use floating-point mantissa dequantization tables
Originally committed as revision 9888 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles
parent
04ac5cada1
commit
5aefe3ebef
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@ -52,22 +52,22 @@ static float scale_factors[25];
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/** table for grouping exponents */
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static uint8_t exp_ungroup_tbl[128][3];
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static int16_t l3_quantizers_1[32];
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static int16_t l3_quantizers_2[32];
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static int16_t l3_quantizers_3[32];
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static int16_t l5_quantizers_1[128];
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static int16_t l5_quantizers_2[128];
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static int16_t l5_quantizers_3[128];
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/** tables for ungrouping mantissas */
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static float b1_mantissas[32][3];
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static float b2_mantissas[128][3];
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static float b3_mantissas[8];
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static float b4_mantissas[128][2];
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static float b5_mantissas[16];
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static int16_t l7_quantizers[7];
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static int16_t l11_quantizers_1[128];
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static int16_t l11_quantizers_2[128];
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static int16_t l15_quantizers[15];
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static const uint8_t qntztab[16] = { 0, 5, 7, 3, 7, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 };
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/**
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* Quantization table: levels for symmetric. bits for asymmetric.
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* reference: Table 7.18 Mapping of bap to Quantizer
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*/
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static const uint8_t qntztab[16] = {
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0, 3, 5, 7, 11, 15,
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5, 6, 7, 8, 9, 10, 11, 12, 14, 16
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};
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/* Adjustmens in dB gain */
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#define LEVEL_MINUS_3DB 0.7071067811865476
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@ -193,58 +193,10 @@ static void ac3_window_init(float *window)
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window[i] = sqrt(local_window[i] / sum);
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}
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/*
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* Generate quantizer tables.
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*/
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static void generate_quantizers_table(int16_t quantizers[], int level, int length)
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static inline float
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symmetric_dequant(int code, int levels)
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{
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int i;
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for (i = 0; i < length; i++)
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quantizers[i] = ((2 * i - level + 1) << 15) / level;
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}
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static void generate_quantizers_table_1(int16_t quantizers[], int level, int length1, int length2, int size)
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{
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int i, j;
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int16_t v;
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for (i = 0; i < length1; i++) {
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v = ((2 * i - level + 1) << 15) / level;
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for (j = 0; j < length2; j++)
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quantizers[i * length2 + j] = v;
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}
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for (i = length1 * length2; i < size; i++)
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quantizers[i] = 0;
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}
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static void generate_quantizers_table_2(int16_t quantizers[], int level, int length1, int length2, int size)
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{
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int i, j;
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int16_t v;
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for (i = 0; i < length1; i++) {
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v = ((2 * (i % level) - level + 1) << 15) / level;
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for (j = 0; j < length2; j++)
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quantizers[i * length2 + j] = v;
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}
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for (i = length1 * length2; i < size; i++)
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quantizers[i] = 0;
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}
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static void generate_quantizers_table_3(int16_t quantizers[], int level, int length1, int length2, int size)
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{
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int i, j;
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for (i = 0; i < length1; i++)
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for (j = 0; j < length2; j++)
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quantizers[i * length2 + j] = ((2 * (j % level) - level + 1) << 15) / level;
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for (i = length1 * length2; i < size; i++)
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quantizers[i] = 0;
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return (code - (levels >> 1)) * (2.0f / levels);
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}
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/*
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@ -254,31 +206,38 @@ static void ac3_tables_init(void)
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{
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int i;
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/* Quantizer ungrouping tables. */
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// for level-3 quantizers
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generate_quantizers_table_1(l3_quantizers_1, 3, 3, 9, 32);
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generate_quantizers_table_2(l3_quantizers_2, 3, 9, 3, 32);
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generate_quantizers_table_3(l3_quantizers_3, 3, 9, 3, 32);
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/* generate grouped mantissa tables
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reference: Section 7.3.5 Ungrouping of Mantissas */
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for(i=0; i<32; i++) {
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/* bap=1 mantissas */
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b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
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b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
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b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
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}
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for(i=0; i<128; i++) {
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/* bap=2 mantissas */
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b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5);
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b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
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b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
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//for level-5 quantizers
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generate_quantizers_table_1(l5_quantizers_1, 5, 5, 25, 128);
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generate_quantizers_table_2(l5_quantizers_2, 5, 25, 5, 128);
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generate_quantizers_table_3(l5_quantizers_3, 5, 25, 5, 128);
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//for level-7 quantizers
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generate_quantizers_table(l7_quantizers, 7, 7);
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//for level-4 quantizers
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generate_quantizers_table_2(l11_quantizers_1, 11, 11, 11, 128);
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generate_quantizers_table_3(l11_quantizers_2, 11, 11, 11, 128);
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//for level-15 quantizers
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generate_quantizers_table(l15_quantizers, 15, 15);
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/* End Quantizer ungrouping tables. */
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/* bap=4 mantissas */
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b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
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b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
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}
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/* generate ungrouped mantissa tables
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reference: Tables 7.21 and 7.23 */
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for(i=0; i<7; i++) {
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/* bap=3 mantissas */
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b3_mantissas[i] = symmetric_dequant(i, 7);
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}
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for(i=0; i<15; i++) {
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/* bap=5 mantissas */
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b5_mantissas[i] = symmetric_dequant(i, 15);
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}
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//generate scale factors
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for (i = 0; i < 25; i++)
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scale_factors[i] = pow(2.0, -(i + 15));
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scale_factors[i] = pow(2.0, -i);
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/* generate exponent tables
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reference: Section 7.1.3 Exponent Decoding */
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@ -440,7 +399,7 @@ static void uncouple_channels(AC3DecodeContext *ctx)
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for(j=0; j<12; j++) {
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for(ch=1; ch<=ctx->nfchans; ch++) {
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if(ctx->chincpl[ch-1])
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ctx->transform_coeffs[ch][i] = ctx->transform_coeffs_cpl[i] * ctx->cplco[ch-1][bnd];
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ctx->transform_coeffs[ch][i] = ctx->transform_coeffs_cpl[i] * ctx->cplco[ch-1][bnd] * 8.0f;
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}
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i++;
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}
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@ -449,12 +408,12 @@ static void uncouple_channels(AC3DecodeContext *ctx)
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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];
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int16_t l5_quantizers[3];
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int16_t l11_quantizers[2];
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int l3ptr;
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int l5ptr;
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int l11ptr;
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float b1_mant[3];
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float b2_mant[3];
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float b4_mant[2];
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int b1ptr;
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int b2ptr;
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int b4ptr;
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} mant_groups;
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/* Get the transform coefficients for particular channel */
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@ -491,51 +450,51 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
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tbap = bap[i];
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switch (tbap) {
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case 0:
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coeffs[i] = (av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB;
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coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB) / 32768.0f;
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break;
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case 1:
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if (m->l3ptr > 2) {
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if(m->b1ptr > 2) {
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gcode = get_bits(gb, 5);
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m->l3_quantizers[0] = l3_quantizers_1[gcode];
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m->l3_quantizers[1] = l3_quantizers_2[gcode];
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m->l3_quantizers[2] = l3_quantizers_3[gcode];
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m->l3ptr = 0;
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m->b1_mant[0] = b1_mantissas[gcode][0];
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m->b1_mant[1] = b1_mantissas[gcode][1];
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m->b1_mant[2] = b1_mantissas[gcode][2];
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m->b1ptr = 0;
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}
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coeffs[i] = m->l3_quantizers[m->l3ptr++];
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coeffs[i] = m->b1_mant[m->b1ptr++];
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break;
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case 2:
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if (m->l5ptr > 2) {
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if(m->b2ptr > 2) {
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gcode = get_bits(gb, 7);
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m->l5_quantizers[0] = l5_quantizers_1[gcode];
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m->l5_quantizers[1] = l5_quantizers_2[gcode];
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m->l5_quantizers[2] = l5_quantizers_3[gcode];
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m->l5ptr = 0;
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m->b2_mant[0] = b2_mantissas[gcode][0];
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m->b2_mant[1] = b2_mantissas[gcode][1];
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m->b2_mant[2] = b2_mantissas[gcode][2];
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m->b2ptr = 0;
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}
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coeffs[i] = m->l5_quantizers[m->l5ptr++];
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coeffs[i] = m->b2_mant[m->b2ptr++];
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break;
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case 3:
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coeffs[i] = l7_quantizers[get_bits(gb, 3)];
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coeffs[i] = b3_mantissas[get_bits(gb, 3)];
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break;
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case 4:
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if (m->l11ptr > 1) {
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if(m->b4ptr > 1) {
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gcode = get_bits(gb, 7);
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m->l11_quantizers[0] = l11_quantizers_1[gcode];
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m->l11_quantizers[1] = l11_quantizers_2[gcode];
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m->l11ptr = 0;
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m->b4_mant[0] = b4_mantissas[gcode][0];
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m->b4_mant[1] = b4_mantissas[gcode][1];
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m->b4ptr = 0;
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}
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coeffs[i] = m->l11_quantizers[m->l11ptr++];
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coeffs[i] = m->b4_mant[m->b4ptr++];
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break;
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case 5:
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coeffs[i] = l15_quantizers[get_bits(gb, 4)];
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coeffs[i] = b5_mantissas[get_bits(gb, 4)];
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break;
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default:
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coeffs[i] = get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap]);
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coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
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break;
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}
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coeffs[i] *= scale_factors[exps[i]];
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@ -587,7 +546,7 @@ static int get_transform_coeffs(AC3DecodeContext * ctx)
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int got_cplchan = 0;
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mant_groups m;
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m.l3ptr = m.l5ptr = m.l11ptr = 3;
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m.b1ptr = m.b2ptr = m.b4ptr = 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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@ -747,7 +706,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
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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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ctx->dynrng = (((dynrng & 0x1f) | 0x20) << 13) * pow(2.0, -(18 - (dynrng >> 5)));
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} else if(blk == 0) {
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ctx->dynrng = 1.0;
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}
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@ -755,7 +714,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
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if(acmod == AC3_ACMOD_DUALMONO) { /* dynamic range 1+1 mode */
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if(get_bits1(gb)) {
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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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ctx->dynrng2 = (((dynrng & 0x1f) | 0x20) << 13) * pow(2.0, -(18 - (dynrng >> 5)));
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} else if(blk == 0) {
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ctx->dynrng2 = 1.0;
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}
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@ -807,10 +766,10 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
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cplcoexp = get_bits(gb, 4);
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cplcomant = get_bits(gb, 4);
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if (cplcoexp == 15)
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cplcomant <<= 14;
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ctx->cplco[i][bnd] = cplcomant / 16.0f;
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else
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cplcomant = (cplcomant | 0x10) << 13;
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ctx->cplco[i][bnd] = cplcomant * scale_factors[cplcoexp + mstrcplco];
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ctx->cplco[i][bnd] = (cplcomant + 16.0f) / 32.0f;
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ctx->cplco[i][bnd] *= scale_factors[cplcoexp + mstrcplco];
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}
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}
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