mirror of https://github.com/FFmpeg/FFmpeg.git
Function pointers are used for templated functions instead of needlessly duplicating many functions.pull/2/head
Justin Ruggles
14 years ago
parent
e754dfc0bb
commit
e0cc66df61
8 changed files with 577 additions and 445 deletions
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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 Libav. |
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* |
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* Libav 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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* Libav 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 Libav; 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 "ac3enc.h" |
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/**
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* Deinterleave input samples. |
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* Channels are reordered from Libav's default order to AC-3 order. |
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*/ |
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void AC3_NAME(deinterleave_input_samples)(AC3EncodeContext *s, |
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const SampleType *samples) |
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{ |
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int ch, i; |
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/* deinterleave and remap input samples */ |
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for (ch = 0; ch < s->channels; ch++) { |
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const SampleType *sptr; |
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int sinc; |
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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_FRAME_SIZE], |
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AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); |
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/* deinterleave */ |
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sinc = s->channels; |
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sptr = samples + s->channel_map[ch]; |
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for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) { |
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s->planar_samples[ch][i] = *sptr; |
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sptr += sinc; |
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} |
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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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void AC3_NAME(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 < AC3_MAX_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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s->apply_window(&s->dsp, 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] = s->normalize_samples(s); |
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s->mdct->fft.mdct_calcw(&s->mdct->fft, 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 a single coupling coordinate. |
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*/ |
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static inline float calc_cpl_coord(float energy_ch, float energy_cpl) |
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{ |
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float coord = 0.125; |
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if (energy_cpl > 0) |
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coord *= sqrtf(energy_ch / energy_cpl); |
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return coord; |
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} |
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/**
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* Calculate coupling channel and coupling coordinates. |
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* TODO: Currently this is only used for the floating-point encoder. I was |
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* able to make it work for the fixed-point encoder, but quality was |
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* generally lower in most cases than not using coupling. If a more |
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* adaptive coupling strategy were to be implemented it might be useful |
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* at that time to use coupling for the fixed-point encoder as well. |
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*/ |
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void AC3_NAME(apply_channel_coupling)(AC3EncodeContext *s) |
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{ |
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#if CONFIG_AC3ENC_FLOAT |
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LOCAL_ALIGNED_16(float, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); |
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LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); |
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int blk, ch, bnd, i, j; |
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CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}}; |
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int num_cpl_coefs = s->num_cpl_subbands * 12; |
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memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); |
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memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*fixed_cpl_coords)); |
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/* calculate coupling channel from fbw channels */ |
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for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { |
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AC3Block *block = &s->blocks[blk]; |
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CoefType *cpl_coef = &block->mdct_coef[CPL_CH][s->start_freq[CPL_CH]]; |
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if (!block->cpl_in_use) |
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continue; |
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memset(cpl_coef-1, 0, (num_cpl_coefs+4) * 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][s->start_freq[CPL_CH]]; |
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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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/* note: coupling start bin % 4 will always be 1 and num_cpl_coefs
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will always be a multiple of 12, so we need to subtract 1 from |
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the start and add 4 to the length when using optimized |
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functions which require 16-byte alignment. */ |
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/* coefficients must be clipped to +/- 1.0 in order to be encoded */ |
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s->dsp.vector_clipf(cpl_coef-1, cpl_coef-1, -1.0f, 1.0f, num_cpl_coefs+4); |
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/* scale coupling coefficients from float to 24-bit fixed-point */ |
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s->ac3dsp.float_to_fixed24(&block->fixed_coef[CPL_CH][s->start_freq[CPL_CH]-1], |
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cpl_coef-1, num_cpl_coefs+4); |
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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 < AC3_MAX_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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/* determine which blocks to send new coupling coordinates for */ |
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for (blk = 0; blk < AC3_MAX_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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int new_coords = 0; |
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CoefSumType coord_diff[AC3_MAX_CHANNELS] = {0,}; |
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if (block->cpl_in_use) { |
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/* calculate coupling coordinates for all blocks and calculate the
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average difference between coordinates in successive blocks */ |
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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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if (blk > 0 && block0->cpl_in_use && |
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block0->channel_in_cpl[ch]) { |
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coord_diff[ch] += fabs(cpl_coords[blk-1][ch][bnd] - |
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cpl_coords[blk ][ch][bnd]); |
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} |
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} |
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coord_diff[ch] /= s->num_cpl_bands; |
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} |
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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) { |
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new_coords = 1; |
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} else if (!block0->cpl_in_use) { |
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new_coords = 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] && !block0->channel_in_cpl[ch]) { |
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new_coords = 1; |
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break; |
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} |
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} |
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if (!new_coords) { |
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for (ch = 1; ch <= s->fbw_channels; ch++) { |
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if (block->channel_in_cpl[ch] && coord_diff[ch] > 0.04) { |
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new_coords = 1; |
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break; |
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} |
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} |
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} |
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} |
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} |
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block->new_cpl_coords = new_coords; |
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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 < AC3_MAX_BLOCKS) { |
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int blk1; |
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CoefSumType energy_cpl; |
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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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energy_cpl = energy[blk][CPL_CH][bnd]; |
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blk1 = blk+1; |
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while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) { |
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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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blk1++; |
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} |
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for (ch = 1; ch <= s->fbw_channels; ch++) { |
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CoefType energy_ch; |
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if (!block->channel_in_cpl[ch]) |
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continue; |
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energy_ch = energy[blk][ch][bnd]; |
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blk1 = blk+1; |
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while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) { |
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if (s->blocks[blk1].cpl_in_use) |
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energy_ch += energy[blk1][ch][bnd]; |
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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 < AC3_MAX_BLOCKS; blk++) { |
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AC3Block *block = &s->blocks[blk]; |
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if (!block->cpl_in_use || !block->new_cpl_coords) |
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continue; |
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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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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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/* 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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#endif /* CONFIG_AC3ENC_FLOAT */ |
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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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void AC3_NAME(compute_rematrixing_strategy)(AC3EncodeContext *s) |
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{ |
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int nb_coefs; |
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int blk, bnd, i; |
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AC3Block *block, *av_uninit(block0); |
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if (s->channel_mode != AC3_CHMODE_STEREO) |
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return; |
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for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { |
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block = &s->blocks[blk]; |
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block->new_rematrixing_strategy = !blk; |
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if (!s->rematrixing_enabled) { |
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block0 = block; |
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continue; |
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} |
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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); |
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if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands) |
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block->new_rematrixing_strategy = 1; |
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} |
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nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]); |
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for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { |
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/* calculate calculate sum of squared coeffs for one band in one block */ |
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int start = ff_ac3_rematrix_band_tab[bnd]; |
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int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]); |
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CoefSumType sum[4] = {0,}; |
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for (i = start; i < end; i++) { |
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CoefType lt = block->mdct_coef[1][i]; |
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CoefType rt = block->mdct_coef[2][i]; |
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CoefType md = lt + rt; |
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CoefType sd = lt - rt; |
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MAC_COEF(sum[0], lt, lt); |
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MAC_COEF(sum[1], rt, rt); |
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MAC_COEF(sum[2], md, md); |
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MAC_COEF(sum[3], sd, sd); |
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} |
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/* compare sums to determine if rematrixing will be used for this band */ |
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if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1])) |
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block->rematrixing_flags[bnd] = 1; |
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else |
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block->rematrixing_flags[bnd] = 0; |
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/* determine if new rematrixing flags will be sent */ |
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if (blk && |
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block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) { |
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block->new_rematrixing_strategy = 1; |
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} |
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} |
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block0 = block; |
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} |
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} |
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