1 files changed, 67 insertions, 0 deletions
diff --git a/libswresample/dither_template.c b/libswresample/dither_template.c
new file mode 100644
index 0000000000..4af7312779
--- /dev/null
+++ b/libswresample/dither_template.c
@@ -0,0 +1,67 @@
+
+#if defined(TEMPLATE_DITHER_DBL)
+#    define RENAME(N) N ## _double
+#    define DELEM  double
+#    define CLIP(v)
+
+#elif defined(TEMPLATE_DITHER_FLT)
+#    define RENAME(N) N ## _float
+#    define DELEM  float
+#    define CLIP(v)
+
+#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