mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2026-11-06 05:17:42 +00:00
Nathan Moinvaziri
93a0f9df9d
Each step tested the scalefactor difference of every previous candidate inside the loop. Computing the range of predecessors within the allowed difference first keeps the output identical and makes AAC encoding about 3.5% faster.
92 lines
3.0 KiB
C
92 lines
3.0 KiB
C
/*
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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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#include <float.h>
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#include <math.h>
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#include "config.h"
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#include "libavutil/common.h"
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#include "libavutil/macros.h"
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#include "aacencdsp.h"
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static void abs_pow34_v(float *out, const float *in, const int size)
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{
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for (int i = 0; i < size; i++) {
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float a = fabsf(in[i]);
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out[i] = sqrtf(a * sqrtf(a));
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}
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}
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static void quantize_bands(int *out, const float *in, const float *scaled,
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int size, int is_signed, int maxval, const float Q34,
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const float rounding)
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{
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for (int i = 0; i < size; i++) {
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float qc = scaled[i] * Q34;
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int tmp = (int)FFMIN((float)(qc + rounding), (float)maxval);
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if (is_signed && in[i] < 0.0f) {
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tmp = -tmp;
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}
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out[i] = tmp;
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}
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}
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/* One NMR scalefactor-trellis Viterbi step, for each current-band candidate, find the
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* previous-band candidate minimising dpp[op] + lamsf[d] then set
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* dp[o] = node[o] + that cost and record the back-pointer bp[o] */
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static void nmr_trellis_step_c(float *dp, uint8_t *bp, const float *dpp,
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const float *node, const float *lamsf,
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int n_cur, int n_prev, int base, int step, int mdiff)
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{
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/* d = base + (o - op) * step lies in [-mdiff, mdiff] for op in [o - dlo, o + dhi] */
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const int dlo = FFUDIV(mdiff - base, step);
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const int dhi = FFUDIV(mdiff + base, step);
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for (int o = 0; o < n_cur; o++) {
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const int op_end = FFMIN(n_prev, o + dhi + 1);
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const int edge = base + o * step + mdiff;
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int best = -1;
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float bestc = FLT_MAX;
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for (int op = FFMAX(0, o - dlo); op < op_end; op++) {
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float c = dpp[op] + lamsf[edge - op * step];
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if (c < bestc) {
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bestc = c;
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best = op;
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}
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}
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bp[o] = best < 0 ? 0 : best;
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dp[o] = best < 0 ? FLT_MAX : node[o] + bestc;
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}
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}
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void ff_aacenc_dsp_init(AACEncDSPContext *s)
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{
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s->abs_pow34 = abs_pow34_v;
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s->quant_bands = quantize_bands;
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s->nmr_trellis_step = nmr_trellis_step_c;
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#if ARCH_RISCV
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ff_aacenc_dsp_init_riscv(s);
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#elif ARCH_X86 && HAVE_X86ASM
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ff_aacenc_dsp_init_x86(s);
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#elif ARCH_AARCH64
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ff_aacenc_dsp_init_aarch64(s);
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#endif
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}
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