*
* @param q pointer to the COOKContext
* @param category pointer to the category array
* @param quant_value_table pointer to the array
* @param quant_index_table pointer to the array
* @param mlt_buffer pointer to mlt coefficients
*/
static void decode_vectors(COOKContext* q, int* category,
float* quant_value_table, float* mlt_buffer){
int *quant_index_table, float* mlt_buffer){
/* A zero in this table means that the subband coefficient is
random noise coded. */
int subband_coef_index[SUBBAND_SIZE];
@ -646,8 +626,9 @@ static void decode_vectors(COOKContext* q, int* category,
memset(subband_coef_index, 0, sizeof(subband_coef_index));
memset(subband_coef_sign, 0, sizeof(subband_coef_sign));
}
scalar_dequant(q, index, band, quant_value_table, subband_coef_index,
subband_coef_sign, mlt_buffer);
scalar_dequant(q, index, quant_index_table[band],
subband_coef_index, subband_coef_sign,
&mlt_buffer[band * 20]);
}
if(q->total_subbands*SUBBAND_SIZE >= q->samples_per_channel){
@ -667,20 +648,17 @@ static void decode_vectors(COOKContext* q, int* category,
static void mono_decode(COOKContext *q, float* mlt_buffer) {
int category_index[128];
float quant_value_table[102];
int quant_index_table[102];
int category[128];
memset(&category, 0, 128*sizeof(int));
memset(&quant_value_table, 0, 102*sizeof(int));
memset(&category_index, 0, 128*sizeof(int));
decode_envelope(q, quant_index_table);
q->num_vectors = get_bits(&q->gb,q->log2_numvector_size);
dequant_envelope(q, quant_index_table, quant_value_table);
categorize(q, quant_index_table, category, category_index);
expand_category(q, category, category_index);
decode_vectors(q, category, quant_value_table, mlt_buffer);
decode_vectors(q, category, quant_index_table, mlt_buffer);
}
@ -1035,8 +1013,8 @@ static int cook_decode_init(AVCodecContext *avctx)
q->nb_channels = avctx->channels;
q->bit_rate = avctx->bit_rate;
/* Initialize state. */
q->random_state = 1;
/* Initialize RNG. */
av_init_random(1, &q->random_state);
/* Initialize extradata related variables. */
q->samples_per_channel = q->samples_per_frame / q->nb_channels;