134dba9544
xHE-AAC relies on the same postfilter mechanism that Opus uses to improve clarity (albeit with a steeper deemphasis filter). The code to apply it is identical, it's still just a simple IIR low-pass filter. This commit makes it possible to use alternative constants.
69 lines
1.9 KiB
C
69 lines
1.9 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 "config.h"
|
|
#include "libavutil/attributes.h"
|
|
#include "libavutil/mem_internal.h"
|
|
#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, const float *weights, int len)
|
|
{
|
|
const float c = weights[0];
|
|
for (int i = 0; i < len; i++)
|
|
coeff = y[i] = x[i] + coeff*c;
|
|
|
|
return coeff;
|
|
}
|
|
|
|
av_cold void ff_opus_dsp_init(OpusDSP *ctx)
|
|
{
|
|
ctx->postfilter = postfilter_c;
|
|
ctx->deemphasis = deemphasis_c;
|
|
|
|
#if ARCH_AARCH64
|
|
ff_opus_dsp_init_aarch64(ctx);
|
|
#elif ARCH_RISCV
|
|
ff_opus_dsp_init_riscv(ctx);
|
|
#elif ARCH_X86
|
|
ff_opus_dsp_init_x86(ctx);
|
|
#endif
|
|
}
|