static void apply_channel_coupling(AC3EncodeContext *s) { LOCAL_ALIGNED_16(CoefType, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); #if CONFIG_AC3ENC_FLOAT LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); #else int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords; #endif int blk, ch, bnd, i, j; CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}}; int cpl_start, num_cpl_coefs; memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); #if CONFIG_AC3ENC_FLOAT memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); #endif /* align start to 16-byte boundary. align length to multiple of 32. note: coupling start bin % 4 will always be 1 */ cpl_start = s->start_freq[CPL_CH] - 1; num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32); cpl_start = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs; /* calculate coupling channel from fbw channels */ for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start]; if (!block->cpl_in_use) continue; memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef)); for (ch = 1; ch <= s->fbw_channels; ch++) { CoefType *ch_coef = &block->mdct_coef[ch][cpl_start]; if (!block->channel_in_cpl[ch]) continue; for (i = 0; i < num_cpl_coefs; i++) cpl_coef[i] += ch_coef[i]; } /* coefficients must be clipped in order to be encoded */ clip_coefficients(&s->dsp, cpl_coef, num_cpl_coefs); } /* calculate energy in each band in coupling channel and each fbw channel */ /* TODO: possibly use SIMD to speed up energy calculation */ bnd = 0; i = s->start_freq[CPL_CH]; while (i < s->cpl_end_freq) { int band_size = s->cpl_band_sizes[bnd]; for (ch = CPL_CH; ch <= s->fbw_channels; ch++) { for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch])) continue; for (j = 0; j < band_size; j++) { CoefType v = block->mdct_coef[ch][i+j]; MAC_COEF(energy[blk][ch][bnd], v, v); } } } i += band_size; bnd++; } /* calculate coupling coordinates for all blocks for all channels */ for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; if (!block->cpl_in_use) continue; for (ch = 1; ch <= s->fbw_channels; ch++) { if (!block->channel_in_cpl[ch]) continue; for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd], energy[blk][CPL_CH][bnd]); } } } /* determine which blocks to send new coupling coordinates for */ for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL; memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords)); if (block->cpl_in_use) { /* send new coordinates if this is the first block, if previous * block did not use coupling but this block does, the channels * using coupling has changed from the previous block, or the * coordinate difference from the last block for any channel is * greater than a threshold value. */ if (blk == 0 || !block0->cpl_in_use) { for (ch = 1; ch <= s->fbw_channels; ch++) block->new_cpl_coords[ch] = 1; } else { for (ch = 1; ch <= s->fbw_channels; ch++) { if (!block->channel_in_cpl[ch]) continue; if (!block0->channel_in_cpl[ch]) { block->new_cpl_coords[ch] = 1; } else { CoefSumType coord_diff = 0; for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] - cpl_coords[blk ][ch][bnd]); } coord_diff /= s->num_cpl_bands; if (coord_diff > NEW_CPL_COORD_THRESHOLD) block->new_cpl_coords[ch] = 1; } } } } } /* calculate final coupling coordinates, taking into account reusing of coordinates in successive blocks */ for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { blk = 0; while (blk < s->num_blocks) { int av_uninit(blk1); AC3Block *block = &s->blocks[blk]; if (!block->cpl_in_use) { blk++; continue; } for (ch = 1; ch <= s->fbw_channels; ch++) { CoefSumType energy_ch, energy_cpl; if (!block->channel_in_cpl[ch]) continue; energy_cpl = energy[blk][CPL_CH][bnd]; energy_ch = energy[blk][ch][bnd]; blk1 = blk+1; while (!s->blocks[blk1].new_cpl_coords[ch] && blk1 < s->num_blocks) { if (s->blocks[blk1].cpl_in_use) { energy_cpl += energy[blk1][CPL_CH][bnd]; energy_ch += energy[blk1][ch][bnd]; } blk1++; } cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl); } blk = blk1; } } /* calculate exponents/mantissas for coupling coordinates */ for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; if (!block->cpl_in_use) continue; #if CONFIG_AC3ENC_FLOAT s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1], cpl_coords[blk][1], s->fbw_channels * 16); #endif s->ac3dsp.extract_exponents(block->cpl_coord_exp[1], fixed_cpl_coords[blk][1], s->fbw_channels * 16); for (ch = 1; ch <= s->fbw_channels; ch++) { int bnd, min_exp, max_exp, master_exp; if (!block->new_cpl_coords[ch]) continue; /* determine master exponent */ min_exp = max_exp = block->cpl_coord_exp[ch][0]; for (bnd = 1; bnd < s->num_cpl_bands; bnd++) { int exp = block->cpl_coord_exp[ch][bnd]; min_exp = FFMIN(exp, min_exp); max_exp = FFMAX(exp, max_exp); } master_exp = ((max_exp - 15) + 2) / 3; master_exp = FFMAX(master_exp, 0); while (min_exp < master_exp * 3) master_exp--; for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] - master_exp * 3, 0, 15); } block->cpl_master_exp[ch] = master_exp; /* quantize mantissas */ for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { int cpl_exp = block->cpl_coord_exp[ch][bnd]; int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24; if (cpl_exp == 15) cpl_mant >>= 1; else cpl_mant -= 16; block->cpl_coord_mant[ch][bnd] = cpl_mant; } } } if (CONFIG_EAC3_ENCODER && s->eac3) ff_eac3_set_cpl_states(s); }