437 lines
15 KiB
C
437 lines
15 KiB
C
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/*
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* AC-3 encoder float/fixed template
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* Copyright (c) 2000 Fabrice Bellard
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* Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com>
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* Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* AC-3 encoder float/fixed template
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*/
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#include <stdint.h>
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#include "libavutil/attributes.h"
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#include "libavutil/internal.h"
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#include "audiodsp.h"
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#include "internal.h"
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#include "ac3enc.h"
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#include "eac3enc.h"
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int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s)
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{
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int ch;
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FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE *
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sizeof(*s->windowed_samples), alloc_fail);
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FF_ALLOC_ARRAY_OR_GOTO(s->avctx, s->planar_samples, s->channels, sizeof(*s->planar_samples),
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alloc_fail);
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for (ch = 0; ch < s->channels; ch++) {
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FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch],
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(AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
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alloc_fail);
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}
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return 0;
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alloc_fail:
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return AVERROR(ENOMEM);
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}
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/*
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* Copy input samples.
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* Channels are reordered from FFmpeg's default order to AC-3 order.
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*/
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static void copy_input_samples(AC3EncodeContext *s, SampleType **samples)
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{
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int ch;
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/* copy and remap input samples */
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for (ch = 0; ch < s->channels; ch++) {
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/* copy last 256 samples of previous frame to the start of the current frame */
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memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_BLOCK_SIZE * s->num_blocks],
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AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
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/* copy new samples for current frame */
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memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE],
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samples[s->channel_map[ch]],
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AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0]));
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}
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}
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/*
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* Apply the MDCT to input samples to generate frequency coefficients.
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* This applies the KBD window and normalizes the input to reduce precision
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* loss due to fixed-point calculations.
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*/
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static void apply_mdct(AC3EncodeContext *s)
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{
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int blk, ch;
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for (ch = 0; ch < s->channels; ch++) {
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
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#if CONFIG_AC3ENC_FLOAT
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s->fdsp->vector_fmul(s->windowed_samples, input_samples,
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s->mdct_window, AC3_WINDOW_SIZE);
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#else
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s->ac3dsp.apply_window_int16(s->windowed_samples, input_samples,
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s->mdct_window, AC3_WINDOW_SIZE);
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if (s->fixed_point)
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block->coeff_shift[ch+1] = normalize_samples(s);
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#endif
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s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1],
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s->windowed_samples);
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}
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}
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}
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/*
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* Calculate coupling channel and coupling coordinates.
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*/
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static void apply_channel_coupling(AC3EncodeContext *s)
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{
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LOCAL_ALIGNED_16(CoefType, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
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#if CONFIG_AC3ENC_FLOAT
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LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
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#else
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int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords;
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#endif
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int av_uninit(blk), ch, bnd, i, j;
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CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}};
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int cpl_start, num_cpl_coefs;
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memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
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#if CONFIG_AC3ENC_FLOAT
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memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
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#endif
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/* align start to 16-byte boundary. align length to multiple of 32.
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note: coupling start bin % 4 will always be 1 */
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cpl_start = s->start_freq[CPL_CH] - 1;
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num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32);
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cpl_start = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs;
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/* calculate coupling channel from fbw channels */
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start];
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if (!block->cpl_in_use)
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continue;
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memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef));
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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CoefType *ch_coef = &block->mdct_coef[ch][cpl_start];
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if (!block->channel_in_cpl[ch])
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continue;
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for (i = 0; i < num_cpl_coefs; i++)
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cpl_coef[i] += ch_coef[i];
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}
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/* coefficients must be clipped in order to be encoded */
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clip_coefficients(&s->adsp, cpl_coef, num_cpl_coefs);
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}
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/* calculate energy in each band in coupling channel and each fbw channel */
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/* TODO: possibly use SIMD to speed up energy calculation */
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bnd = 0;
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i = s->start_freq[CPL_CH];
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while (i < s->cpl_end_freq) {
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int band_size = s->cpl_band_sizes[bnd];
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for (ch = CPL_CH; ch <= s->fbw_channels; ch++) {
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch]))
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continue;
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for (j = 0; j < band_size; j++) {
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CoefType v = block->mdct_coef[ch][i+j];
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MAC_COEF(energy[blk][ch][bnd], v, v);
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}
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}
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}
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i += band_size;
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bnd++;
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}
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/* calculate coupling coordinates for all blocks for all channels */
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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if (!block->cpl_in_use)
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continue;
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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if (!block->channel_in_cpl[ch])
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continue;
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for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
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cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
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energy[blk][CPL_CH][bnd]);
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}
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}
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}
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/* determine which blocks to send new coupling coordinates for */
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
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memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords));
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if (block->cpl_in_use) {
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/* send new coordinates if this is the first block, if previous
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* block did not use coupling but this block does, the channels
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* using coupling has changed from the previous block, or the
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* coordinate difference from the last block for any channel is
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* greater than a threshold value. */
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if (blk == 0 || !block0->cpl_in_use) {
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for (ch = 1; ch <= s->fbw_channels; ch++)
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block->new_cpl_coords[ch] = 1;
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} else {
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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if (!block->channel_in_cpl[ch])
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continue;
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if (!block0->channel_in_cpl[ch]) {
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block->new_cpl_coords[ch] = 1;
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} else {
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CoefSumType coord_diff = 0;
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for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
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coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] -
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cpl_coords[blk ][ch][bnd]);
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}
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coord_diff /= s->num_cpl_bands;
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if (coord_diff > NEW_CPL_COORD_THRESHOLD)
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block->new_cpl_coords[ch] = 1;
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}
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}
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}
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}
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}
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/* calculate final coupling coordinates, taking into account reusing of
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coordinates in successive blocks */
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for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
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blk = 0;
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while (blk < s->num_blocks) {
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int av_uninit(blk1);
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AC3Block *block = &s->blocks[blk];
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if (!block->cpl_in_use) {
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blk++;
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continue;
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}
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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CoefSumType energy_ch, energy_cpl;
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if (!block->channel_in_cpl[ch])
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continue;
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energy_cpl = energy[blk][CPL_CH][bnd];
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energy_ch = energy[blk][ch][bnd];
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blk1 = blk+1;
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while (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) {
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if (s->blocks[blk1].cpl_in_use) {
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energy_cpl += energy[blk1][CPL_CH][bnd];
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energy_ch += energy[blk1][ch][bnd];
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}
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blk1++;
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}
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cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl);
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}
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blk = blk1;
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}
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}
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/* calculate exponents/mantissas for coupling coordinates */
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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if (!block->cpl_in_use)
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continue;
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#if CONFIG_AC3ENC_FLOAT
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s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1],
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cpl_coords[blk][1],
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s->fbw_channels * 16);
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#endif
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s->ac3dsp.extract_exponents(block->cpl_coord_exp[1],
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fixed_cpl_coords[blk][1],
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s->fbw_channels * 16);
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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int bnd, min_exp, max_exp, master_exp;
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if (!block->new_cpl_coords[ch])
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continue;
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/* determine master exponent */
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min_exp = max_exp = block->cpl_coord_exp[ch][0];
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for (bnd = 1; bnd < s->num_cpl_bands; bnd++) {
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int exp = block->cpl_coord_exp[ch][bnd];
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min_exp = FFMIN(exp, min_exp);
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max_exp = FFMAX(exp, max_exp);
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}
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master_exp = ((max_exp - 15) + 2) / 3;
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master_exp = FFMAX(master_exp, 0);
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while (min_exp < master_exp * 3)
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master_exp--;
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for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
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block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] -
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master_exp * 3, 0, 15);
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}
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block->cpl_master_exp[ch] = master_exp;
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/* quantize mantissas */
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for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
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int cpl_exp = block->cpl_coord_exp[ch][bnd];
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int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24;
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if (cpl_exp == 15)
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cpl_mant >>= 1;
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else
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cpl_mant -= 16;
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block->cpl_coord_mant[ch][bnd] = cpl_mant;
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}
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}
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}
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if (CONFIG_EAC3_ENCODER && s->eac3)
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ff_eac3_set_cpl_states(s);
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}
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/*
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* Determine rematrixing flags for each block and band.
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*/
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static void compute_rematrixing_strategy(AC3EncodeContext *s)
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{
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int nb_coefs;
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int blk, bnd;
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AC3Block *block, *block0 = NULL;
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if (s->channel_mode != AC3_CHMODE_STEREO)
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return;
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for (blk = 0; blk < s->num_blocks; blk++) {
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block = &s->blocks[blk];
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block->new_rematrixing_strategy = !blk;
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block->num_rematrixing_bands = 4;
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if (block->cpl_in_use) {
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block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61);
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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;
|
||
|
|
}
|