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-rw-r--r--libswresample/dither.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/libswresample/dither.c b/libswresample/dither.c
new file mode 100644
index 0000000000..d0193dda46
--- /dev/null
+++ b/libswresample/dither.c
@@ -0,0 +1,147 @@
+/*
+ * 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"
+
+void 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((len + TMP_EXTRA) * sizeof(double));
+ int i;
+
+ 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);
+}
+
+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/(1L<<31);
+ if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15);
+ if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7);
+ }
+ if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16;
+ if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
+ if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<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);
+
+ 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 (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && 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;
+ }
+
+ av_assert0(!s->preout.count);
+ s->dither.noise = s->preout;
+ s->dither.temp = s->preout;
+ if (s->dither.method > SWR_DITHER_NS) {
+ s->dither.noise.bps = 4;
+ s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;
+ s->dither.noise_scale = 1;
+ }
+
+ 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