+
+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;
+
+ s->dither.ns_pos = 0;
+ s->dither.noise_scale= scale;
+ s->dither.ns_scale = scale;
+ s->dither.ns_scale_1 = 1/scale;
+ 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;
+ }
+
+ s->dither.noise = 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