Fixed sampling algorithm

alxrm · Nov 5, 2016 · ab5bdc3 · ab5bdc3
1 parent 8f8f6df
commit ab5bdc3
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Showing 2 changed files with 14 additions and 12 deletions.
diff --git a/app/build.gradle b/app/build.gradle
@@ -27,7 +27,9 @@ dependencies {
 	compile fileTree(dir: 'libs', include: ['*.jar'])
 	compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 	compile 'com.android.support:appcompat-v7:24.2.1'
-	compile 'com.github.alxrm:Audiogram:0.4'
+//	compile 'com.github.alxrm:Audiogram:0.5'
+
+	compile project(':audiowave')
 }
 repositories {
 	mavenCentral()

diff --git a/...main/kotlin/rm/com/audiowave/Samplings.kt → ...c/main/kotlin/rm/com/audiowave/Sampler.kt b/...main/kotlin/rm/com/audiowave/Samplings.kt → ...c/main/kotlin/rm/com/audiowave/Sampler.kt
@@ -25,29 +25,29 @@ object Sampler {
 
   fun downSample(data: ByteArray, targetSize: Int): ByteArray {
     val targetSized = ByteArray(targetSize, { 0 })
-    val reducedSample = mutableListOf<Byte>()
-
     var prevDataIndex = 0
+    var sampledPerChunk = 0F
+    var sumPerChunk = 0F
 
     if (targetSize >= data.size) {
       return targetSized.paste(data)
     }
 
-    data.forEachIndexed { i, byte ->
-      val currentDataIndex = targetSize * i / data.size
+    for (index in 0..data.size) {
+      val currentDataIndex = targetSize * index / data.size
 
       if (prevDataIndex == currentDataIndex) {
-        reducedSample += byte.abs
+        sampledPerChunk += 1
+        sumPerChunk += data[index].abs
       } else {
-        targetSized[currentDataIndex - 1] = reducedSample.average().toByte()
-        reducedSample.clear()
-      }
+        targetSized[prevDataIndex] = (sumPerChunk / sampledPerChunk).toByte()
 
-      prevDataIndex = currentDataIndex
+        sumPerChunk = 0F
+        sampledPerChunk = 0F
+        prevDataIndex = currentDataIndex
+      }
     }
 
-    targetSized[prevDataIndex] = reducedSample.average().toByte()
-
     return targetSized
   }
 }