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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-11-26 19:01:44 +02:00
FFmpeg/libavcodec/opusdsp.c
Lynne 4d2f62150d aarch64/opusdsp: implement NEON accelerated postfilter and deemphasis
153372 UNITS in postfilter_c,   65536 runs,      0 skips
73164 UNITS in postfilter_neon,   65536 runs,      0 skips -> 2.1x speedup

80591 UNITS in deemphasis_c,  131072 runs,      0 skips
43969 UNITS in deemphasis_neon,  131072 runs,      0 skips -> 1.83x speedup

Total decoder speedup: ~15% on a Raspberry Pi 3 (from 28.1x to 33.5x realtime)

Deemphasis SIMD based on the following unrolling:
const float c1 = CELT_EMPH_COEFF, c2 = c1*c1, c3 = c2*c1, c4 = c3*c1;
float state = coeff;

for (int i = 0; i < len; i += 4) {
    y[0] = x[0] + c1*state;
    y[1] = x[1] + c2*state + c1*x[0];
    y[2] = x[2] + c3*state + c1*x[1] + c2*x[0];
    y[3] = x[3] + c4*state + c1*x[2] + c2*x[1] + c3*x[0];

    state = y[3];
    y += 4;
    x += 4;
}

Unlike the x86 version, duplication is used instead of pslldq so
the structure and tables are different.
2019-04-10 01:08:54 +02:00

68 lines
1.8 KiB
C

/*
* 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
*/
#include "opusdsp.h"
static void postfilter_c(float *data, int period, float *gains, int len)
{
const float g0 = gains[0];
const float g1 = gains[1];
const float g2 = gains[2];
float x4 = data[-period - 2];
float x3 = data[-period - 1];
float x2 = data[-period + 0];
float x1 = data[-period + 1];
for (int i = 0; i < len; i++) {
float x0 = data[i - period + 2];
data[i] += g0 * x2 +
g1 * (x1 + x3) +
g2 * (x0 + x4);
x4 = x3;
x3 = x2;
x2 = x1;
x1 = x0;
}
}
static float deemphasis_c(float *y, float *x, float coeff, int len)
{
float state = coeff;
for (int i = 0; i < len; i++) {
const float tmp = x[i] + state;
state = tmp * CELT_EMPH_COEFF;
y[i] = tmp;
}
return state;
}
av_cold void ff_opus_dsp_init(OpusDSP *ctx)
{
ctx->postfilter = postfilter_c;
ctx->deemphasis = deemphasis_c;
if (ARCH_X86)
ff_opus_dsp_init_x86(ctx);
if (ARCH_AARCH64)
ff_opus_dsp_init_aarch64(ctx);
}