diff --git a/app/src/main/java/com/frank/ffmpeg/VideoPlayer.java b/app/src/main/java/com/frank/ffmpeg/VideoPlayer.java
index 20fc676..5a76cce 100644
--- a/app/src/main/java/com/frank/ffmpeg/VideoPlayer.java
+++ b/app/src/main/java/com/frank/ffmpeg/VideoPlayer.java
@@ -5,7 +5,7 @@ import android.media.AudioManager;
 import android.media.AudioTrack;
 
 /**
- * 视频播放器
+ * VideoPlayer: using FFmpeg filter
  * Created by frank on 2018/2/1
  */
 public class VideoPlayer {
@@ -15,27 +15,32 @@ public class VideoPlayer {
     }
 
     public native int play(String filePath, Object surface);
+
     public native void setPlayRate(float playRate);
 
     public native int filter(String filePath, Object surface, String filterType);
+
     public native void again();
+
     public native void release();
+
     public native void playAudio(boolean play);
 
     /**
-     * 创建AudioTrack对象，供JNI调用
+     * Create an AudioTrack instance for JNI calling
+     *
      * @param sampleRate sampleRate
-     * @param channels channels
+     * @param channels   channel layout
      * @return AudioTrack
      */
-    public AudioTrack createAudioTrack(int sampleRate, int channels){
+    public AudioTrack createAudioTrack(int sampleRate, int channels) {
         int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
         int channelConfig;
-        if(channels == 1){
+        if (channels == 1) {
             channelConfig = AudioFormat.CHANNEL_OUT_MONO;
-        }else if(channels == 2){
+        } else if (channels == 2) {
             channelConfig = AudioFormat.CHANNEL_OUT_STEREO;
-        }else{
+        } else {
             channelConfig = AudioFormat.CHANNEL_OUT_STEREO;
         }