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ffmpeg-mt
Commit 717ec2cd authored by jbr's avatar jbr
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use floating-point mantissa dequantization tables 

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9888 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b
parent cdc8b191
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Showing with 80 additions and 121 deletions
libavcodec/ac3dec.c
View file @ 717ec2cd
...@@ -52,22 +52,22 @@ static float scale_factors[25]; ...@@ -52,22 +52,22 @@ static float scale_factors[25];
/** table for grouping exponents */ /** table for grouping exponents */
static uint8_t exp_ungroup_tbl[128][3]; static uint8_t exp_ungroup_tbl[128][3];
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]; /** tables for ungrouping mantissas */
static int16_t l5_quantizers_2[128]; static float b1_mantissas[32][3];
static int16_t l5_quantizers_3[128]; static float b2_mantissas[128][3];
static float b3_mantissas[8];
static float b4_mantissas[128][2];
static float b5_mantissas[16];
static int16_t l7_quantizers[7]; /**
* Quantization table: levels for symmetric. bits for asymmetric.
static int16_t l11_quantizers_1[128]; * reference: Table 7.18 Mapping of bap to Quantizer
static int16_t l11_quantizers_2[128]; */
static const uint8_t qntztab[16] = {
static int16_t l15_quantizers[15]; 0, 3, 5, 7, 11, 15,
5, 6, 7, 8, 9, 10, 11, 12, 14, 16
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 */ /* Adjustmens in dB gain */
#define LEVEL_MINUS_3DB 0.7071067811865476 #define LEVEL_MINUS_3DB 0.7071067811865476
...@@ -193,58 +193,10 @@ static void ac3_window_init(float *window) ...@@ -193,58 +193,10 @@ static void ac3_window_init(float *window)
window[i] = sqrt(local_window[i] / sum); window[i] = sqrt(local_window[i] / sum);
} }
/* static inline float
* Generate quantizer tables. symmetric_dequant(int code, int levels)
*/
static void generate_quantizers_table(int16_t quantizers[], int level, int length)
{ {
int i; return (code - (levels >> 1)) * (2.0f / levels);
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;
for (i = length1 * length2; i < size; i++)
quantizers[i] = 0;
} }
/* /*
...@@ -254,31 +206,38 @@ static void ac3_tables_init(void) ...@@ -254,31 +206,38 @@ static void ac3_tables_init(void)
{ {
int i; int i;
/* Quantizer ungrouping tables. */ /* generate grouped mantissa tables
// for level-3 quantizers reference: Section 7.3.5 Ungrouping of Mantissas */
generate_quantizers_table_1(l3_quantizers_1, 3, 3, 9, 32); for(i=0; i<32; i++) {
generate_quantizers_table_2(l3_quantizers_2, 3, 9, 3, 32); /* bap=1 mantissas */
generate_quantizers_table_3(l3_quantizers_3, 3, 9, 3, 32); b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
//for level-5 quantizers b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
generate_quantizers_table_1(l5_quantizers_1, 5, 5, 25, 128); }
generate_quantizers_table_2(l5_quantizers_2, 5, 25, 5, 128); for(i=0; i<128; i++) {
generate_quantizers_table_3(l5_quantizers_3, 5, 25, 5, 128); /* bap=2 mantissas */
b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5);
//for level-7 quantizers b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
generate_quantizers_table(l7_quantizers, 7, 7); b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
//for level-4 quantizers /* bap=4 mantissas */
generate_quantizers_table_2(l11_quantizers_1, 11, 11, 11, 128); b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
generate_quantizers_table_3(l11_quantizers_2, 11, 11, 11, 128); b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
}
//for level-15 quantizers /* generate ungrouped mantissa tables
generate_quantizers_table(l15_quantizers, 15, 15); reference: Tables 7.21 and 7.23 */
/* End Quantizer ungrouping tables. */ for(i=0; i<7; i++) {
/* bap=3 mantissas */
b3_mantissas[i] = symmetric_dequant(i, 7);
}
for(i=0; i<15; i++) {
/* bap=5 mantissas */
b5_mantissas[i] = symmetric_dequant(i, 15);
}
//generate scale factors //generate scale factors
for (i = 0; i < 25; i++) for (i = 0; i < 25; i++)
scale_factors[i] = pow(2.0, -(i + 15)); scale_factors[i] = pow(2.0, -i);
/* generate exponent tables /* generate exponent tables
reference: Section 7.1.3 Exponent Decoding */ reference: Section 7.1.3 Exponent Decoding */
...@@ -440,7 +399,7 @@ static void uncouple_channels(AC3DecodeContext *ctx) ...@@ -440,7 +399,7 @@ static void uncouple_channels(AC3DecodeContext *ctx)
for(j=0; j<12; j++) { for(j=0; j<12; j++) {
for(ch=1; ch<=ctx->nfchans; ch++) { for(ch=1; ch<=ctx->nfchans; ch++) {
if(ctx->chincpl[ch-1]) if(ctx->chincpl[ch-1])
ctx->transform_coeffs[ch][i] = ctx->transform_coeffs_cpl[i] * ctx->cplco[ch-1][bnd]; ctx->transform_coeffs[ch][i] = ctx->transform_coeffs_cpl[i] * ctx->cplco[ch-1][bnd] * 8.0f;
} }
i++; i++;
} }
...@@ -449,12 +408,12 @@ static void uncouple_channels(AC3DecodeContext *ctx) ...@@ -449,12 +408,12 @@ static void uncouple_channels(AC3DecodeContext *ctx)
} }
typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */ typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
int16_t l3_quantizers[3]; float b1_mant[3];
int16_t l5_quantizers[3]; float b2_mant[3];
int16_t l11_quantizers[2]; float b4_mant[2];
int l3ptr; int b1ptr;
int l5ptr; int b2ptr;
int l11ptr; int b4ptr;
} mant_groups; } mant_groups;
/* Get the transform coefficients for particular channel */ /* Get the transform coefficients for particular channel */
...@@ -491,51 +450,51 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro ...@@ -491,51 +450,51 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
tbap = bap[i]; tbap = bap[i];
switch (tbap) { switch (tbap) {
case 0: case 0:
coeffs[i] = (av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB; coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB) / 32768.0f;
break; break;
case 1: case 1:
if (m->l3ptr > 2) { if(m->b1ptr > 2) {
gcode = get_bits(gb, 5); gcode = get_bits(gb, 5);
m->l3_quantizers[0] = l3_quantizers_1[gcode]; m->b1_mant[0] = b1_mantissas[gcode][0];
m->l3_quantizers[1] = l3_quantizers_2[gcode]; m->b1_mant[1] = b1_mantissas[gcode][1];
m->l3_quantizers[2] = l3_quantizers_3[gcode]; m->b1_mant[2] = b1_mantissas[gcode][2];
m->l3ptr = 0; m->b1ptr = 0;
} }
coeffs[i] = m->l3_quantizers[m->l3ptr++]; coeffs[i] = m->b1_mant[m->b1ptr++];
break; break;
case 2: case 2:
if (m->l5ptr > 2) { if(m->b2ptr > 2) {
gcode = get_bits(gb, 7); gcode = get_bits(gb, 7);
m->l5_quantizers[0] = l5_quantizers_1[gcode]; m->b2_mant[0] = b2_mantissas[gcode][0];
m->l5_quantizers[1] = l5_quantizers_2[gcode]; m->b2_mant[1] = b2_mantissas[gcode][1];
m->l5_quantizers[2] = l5_quantizers_3[gcode]; m->b2_mant[2] = b2_mantissas[gcode][2];
m->l5ptr = 0; m->b2ptr = 0;
} }
coeffs[i] = m->l5_quantizers[m->l5ptr++]; coeffs[i] = m->b2_mant[m->b2ptr++];
break; break;
case 3: case 3:
coeffs[i] = l7_quantizers[get_bits(gb, 3)]; coeffs[i] = b3_mantissas[get_bits(gb, 3)];
break; break;
case 4: case 4:
if (m->l11ptr > 1) { if(m->b4ptr > 1) {
gcode = get_bits(gb, 7); gcode = get_bits(gb, 7);
m->l11_quantizers[0] = l11_quantizers_1[gcode]; m->b4_mant[0] = b4_mantissas[gcode][0];
m->l11_quantizers[1] = l11_quantizers_2[gcode]; m->b4_mant[1] = b4_mantissas[gcode][1];
m->l11ptr = 0; m->b4ptr = 0;
} }
coeffs[i] = m->l11_quantizers[m->l11ptr++]; coeffs[i] = m->b4_mant[m->b4ptr++];
break; break;
case 5: case 5:
coeffs[i] = l15_quantizers[get_bits(gb, 4)]; coeffs[i] = b5_mantissas[get_bits(gb, 4)];
break; break;
default: default:
coeffs[i] = get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap]); coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
break; break;
} }
coeffs[i] *= scale_factors[exps[i]]; coeffs[i] *= scale_factors[exps[i]];
...@@ -587,7 +546,7 @@ static int get_transform_coeffs(AC3DecodeContext * ctx) ...@@ -587,7 +546,7 @@ static int get_transform_coeffs(AC3DecodeContext * ctx)
int got_cplchan = 0; int got_cplchan = 0;
mant_groups m; mant_groups m;
m.l3ptr = m.l5ptr = m.l11ptr = 3; m.b1ptr = m.b2ptr = m.b4ptr = 3;
for (i = 0; i < ctx->nfchans; i++) { for (i = 0; i < ctx->nfchans; i++) {
/* transform coefficients for individual channel */ /* transform coefficients for individual channel */
...@@ -747,7 +706,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk) ...@@ -747,7 +706,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
if (get_bits1(gb)) { /* dynamic range */ if (get_bits1(gb)) { /* dynamic range */
dynrng = get_sbits(gb, 8); dynrng = get_sbits(gb, 8);
ctx->dynrng = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]); ctx->dynrng = (((dynrng & 0x1f) | 0x20) << 13) * pow(2.0, -(18 - (dynrng >> 5)));
} else if(blk == 0) { } else if(blk == 0) {
ctx->dynrng = 1.0; ctx->dynrng = 1.0;
} }
...@@ -755,7 +714,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk) ...@@ -755,7 +714,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
if(acmod == AC3_ACMOD_DUALMONO) { /* dynamic range 1+1 mode */ if(acmod == AC3_ACMOD_DUALMONO) { /* dynamic range 1+1 mode */
if(get_bits1(gb)) { if(get_bits1(gb)) {
dynrng = get_sbits(gb, 8); dynrng = get_sbits(gb, 8);
ctx->dynrng2 = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]); ctx->dynrng2 = (((dynrng & 0x1f) | 0x20) << 13) * pow(2.0, -(18 - (dynrng >> 5)));
} else if(blk == 0) { } else if(blk == 0) {
ctx->dynrng2 = 1.0; ctx->dynrng2 = 1.0;
} }
...@@ -807,10 +766,10 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk) ...@@ -807,10 +766,10 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
cplcoexp = get_bits(gb, 4); cplcoexp = get_bits(gb, 4);
cplcomant = get_bits(gb, 4); cplcomant = get_bits(gb, 4);
if (cplcoexp == 15) if (cplcoexp == 15)
cplcomant <<= 14; ctx->cplco[i][bnd] = cplcomant / 16.0f;
else else
cplcomant = (cplcomant | 0x10) << 13; ctx->cplco[i][bnd] = (cplcomant + 16.0f) / 32.0f;
ctx->cplco[i][bnd] = cplcomant * scale_factors[cplcoexp + mstrcplco]; ctx->cplco[i][bnd] *= scale_factors[cplcoexp + mstrcplco];
} }
} }
......
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