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- /*
- * Copyright (C) 2012-2013 Michael Niedermayer (michaelni@gmx.at)
- *
- * 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
- */
-
- #include "libavutil/avassert.h"
- #include "swresample_internal.h"
-
- #include "noise_shaping_data.c"
-
- int swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat noise_fmt) {
- double scale = s->dither.noise_scale;
- #define TMP_EXTRA 2
- double *tmp = av_malloc_array(len + TMP_EXTRA, sizeof(double));
- int i;
-
- if (!tmp)
- return AVERROR(ENOMEM);
-
- for(i=0; i<len + TMP_EXTRA; i++){
- double v;
- seed = seed* 1664525 + 1013904223;
-
- switch(s->dither.method){
- case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
- default:
- av_assert0(s->dither.method < SWR_DITHER_NB);
- v = ((double)seed) / UINT_MAX;
- seed = seed*1664525 + 1013904223;
- v-= ((double)seed) / UINT_MAX;
- break;
- }
- tmp[i] = v;
- }
-
- for(i=0; i<len; i++){
- double v;
-
- switch(s->dither.method){
- default:
- av_assert0(s->dither.method < SWR_DITHER_NB);
- v = tmp[i];
- break;
- case SWR_DITHER_TRIANGULAR_HIGHPASS :
- v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
- break;
- }
-
- v*= scale;
-
- switch(noise_fmt){
- case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;
- case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;
- case AV_SAMPLE_FMT_FLTP: ((float *)dst)[i] = v; break;
- case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;
- default: av_assert0(0);
- }
- }
-
- av_free(tmp);
- return 0;
- }
-
- av_cold int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)
- {
- int i;
- double scale = 0;
-
- if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)
- return AVERROR(EINVAL);
-
- out_fmt = av_get_packed_sample_fmt(out_fmt);
- in_fmt = av_get_packed_sample_fmt( in_fmt);
-
- if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
- if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1LL<<31);
- if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1LL<<15);
- if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1LL<< 7);
- }
- if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;
- if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1<<16;
- if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<24;
- if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<8;
-
- scale *= s->dither.scale;
-
- if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)
- scale *= 1<<(32-s->dither.output_sample_bits);
-
- if (scale == 0) {
- s->dither.method = 0;
- return 0;
- }
-
- s->dither.ns_pos = 0;
- s->dither.noise_scale= scale;
- s->dither.ns_scale = scale;
- s->dither.ns_scale_1 = scale ? 1/scale : 0;
- memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));
- for (i=0; filters[i].coefs; i++) {
- const filter_t *f = &filters[i];
- if (llabs(s->out_sample_rate - f->rate)*20 <= f->rate && f->name == s->dither.method) {
- int j;
- s->dither.ns_taps = f->len;
- for (j=0; j<f->len; j++)
- s->dither.ns_coeffs[j] = f->coefs[j];
- s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));
- break;
- }
- }
- if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {
- av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
- s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;
- }
-
- return 0;
- }
-
- #define TEMPLATE_DITHER_S16
- #include "dither_template.c"
- #undef TEMPLATE_DITHER_S16
-
- #define TEMPLATE_DITHER_S32
- #include "dither_template.c"
- #undef TEMPLATE_DITHER_S32
-
- #define TEMPLATE_DITHER_FLT
- #include "dither_template.c"
- #undef TEMPLATE_DITHER_FLT
-
- #define TEMPLATE_DITHER_DBL
- #include "dither_template.c"
- #undef TEMPLATE_DITHER_DBL
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