stereo to mono conversion

djshaji · Feb 26, 2024 · 51cbffb · 51cbffb
1 parent 46b7d07
commit 51cbffb
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/.idea/misc.xml b/.idea/misc.xml
diff --git a/app/src/main/java/com/shajikhan/ladspa/amprack/AudioDecoder.java b/app/src/main/java/com/shajikhan/ladspa/amprack/AudioDecoder.java
@@ -90,6 +90,7 @@ float[] decode (FileDescriptor fileDescriptor, String mimeType, int _sampleRate)
         extractor.setDataSource(fileDescriptor);
         float scaleFactor = 48000 / sampleRate ;
         MediaFormat format = extractor.getTrackFormat(0);
+        int channels = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);
         String mime = format.getString(MediaFormat.KEY_MIME);
         Log.d(TAG, String.format ("mimetype: %s", mimeType));
         if (_sampleRate != -1) {
@@ -203,6 +204,16 @@ float[] decode (FileDescriptor fileDescriptor, String mimeType, int _sampleRate)
         Log.i(TAG, "decode: returning " +
                 String.format("%d audio samples", decoded.length));
 
+        if (channels > 1) {
+            Log.d(TAG, String.format ("channels: %d, converting to mono", channels));
+            float[] mono = new float [(decoded.length/channels) + 1];
+            for (int i = 0, k = 0 ; i < decoded.length ; i += channels, k ++) {
+                mono [k] = decoded [i];
+            }
+
+            decoded = mono;
+        }
+
         if (sampleRate == 48000)
             return decoded;