| /* |
| * AC-3 encoder float/fixed template |
| * Copyright (c) 2000 Fabrice Bellard |
| * Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com> |
| * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> |
| * |
| * This file is part of Libav. |
| * |
| * Libav is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * Libav is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with Libav; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * AC-3 encoder float/fixed template |
| */ |
| |
| #include <stdint.h> |
| |
| #include "ac3enc.h" |
| |
| |
| int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s) |
| { |
| int ch; |
| |
| FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE * |
| sizeof(*s->windowed_samples), alloc_fail); |
| FF_ALLOC_OR_GOTO(s->avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples), |
| alloc_fail); |
| for (ch = 0; ch < s->channels; ch++) { |
| FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch], |
| (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples), |
| alloc_fail); |
| } |
| |
| return 0; |
| alloc_fail: |
| return AVERROR(ENOMEM); |
| } |
| |
| |
| /** |
| * Deinterleave input samples. |
| * Channels are reordered from Libav's default order to AC-3 order. |
| */ |
| void AC3_NAME(deinterleave_input_samples)(AC3EncodeContext *s, |
| const SampleType *samples) |
| { |
| int ch, i; |
| |
| /* deinterleave and remap input samples */ |
| for (ch = 0; ch < s->channels; ch++) { |
| const SampleType *sptr; |
| int sinc; |
| |
| /* copy last 256 samples of previous frame to the start of the current frame */ |
| memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE], |
| AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); |
| |
| /* deinterleave */ |
| sinc = s->channels; |
| sptr = samples + s->channel_map[ch]; |
| for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) { |
| s->planar_samples[ch][i] = *sptr; |
| sptr += sinc; |
| } |
| } |
| } |
| |
| |
| /** |
| * Apply the MDCT to input samples to generate frequency coefficients. |
| * This applies the KBD window and normalizes the input to reduce precision |
| * loss due to fixed-point calculations. |
| */ |
| void AC3_NAME(apply_mdct)(AC3EncodeContext *s) |
| { |
| int blk, ch; |
| |
| for (ch = 0; ch < s->channels; ch++) { |
| for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { |
| AC3Block *block = &s->blocks[blk]; |
| const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE]; |
| |
| s->apply_window(&s->dsp, s->windowed_samples, input_samples, |
| s->mdct->window, AC3_WINDOW_SIZE); |
| |
| if (s->fixed_point) |
| block->coeff_shift[ch+1] = s->normalize_samples(s); |
| |
| s->mdct->fft.mdct_calcw(&s->mdct->fft, block->mdct_coef[ch+1], |
| s->windowed_samples); |
| } |
| } |
| } |
| |
| |
| /** |
| * Calculate a single coupling coordinate. |
| */ |
| static inline float calc_cpl_coord(float energy_ch, float energy_cpl) |
| { |
| float coord = 0.125; |
| if (energy_cpl > 0) |
| coord *= sqrtf(energy_ch / energy_cpl); |
| return coord; |
| } |
| |
| |
| /** |
| * Calculate coupling channel and coupling coordinates. |
| * TODO: Currently this is only used for the floating-point encoder. I was |
| * able to make it work for the fixed-point encoder, but quality was |
| * generally lower in most cases than not using coupling. If a more |
| * adaptive coupling strategy were to be implemented it might be useful |
| * at that time to use coupling for the fixed-point encoder as well. |
| */ |
| void AC3_NAME(apply_channel_coupling)(AC3EncodeContext *s) |
| { |
| #if CONFIG_AC3ENC_FLOAT |
| LOCAL_ALIGNED_16(float, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); |
| LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); |
| 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)); |
| memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*fixed_cpl_coords)); |
| |
| /* 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 < AC3_MAX_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 to +/- 1.0 in order to be encoded */ |
| s->dsp.vector_clipf(cpl_coef, cpl_coef, -1.0f, 1.0f, num_cpl_coefs); |
| |
| /* scale coupling coefficients from float to 24-bit fixed-point */ |
| s->ac3dsp.float_to_fixed24(&block->fixed_coef[CPL_CH][cpl_start], |
| 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 < AC3_MAX_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++; |
| } |
| |
| /* determine which blocks to send new coupling coordinates for */ |
| for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { |
| AC3Block *block = &s->blocks[blk]; |
| AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL; |
| int new_coords = 0; |
| CoefSumType coord_diff[AC3_MAX_CHANNELS] = {0,}; |
| |
| if (block->cpl_in_use) { |
| /* calculate coupling coordinates for all blocks and calculate the |
| average difference between coordinates in successive blocks */ |
| 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]); |
| if (blk > 0 && block0->cpl_in_use && |
| block0->channel_in_cpl[ch]) { |
| coord_diff[ch] += fabs(cpl_coords[blk-1][ch][bnd] - |
| cpl_coords[blk ][ch][bnd]); |
| } |
| } |
| coord_diff[ch] /= s->num_cpl_bands; |
| } |
| |
| /* 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) { |
| new_coords = 1; |
| } else if (!block0->cpl_in_use) { |
| new_coords = 1; |
| } else { |
| for (ch = 1; ch <= s->fbw_channels; ch++) { |
| if (block->channel_in_cpl[ch] && !block0->channel_in_cpl[ch]) { |
| new_coords = 1; |
| break; |
| } |
| } |
| if (!new_coords) { |
| for (ch = 1; ch <= s->fbw_channels; ch++) { |
| if (block->channel_in_cpl[ch] && coord_diff[ch] > 0.04) { |
| new_coords = 1; |
| break; |
| } |
| } |
| } |
| } |
| } |
| block->new_cpl_coords = new_coords; |
| } |
| |
| /* 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 < AC3_MAX_BLOCKS) { |
| int blk1; |
| CoefSumType energy_cpl; |
| AC3Block *block = &s->blocks[blk]; |
| |
| if (!block->cpl_in_use) { |
| blk++; |
| continue; |
| } |
| |
| energy_cpl = energy[blk][CPL_CH][bnd]; |
| blk1 = blk+1; |
| while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) { |
| if (s->blocks[blk1].cpl_in_use) |
| energy_cpl += energy[blk1][CPL_CH][bnd]; |
| blk1++; |
| } |
| |
| for (ch = 1; ch <= s->fbw_channels; ch++) { |
| CoefType energy_ch; |
| if (!block->channel_in_cpl[ch]) |
| continue; |
| energy_ch = energy[blk][ch][bnd]; |
| blk1 = blk+1; |
| while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) { |
| if (s->blocks[blk1].cpl_in_use) |
| 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 < AC3_MAX_BLOCKS; blk++) { |
| AC3Block *block = &s->blocks[blk]; |
| if (!block->cpl_in_use || !block->new_cpl_coords) |
| continue; |
| |
| s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1], |
| cpl_coords[blk][1], |
| s->fbw_channels * 16); |
| 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; |
| |
| /* 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); |
| #endif /* CONFIG_AC3ENC_FLOAT */ |
| } |
| |
| |
| /** |
| * Determine rematrixing flags for each block and band. |
| */ |
| void AC3_NAME(compute_rematrixing_strategy)(AC3EncodeContext *s) |
| { |
| int nb_coefs; |
| int blk, bnd, i; |
| AC3Block *block, *av_uninit(block0); |
| |
| if (s->channel_mode != AC3_CHMODE_STEREO) |
| return; |
| |
| for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { |
| block = &s->blocks[blk]; |
| block->new_rematrixing_strategy = !blk; |
| |
| if (!s->rematrixing_enabled) { |
| block0 = block; |
| continue; |
| } |
| |
| block->num_rematrixing_bands = 4; |
| if (block->cpl_in_use) { |
| block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61); |
| block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37); |
| if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands) |
| block->new_rematrixing_strategy = 1; |
| } |
| nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]); |
| |
| for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { |
| /* calculate calculate sum of squared coeffs for one band in one block */ |
| int start = ff_ac3_rematrix_band_tab[bnd]; |
| int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]); |
| CoefSumType sum[4] = {0,}; |
| for (i = start; i < end; i++) { |
| CoefType lt = block->mdct_coef[1][i]; |
| CoefType rt = block->mdct_coef[2][i]; |
| CoefType md = lt + rt; |
| CoefType sd = lt - rt; |
| MAC_COEF(sum[0], lt, lt); |
| MAC_COEF(sum[1], rt, rt); |
| MAC_COEF(sum[2], md, md); |
| MAC_COEF(sum[3], sd, sd); |
| } |
| |
| /* compare sums to determine if rematrixing will be used for this band */ |
| if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1])) |
| block->rematrixing_flags[bnd] = 1; |
| else |
| block->rematrixing_flags[bnd] = 0; |
| |
| /* determine if new rematrixing flags will be sent */ |
| if (blk && |
| block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) { |
| block->new_rematrixing_strategy = 1; |
| } |
| } |
| block0 = block; |
| } |
| } |
