| /* |
| * 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 FFmpeg. |
| * |
| * FFmpeg 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. |
| * |
| * FFmpeg 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 FFmpeg; 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 "libavutil/attributes.h" |
| #include "libavutil/internal.h" |
| |
| #include "audiodsp.h" |
| #include "internal.h" |
| #include "ac3enc.h" |
| #include "eac3enc.h" |
| |
| |
| int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s) |
| { |
| int ch; |
| |
| if (!FF_ALLOC_TYPED_ARRAY(s->windowed_samples, AC3_WINDOW_SIZE) || |
| !FF_ALLOCZ_TYPED_ARRAY(s->planar_samples, s->channels)) |
| return AVERROR(ENOMEM); |
| |
| for (ch = 0; ch < s->channels; ch++) { |
| if (!(s->planar_samples[ch] = av_mallocz((AC3_FRAME_SIZE + AC3_BLOCK_SIZE) * |
| sizeof(**s->planar_samples)))) |
| return AVERROR(ENOMEM); |
| } |
| return 0; |
| } |
| |
| |
| /* |
| * Copy input samples. |
| * Channels are reordered from FFmpeg's default order to AC-3 order. |
| */ |
| static void copy_input_samples(AC3EncodeContext *s, SampleType **samples) |
| { |
| int ch; |
| |
| /* copy and remap input samples */ |
| for (ch = 0; ch < s->channels; ch++) { |
| /* 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_BLOCK_SIZE * s->num_blocks], |
| AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); |
| |
| /* copy new samples for current frame */ |
| memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE], |
| samples[s->channel_map[ch]], |
| AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0])); |
| } |
| } |
| |
| |
| /* |
| * 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. |
| */ |
| static void apply_mdct(AC3EncodeContext *s) |
| { |
| int blk, ch; |
| |
| for (ch = 0; ch < s->channels; ch++) { |
| for (blk = 0; blk < s->num_blocks; blk++) { |
| AC3Block *block = &s->blocks[blk]; |
| const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE]; |
| |
| #if CONFIG_AC3ENC_FLOAT |
| s->fdsp->vector_fmul(s->windowed_samples, input_samples, |
| s->mdct_window, AC3_WINDOW_SIZE); |
| #else |
| s->ac3dsp.apply_window_int16(s->windowed_samples, input_samples, |
| s->mdct_window, AC3_WINDOW_SIZE); |
| |
| if (s->fixed_point) |
| block->coeff_shift[ch+1] = normalize_samples(s); |
| #endif |
| |
| s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1], |
| s->windowed_samples); |
| } |
| } |
| } |
| |
| |
| /* |
| * Calculate coupling channel and coupling coordinates. |
| */ |
| 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 av_uninit(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->adsp, 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 (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) { |
| 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); |
| } |
| |
| |
| /* |
| * Determine rematrixing flags for each block and band. |
| */ |
| static void compute_rematrixing_strategy(AC3EncodeContext *s) |
| { |
| int nb_coefs; |
| int blk, bnd; |
| AC3Block *block, *block0 = NULL; |
| |
| if (s->channel_mode != AC3_CHMODE_STEREO) |
| return; |
| |
| for (blk = 0; blk < s->num_blocks; blk++) { |
| block = &s->blocks[blk]; |
| block->new_rematrixing_strategy = !blk; |
| |
| 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]); |
| |
| if (!s->rematrixing_enabled) { |
| block0 = block; |
| continue; |
| } |
| |
| for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { |
| /* 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]; |
| sum_square_butterfly(s, sum, block->mdct_coef[1] + start, |
| block->mdct_coef[2] + start, end - start); |
| |
| /* 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; |
| } |
| } |
| |
| |
| int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt, |
| const AVFrame *frame, int *got_packet_ptr) |
| { |
| AC3EncodeContext *s = avctx->priv_data; |
| int ret; |
| |
| if (s->options.allow_per_frame_metadata) { |
| ret = ff_ac3_validate_metadata(s); |
| if (ret) |
| return ret; |
| } |
| |
| if (s->bit_alloc.sr_code == 1 || s->eac3) |
| ff_ac3_adjust_frame_size(s); |
| |
| copy_input_samples(s, (SampleType **)frame->extended_data); |
| |
| apply_mdct(s); |
| |
| if (s->fixed_point) |
| scale_coefficients(s); |
| |
| clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1], |
| AC3_MAX_COEFS * s->num_blocks * s->channels); |
| |
| s->cpl_on = s->cpl_enabled; |
| ff_ac3_compute_coupling_strategy(s); |
| |
| if (s->cpl_on) |
| apply_channel_coupling(s); |
| |
| compute_rematrixing_strategy(s); |
| |
| if (!s->fixed_point) |
| scale_coefficients(s); |
| |
| ff_ac3_apply_rematrixing(s); |
| |
| ff_ac3_process_exponents(s); |
| |
| ret = ff_ac3_compute_bit_allocation(s); |
| if (ret) { |
| av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n"); |
| return ret; |
| } |
| |
| ff_ac3_group_exponents(s); |
| |
| ff_ac3_quantize_mantissas(s); |
| |
| if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size, 0)) < 0) |
| return ret; |
| ff_ac3_output_frame(s, avpkt->data); |
| |
| if (frame->pts != AV_NOPTS_VALUE) |
| avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding); |
| |
| *got_packet_ptr = 1; |
| return 0; |
| } |
