diff --git a/app/src/main/java/net/ossrs/sea/SrsEncoder.java b/app/src/main/java/net/ossrs/sea/SrsEncoder.java
index bbaec0c..19e7106 100644
--- a/app/src/main/java/net/ossrs/sea/SrsEncoder.java
+++ b/app/src/main/java/net/ossrs/sea/SrsEncoder.java
@@ -70,12 +70,13 @@ public class SrsEncoder {
 
     public int start() {
         try {
-            muxer.start(rtmpUrl, VCROP_WIDTH, VCROP_HEIGHT);
+            muxer.start(rtmpUrl);
         } catch (IOException e) {
             Log.e(TAG, "start muxer failed.");
             e.printStackTrace();
             return -1;
         }
+        muxer.setVideoResolution(VCROP_WIDTH, VCROP_HEIGHT);
 
         // the referent PTS for video and audio encoder.
         mPresentTimeUs = System.nanoTime() / 1000;
diff --git a/app/src/main/java/net/ossrs/sea/SrsFlvMuxer.java b/app/src/main/java/net/ossrs/sea/SrsFlvMuxer.java
index 489b49d..6464fc6 100644
--- a/app/src/main/java/net/ossrs/sea/SrsFlvMuxer.java
+++ b/app/src/main/java/net/ossrs/sea/SrsFlvMuxer.java
@@ -4,14 +4,14 @@ import android.media.MediaCodec;
 import android.media.MediaFormat;
 import android.util.Log;
 
-import net.ossrs.sea.rtmp.RtmpPublisher;
-
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import net.ossrs.sea.rtmp.RtmpPublisher;
+
 /**
  * Created by winlin on 5/2/15.
  * Updated by leoma on 4/1/16.
@@ -74,7 +74,18 @@ public class SrsFlvMuxer {
      * get cached video frame number in publisher
      */
     public final AtomicInteger getVideoFrameCacheNumber() {
-        return publisher.getVideoFrameCacheNumber();
+        return publisher == null ? null : publisher.getVideoFrameCacheNumber();
+    }
+
+    /**
+     * set video resolution for publisher
+     * @param width
+     * @param height
+     */
+    public void setVideoResolution(int width, int height) {
+        if (publisher != null) {
+            publisher.setVideoResolution(width, height);
+        }
     }
 
     /**
@@ -134,9 +145,8 @@ public class SrsFlvMuxer {
     /**
      * start to the remote SRS for remux.
      */
-    public void start(String url, int width, int height) throws IOException {
+    public void start(String url) throws IOException {
         rtmpUrl = url;
-        publisher.setVideoResolution(width, height);
 
         worker = new Thread(new Runnable() {
             @Override
diff --git a/app/src/main/java/net/ossrs/sea/rtmp/io/WriteThread.java b/app/src/main/java/net/ossrs/sea/rtmp/io/WriteThread.java
index da83d9c..4f1e570 100644
--- a/app/src/main/java/net/ossrs/sea/rtmp/io/WriteThread.java
+++ b/app/src/main/java/net/ossrs/sea/rtmp/io/WriteThread.java
@@ -22,7 +22,6 @@ public class WriteThread extends Thread {
 
     private static final String TAG = "WriteThread";
 
-    private RtmpPublisher.EventHandler handler;
     private RtmpSessionInfo rtmpSessionInfo;
     private OutputStream out;
     private ConcurrentLinkedQueue<RtmpPacket> writeQueue = new ConcurrentLinkedQueue<RtmpPacket>();