diff --git a/variablespeed/jni/jni_entry.cc b/variablespeed/jni/jni_entry.cc
index 368d230..93c12ba 100644
--- a/variablespeed/jni/jni_entry.cc
+++ b/variablespeed/jni/jni_entry.cc
@@ -39,7 +39,7 @@
 };
 
 extern "C" {
-JNI_METHOD(playFileDescriptor, void) (JNIEnv*, jclass, int fd, jlong offset,
+JNI_METHOD(playFileDescriptor, void) (JNIEnv*, jclass, jint fd, jlong offset,
     jlong length) {
   MethodLog _("playFileDescriptor");
   AudioEngine::GetEngine()->PlayFileDescriptor(fd, offset, length);
@@ -52,7 +52,7 @@
   AudioEngine::GetEngine()->PlayUri(utf8);
 }
 
-JNI_METHOD(setVariableSpeed, void) (JNIEnv*, jclass, float speed) {
+JNI_METHOD(setVariableSpeed, void) (JNIEnv*, jclass, jfloat speed) {
   MethodLog _("setVariableSpeed");
   AudioEngine::GetEngine()->SetVariableSpeed(speed);
 }
@@ -67,19 +67,19 @@
   AudioEngine::GetEngine()->RequestStop();
 }
 
-JNI_METHOD(getCurrentPosition, int) (JNIEnv*, jclass) {
+JNI_METHOD(getCurrentPosition, jint) (JNIEnv*, jclass) {
   return AudioEngine::GetEngine()->GetCurrentPosition();
 }
 
-JNI_METHOD(getTotalDuration, int) (JNIEnv*, jclass) {
+JNI_METHOD(getTotalDuration, jint) (JNIEnv*, jclass) {
   return AudioEngine::GetEngine()->GetTotalDuration();
 }
 
 JNI_METHOD(initializeEngine, void) (JNIEnv*, jclass,
-    int targetFrames, float windowDuration,
-    float windowOverlapDuration, size_t maxPlayBufferCount,
-    float initialRate, size_t decodeInitialSize, size_t decodeMaxSize,
-    size_t startPositionMillis, int audioStreamType) {
+    jint targetFrames, jfloat windowDuration,
+    jfloat windowOverlapDuration, jint maxPlayBufferCount,
+    jfloat initialRate, jint decodeInitialSize, jint decodeMaxSize,
+    jint startPositionMillis, jint audioStreamType) {
   MethodLog _("initializeEngine");
   AudioEngine::SetEngine(new AudioEngine(targetFrames,
       windowDuration, windowOverlapDuration, maxPlayBufferCount, initialRate,
diff --git a/variablespeed/jni/variablespeed.cc b/variablespeed/jni/variablespeed.cc
index 73ac609..b5d9067 100644
--- a/variablespeed/jni/variablespeed.cc
+++ b/variablespeed/jni/variablespeed.cc
@@ -564,7 +564,7 @@
 }
 
 static void CreateAndRealizeAudioPlayer(SLuint32 slSampleRate,
-    size_t channelCount, SLuint32 slChannels, SLint32 audioStreamType, SLObjectItf &outputMix,
+    SLuint32 channelCount, SLuint32 slChannels, SLint32 audioStreamType, SLObjectItf &outputMix,
     SLObjectItf &audioPlayer, SLEngineItf &engineInterface) {
   // Define the source and sink for the audio player: comes from a buffer queue
   // and goes to the output mix.
diff --git a/variablespeed/jni/variablespeed.h b/variablespeed/jni/variablespeed.h
index 07cba0f..cf856da 100644
--- a/variablespeed/jni/variablespeed.h
+++ b/variablespeed/jni/variablespeed.h
@@ -86,7 +86,7 @@
   bool HasSampleRateAndChannels();
   SLuint32 GetSLSampleRate();
   SLuint32 GetSLChannels();
-  size_t GetChannelCount();
+  SLuint32 GetChannelCount();
 
   // The single global audio engine instance.
   static AudioEngine* audioEngine_;