mirror of https://git.ffmpeg.org/ffmpeg.git
split out coupling coefficient reconstruction into a separate function
Originally committed as revision 9882 to svn://svn.ffmpeg.org/ffmpeg/trunk
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@ -148,6 +148,7 @@ typedef struct {
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uint8_t bap[5][256]; //fbw channel bit allocation pointers
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uint8_t bap[5][256]; //fbw channel bit allocation pointers
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uint8_t lfebap[256]; //lfe channel bit allocation pointers
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uint8_t lfebap[256]; //lfe channel bit allocation pointers
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float transform_coeffs_cpl[256];
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DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); //transform coefficients
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DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); //transform coefficients
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/* For IMDCT. */
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/* For IMDCT. */
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@ -421,6 +422,31 @@ static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
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}
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}
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}
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}
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/**
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* Generates transform coefficients for each coupled channel in the coupling
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* range using the coupling coefficients and coupling coordinates.
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* reference: Section 7.4.3 Coupling Coordinate Format
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*/
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static void uncouple_channels(AC3DecodeContext *ctx)
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{
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int i, j, ch, bnd, subbnd;
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subbnd = -1;
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i = ctx->cplstrtmant;
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for(bnd=0; bnd<ctx->ncplbnd; bnd++) {
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do {
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subbnd++;
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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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}
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i++;
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}
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} while((ctx->cplbndstrc >> subbnd) & 1);
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}
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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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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 l3_quantizers[3];
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int16_t l5_quantizers[3];
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int16_t l5_quantizers[3];
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@ -438,40 +464,18 @@ typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantizati
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static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
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static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
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{
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{
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GetBitContext *gb = &ctx->gb;
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GetBitContext *gb = &ctx->gb;
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int ch, start, end, cplbndstrc, bnd, gcode, tbap;
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int start, gcode, tbap;
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float cplcos[5], cplcoeff;
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float cplcoeff;
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uint8_t *exps = ctx->dcplexps;
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uint8_t *exps = ctx->dcplexps;
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uint8_t *bap = ctx->cplbap;
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uint8_t *bap = ctx->cplbap;
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cplbndstrc = ctx->cplbndstrc;
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start = ctx->cplstrtmant;
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start = ctx->cplstrtmant;
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bnd = 0;
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while (start < ctx->cplendmant) {
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while (start < ctx->cplendmant) {
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end = start + 12;
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while (cplbndstrc & 1) {
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end += 12;
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cplbndstrc >>= 1;
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}
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cplbndstrc >>= 1;
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for (ch = 0; ch < ctx->nfchans; ch++)
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cplcos[ch] = ctx->cplco[ch][bnd];
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bnd++;
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while (start < end) {
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tbap = bap[start];
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tbap = bap[start];
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switch(tbap) {
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switch(tbap) {
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case 0:
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case 0:
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for (ch = 0; ch < ctx->nfchans; ch++)
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cplcoeff = (av_random(&ctx->dith_state) & 0xFFFF);
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if (ctx->chincpl[ch]) {
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break;
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if (ctx->dithflag[ch]) {
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cplcoeff = (av_random(&ctx->dith_state) & 0xFFFF) * scale_factors[exps[start]];
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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;
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case 1:
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case 1:
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if (m->l3ptr > 2) {
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if (m->l3ptr > 2) {
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gcode = get_bits(gb, 5);
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gcode = get_bits(gb, 5);
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@ -480,7 +484,7 @@ static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
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m->l3_quantizers[2] = l3_quantizers_3[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->l3ptr = 0;
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}
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}
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cplcoeff = m->l3_quantizers[m->l3ptr++] * scale_factors[exps[start]];
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cplcoeff = m->l3_quantizers[m->l3ptr++];
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break;
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break;
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case 2:
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case 2:
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@ -491,11 +495,11 @@ static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
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m->l5_quantizers[2] = l5_quantizers_3[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->l5ptr = 0;
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}
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}
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cplcoeff = m->l5_quantizers[m->l5ptr++] * scale_factors[exps[start]];
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cplcoeff = m->l5_quantizers[m->l5ptr++];
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break;
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break;
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case 3:
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case 3:
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cplcoeff = l7_quantizers[get_bits(gb, 3)] * scale_factors[exps[start]];
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cplcoeff = l7_quantizers[get_bits(gb, 3)];
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break;
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break;
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case 4:
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case 4:
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@ -505,22 +509,19 @@ static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
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m->l11_quantizers[1] = l11_quantizers_2[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->l11ptr = 0;
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}
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}
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cplcoeff = m->l11_quantizers[m->l11ptr++] * scale_factors[exps[start]];
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cplcoeff = m->l11_quantizers[m->l11ptr++];
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break;
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break;
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case 5:
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case 5:
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cplcoeff = l15_quantizers[get_bits(gb, 4)] * scale_factors[exps[start]];
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cplcoeff = l15_quantizers[get_bits(gb, 4)];
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break;
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break;
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default:
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default:
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cplcoeff = (get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap])) * scale_factors[exps[start]];
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cplcoeff = get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap]);
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}
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}
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for (ch = 0; ch < ctx->nfchans; ch++)
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ctx->transform_coeffs_cpl[start] = cplcoeff * scale_factors[exps[start]];
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if (ctx->chincpl[ch])
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ctx->transform_coeffs[ch + 1][start] = cplcoeff * cplcos[ch];
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start++;
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start++;
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}
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}
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}
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return 0;
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return 0;
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}
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}
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@ -635,6 +636,7 @@ static int get_transform_coeffs(AC3DecodeContext * ctx)
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av_log(NULL, AV_LOG_ERROR, "error in decoupling channels\n");
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av_log(NULL, AV_LOG_ERROR, "error in decoupling channels\n");
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return -1;
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return -1;
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}
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}
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uncouple_channels(ctx);
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got_cplchan = 1;
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got_cplchan = 1;
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}
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}
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end = ctx->cplendmant;
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end = ctx->cplendmant;
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