this feature will not last very long, its too hard to maintain, sometimes segfaults when encoder is finised or stops ?

moved into seperate folder, and cleaned up some components

src/engine/encoder/SampleRateUtils.h

@@ -0,0 +1,35 @@
+#pragma once
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+}
+
+namespace engine {
+
+inline int pickSampleRate(const AVCodec *encoder, int sourceRate)
+{
+    if (!encoder->supported_samplerates)
+        return sourceRate;
+
+    for (const int *r = encoder->supported_samplerates; *r != 0; ++r)
+        if (*r == sourceRate)
+            return sourceRate;
+
+    int best = 0;
+    for (const int *r = encoder->supported_samplerates; *r != 0; ++r) {
+        if (*r >= sourceRate) {
+            if (best == 0 || *r < best)
+                best = *r;
+        }
+    }
+    if (best != 0)
+        return best;
+
+    for (const int *r = encoder->supported_samplerates; *r != 0; ++r)
+        if (*r > best)
+            best = *r;
+
+    return best;
+}
+
+} // namespace engine