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FFmpeg/libavcodec/opusdsp.c
Rémi Denis-Courmont 8009581912 lavc/opusdsp: RISC-V V (128-bit) postfilter
This is implemented for a vector size of 128-bit. Since the scalar
product in the inner loop covers 5 samples or 160 bits, we need a group
multipler of 2.

To avoid reconfiguring the vector type, the outer loop, which loads
multiple input samples sticks to the same multipler. Consequently, the
outer loop loads 8 samples per iteration. This is safe since the minimum
period of the CELT codec is 15 samples.

The same code would also work, albeit needlessly inefficiently with a
vector length of 256 bits. A proper implementation will follow instead.
2022-10-10 02:22:10 +02:00

67 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 "config.h"
#include "libavutil/attributes.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, int len)
{
for (int i = 0; i < len; i++)
coeff = y[i] = x[i] + coeff*CELT_EMPH_COEFF;
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
}