Changeset 1007 for trunk/src/org/apollo/gui/DualPeakTroughWaveFormRenderer.java

Timestamp:

03/08/16 23:22:09 (8 years ago)

Author:

davidb

Message:

Generalization of audio support to allow playback/mixer to be stereo, plus some edits to comments

File:

• trunk/src/org/apollo/gui/DualPeakTroughWaveFormRenderer.java (modified) (6 diffs)

trunk/src/org/apollo/gui/DualPeakTroughWaveFormRenderer.java

@@ -14 +14 @@
         
         private int sampleSize;
+        private int numChannels;
         private boolean isBigEndian;
         private boolean isSigned;
@@ -36 +37 @@
 
                 sampleSize = audioFormat.getSampleSizeInBits();
+                numChannels = audioFormat.getChannels();
                 isSigned = audioFormat.getEncoding().toString().startsWith("PCM_SIGN");
                 isBigEndian = audioFormat.isBigEndian();
@@ -81 +83 @@
                 if (sampleSize == 16) {
                                          
+                        int shift_multiplier = numChannels; // <<1=16-bit-mono, <<2=16-bit-stereo 
                         for (int i = 0; i < aggregationCount; i++) {
                                 
                                 int max = 0, min = 0, sample; // could use short, but int avoids casting everywhere
                                 
-                                int startFrameIndex = (startFrame + (i * aggregationSize)) << 1;
-                                int endFrameIndex = startFrameIndex + (aggregationSize << 1);
+                                int startFrameIndex = (startFrame + (i * aggregationSize)) << shift_multiplier;
+                                int endFrameIndex = startFrameIndex + (aggregationSize << shift_multiplier);
                                 
                                 for (int k = startFrameIndex; k < endFrameIndex; k+=2) {
                         
+                                        // k+=2 works for both mono and stereo
+                                        // in the case of stereo k+=2 alternates between L and R values.
+                                        // net effect is that it still finds the min and max values across
+                                        // all samples: startFrameIndex .. endFrameIndex
+                                         
                                         int lsb, msb;
                                                                  
@@ -128 +136 @@
                 } else if (sampleSize == 8) {
                         
+                        int shift_multiplier = numChannels-1; // <<0=8-bit-mono, <<1=8-bit-stereo
+                        
+                        // 'i' loop below works for either mono or stereo without any adjustment
+                        // for same reason above given for 'k' loop
+                        
                         if (isSigned) {
                   
+                                
                                 // Find the peak within the block of aggregated frames
                                 for (int i = 0; i < amplitudes.length; i++) {
@@ -135 +149 @@
                                         byte max = 0, absmax = -1, sample, abssample;
 
-                                        int startFrameIndex = startFrame + (i * aggregationSize);
-                                        int endFrameIndex = startFrameIndex + aggregationSize;
+                                        int startFrameIndex = (startFrame + (i * aggregationSize)) << shift_multiplier;
+                                        int endFrameIndex = startFrameIndex + (aggregationSize << shift_multiplier);
                                         
                                         for (int k = startFrameIndex; k < endFrameIndex; k++) {
@@ -160 +174 @@
                                         int max = 0, absmax = -1, sample, abssample; // could use short, but int avoid casting everywhere
 
-                                        int startFrameIndex = startFrame + (i * aggregationSize);
-                                        int endFrameIndex = startFrameIndex + aggregationSize;
+                                        int startFrameIndex = (startFrame + (i * aggregationSize)) << shift_multiplier;
+                                        int endFrameIndex = startFrameIndex + (aggregationSize<<shift_multiplier);
                                         
                                         for (int k = startFrameIndex; k < endFrameIndex; k++) {