move to new cspot

components/spotify/cspot/bell/main/audio-dsp/AudioMixer.cpp

@@ -0,0 +1,39 @@
+#include "AudioMixer.h"
+
+using namespace bell;
+
+AudioMixer::AudioMixer() {
+}
+
+std::unique_ptr<StreamInfo> AudioMixer::process(std::unique_ptr<StreamInfo> info) {
+    std::scoped_lock lock(this->accessMutex);
+    if (info->numChannels != from) {
+        throw std::runtime_error("AudioMixer: Input channel count does not match configuration");
+    }
+    info->numChannels = to;
+
+    for (auto &singleConf : mixerConfig) {
+        if (singleConf.source.size() == 1) {
+            if (singleConf.source[0] == singleConf.destination) {
+                continue;
+            }
+            // Copy channel
+            for (int i = 0; i < info->numSamples; i++) {
+                info->data[singleConf.destination][i] = info->data[singleConf.source[0]][i];
+            }
+        } else {
+            // Mix channels
+            float sample = 0.0f;
+            for (int i = 0; i < info->numSamples; i++) {
+                sample = 0.0;
+                for (auto &source : singleConf.source) {
+                    sample += info->data[source][i];
+                }
+                
+                info->data[singleConf.destination][i] = sample / (float) singleConf.source.size();
+            }
+        }
+    }
+
+    return info;
+}