diff --git a/library-push/src/main/java/com/yinuo/library/vlc/encoder/AndroidMuxer.java b/library-push/src/main/java/com/yinuo/library/vlc/encoder/AndroidMuxer.java
index a65fdd9..e038a1b 100644
--- a/library-push/src/main/java/com/yinuo/library/vlc/encoder/AndroidMuxer.java
+++ b/library-push/src/main/java/com/yinuo/library/vlc/encoder/AndroidMuxer.java
@@ -62,6 +62,10 @@ public class AndroidMuxer {
             throw new IllegalStateException();
         }
 
+        if (mMuxer == null) {
+            throw new IllegalStateException("mMuxer is null");
+        }
+
         synchronized (mMuxer) {
             int track = mMuxer.addTrack(trackFormat);
             mVideoFormat = trackFormat;
@@ -79,7 +83,7 @@ public class AndroidMuxer {
     }
 
     public void writeSampleData(int trackIndex, ByteBuffer encodedData, MediaCodec.BufferInfo bufferInfo) {
-        if (mNumReleases != 0) {
+        if (mNumReleases != 0 || mMuxer == null) {
             return;
         }
         synchronized (mMuxer) {
@@ -101,20 +105,24 @@ public class AndroidMuxer {
     }
 
     public boolean release() {
-        synchronized (mMuxer) {
-            if (++mNumReleases == mNumTracks) {
-                stopMuxer();
-                return true;
+        if (mMuxer != null) {
+            synchronized (mMuxer) {
+                if (++mNumReleases == mNumTracks) {
+                    stopMuxer();
+                    return true;
+                }
             }
         }
         return false;
     }
 
     public void stopMuxer() {
-        mMuxer.stop();
-        mMuxer.release();
-        if (mStartRecordTime > 0 && mStartRecordTime < System.currentTimeMillis() && !TextUtils.isEmpty(mCurrentPath)) {
-            insertToDB(mStartRecordTime, mCurrentPath);
+        if (mMuxer != null) {
+            mMuxer.stop();
+            mMuxer.release();
+            if (mStartRecordTime > 0 && mStartRecordTime < System.currentTimeMillis() && !TextUtils.isEmpty(mCurrentPath)) {
+                insertToDB(mStartRecordTime, mCurrentPath);
+            }
         }
     }
 }
diff --git a/library-push/src/main/java/com/yinuo/library/vlc/encoder/MediaCodecManager.java b/library-push/src/main/java/com/yinuo/library/vlc/encoder/MediaCodecManager.java
index 9065ab8..11115f7 100644
--- a/library-push/src/main/java/com/yinuo/library/vlc/encoder/MediaCodecManager.java
+++ b/library-push/src/main/java/com/yinuo/library/vlc/encoder/MediaCodecManager.java
@@ -287,8 +287,12 @@ public class MediaCodecManager {
 
                 @Override
                 public void onOutputFormatChanged(@NonNull MediaCodec codec, @NonNull MediaFormat format) {
-                    MediaFormat newFormat = mMediaCodec.getOutputFormat();
-                    mTrackIndex = androidMuxer.addTrack(newFormat);
+                    try {
+                        MediaFormat newFormat = mMediaCodec.getOutputFormat();
+                        mTrackIndex = androidMuxer.addTrack(newFormat);
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
                 }
             }, mHandler);
             mMediaCodec.start();