mirror of
https://github.com/ossrs/srs.git
synced 2025-03-09 15:49:59 +00:00
84 lines
2.8 KiB
C
84 lines
2.8 KiB
C
/*
|
|
* This file is part of libswresample
|
|
*
|
|
* libswresample 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.
|
|
*
|
|
* libswresample 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 libswresample; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#if defined(TEMPLATE_DITHER_DBL)
|
|
# define RENAME(N) N ## _double
|
|
# define DELEM double
|
|
# define CLIP(v) while(0)
|
|
|
|
#elif defined(TEMPLATE_DITHER_FLT)
|
|
# define RENAME(N) N ## _float
|
|
# define DELEM float
|
|
# define CLIP(v) while(0)
|
|
|
|
#elif defined(TEMPLATE_DITHER_S32)
|
|
# define RENAME(N) N ## _int32
|
|
# define DELEM int32_t
|
|
# define CLIP(v) v = FFMAX(FFMIN(v, INT32_MAX), INT32_MIN)
|
|
|
|
#elif defined(TEMPLATE_DITHER_S16)
|
|
# define RENAME(N) N ## _int16
|
|
# define DELEM int16_t
|
|
# define CLIP(v) v = FFMAX(FFMIN(v, INT16_MAX), INT16_MIN)
|
|
|
|
#else
|
|
ERROR
|
|
#endif
|
|
|
|
void RENAME(swri_noise_shaping)(SwrContext *s, AudioData *dsts, const AudioData *srcs, const AudioData *noises, int count){
|
|
int pos = s->dither.ns_pos;
|
|
int i, j, ch;
|
|
int taps = s->dither.ns_taps;
|
|
float S = s->dither.ns_scale;
|
|
float S_1 = s->dither.ns_scale_1;
|
|
|
|
av_assert2((taps&3) != 2);
|
|
av_assert2((taps&3) != 3 || s->dither.ns_coeffs[taps] == 0);
|
|
|
|
for (ch=0; ch<srcs->ch_count; ch++) {
|
|
const float *noise = ((const float *)noises->ch[ch]) + s->dither.noise_pos;
|
|
const DELEM *src = (const DELEM*)srcs->ch[ch];
|
|
DELEM *dst = (DELEM*)dsts->ch[ch];
|
|
float *ns_errors = s->dither.ns_errors[ch];
|
|
const float *ns_coeffs = s->dither.ns_coeffs;
|
|
pos = s->dither.ns_pos;
|
|
for (i=0; i<count; i++) {
|
|
double d1, d = src[i]*S_1;
|
|
for(j=0; j<taps-2; j+=4) {
|
|
d -= ns_coeffs[j ] * ns_errors[pos + j ]
|
|
+ns_coeffs[j + 1] * ns_errors[pos + j + 1]
|
|
+ns_coeffs[j + 2] * ns_errors[pos + j + 2]
|
|
+ns_coeffs[j + 3] * ns_errors[pos + j + 3];
|
|
}
|
|
if(j < taps)
|
|
d -= ns_coeffs[j] * ns_errors[pos + j];
|
|
pos = pos ? pos - 1 : taps - 1;
|
|
d1 = rint(d + noise[i]);
|
|
ns_errors[pos + taps] = ns_errors[pos] = d1 - d;
|
|
d1 *= S;
|
|
CLIP(d1);
|
|
dst[i] = d1;
|
|
}
|
|
}
|
|
|
|
s->dither.ns_pos = pos;
|
|
}
|
|
|
|
#undef RENAME
|
|
#undef DELEM
|
|
#undef CLIP
|