use rs support library and minSdkVersion 15

app/app.iml

@@ -81,6 +81,7 @@
     </content>
     <orderEntry type="jdk" jdkName="Android API 21 Platform" jdkType="Android SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" exported="" name="renderscript-v8" level="project" />
   </component>
 </module>
 

app/build.gradle

@@ -6,12 +6,12 @@ android {
 
     defaultConfig {
         applicationId "xdsopl.robot36"
-        minSdkVersion 18
+        minSdkVersion 15
         targetSdkVersion 21
         versionCode 1
         versionName "1.0"
         renderscriptTargetApi 19
-        renderscriptSupportMode false
+        renderscriptSupportMode true
     }
     buildTypes {
         release {

app/src/main/java/xdsopl/robot36/DecoderThread.java

@@ -25,9 +25,9 @@ import android.graphics.Paint;
 import android.media.AudioFormat;
 import android.media.AudioRecord;
 import android.media.MediaRecorder;
-import android.renderscript.Allocation;
-import android.renderscript.Element;
-import android.renderscript.RenderScript;
+import android.support.v8.renderscript.Allocation;
+import android.support.v8.renderscript.Element;
+import android.support.v8.renderscript.RenderScript;
 import android.view.SurfaceHolder;
 
 public class DecoderThread extends Thread {