diff --git a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/CacheManagingDrawTask.java b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/CacheManagingDrawTask.java
index 154ac72e..886acb0c 100644
--- a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/CacheManagingDrawTask.java
+++ b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/CacheManagingDrawTask.java
@@ -77,6 +77,19 @@ public void addDanmaku(BaseDanmaku danmaku) {
         mCacheManager.addDanmaku(danmaku);
     }
 
+    @Override
+    protected void onDanmakuRemoved(BaseDanmaku danmaku) {
+        super.onDanmakuRemoved(danmaku);
+        if (danmaku.hasDrawingCache()) {
+            if (danmaku.cache.hasReferences()) {
+                danmaku.cache.decreaseReference();
+            } else {
+                danmaku.cache.destroy();
+            }
+            danmaku.cache = null;
+        }
+    }
+
     @Override
     public RenderingState draw(AbsDisplayer<?> displayer) {
         RenderingState result = super.draw(displayer);
@@ -178,7 +191,14 @@ public void seek(long mills) {
 
         public void addDanmaku(BaseDanmaku danmaku) {
             if (mHandler != null) {
-                mHandler.obtainMessage(CacheHandler.ADD_DANMAKKU, danmaku).sendToTarget();
+                if (danmaku.isLive) {
+                    if (danmaku.isTimeOut()) {
+                        return;
+                    }
+                    mHandler.createCache(danmaku);
+                } else {
+                    mHandler.obtainMessage(CacheHandler.ADD_DANMAKKU, danmaku).sendToTarget();
+                }
             }
         }
 
@@ -450,19 +470,7 @@ public void handleMessage(Message msg) {
                         break;
                     case ADD_DANMAKKU:
                         BaseDanmaku item = (BaseDanmaku) msg.obj;
-                        if (item.isTimeOut()) {
-                            break;
-                        }
-                        if (item.priority == 0 && item.isFiltered()) {
-                            break;
-                        }
-                        if (!item.hasDrawingCache()) {
-                            buildCache(item);
-                        }
-                        if (item.isLive) {
-                            mCacheTimer.update(mTimer.currMillisecond
-                                    + DanmakuFactory.MAX_DANMAKU_DURATION * mScreenSize);
-                        }
+                        addDanmakuAndBuildCache(item);
                         break;
                     case CLEAR_TIMEOUT_CACHES:
                         clearTimeOutCaches();
@@ -560,12 +568,16 @@ private long prepareCaches(boolean repositioned) {
                 synchronized (danmakuList) {
                     danmakus = danmakuList.subnew(curr, end);
                 }
-                if (danmakus == null || danmakus.isEmpty()) {
+                if (danmakus == null) {
                     mCacheTimer.update(end);
                     return 0;
                 }
                 BaseDanmaku first = danmakus.first();
                 BaseDanmaku last = danmakus.last();
+                if (first == null || last == null) {
+                    mCacheTimer.update(end);
+                    return 0;
+                }
                 long deltaTime = first.time - mTimer.currMillisecond;
                 long sleepTime = 30 + 10 * deltaTime / DanmakuFactory.MAX_DANMAKU_DURATION;
                 sleepTime = Math.min(100, sleepTime);
@@ -657,6 +669,34 @@ private long prepareCaches(boolean repositioned) {
                 return consumingTime;
             }
 
+            public boolean createCache(BaseDanmaku item) {
+                // measure
+                if (!item.isMeasured()) {
+                    item.measure(mDisp);
+                }
+                DrawingCache cache = null;
+                try {
+                    cache = mCachePool.acquire();
+                    cache = DanmakuUtils.buildDanmakuDrawingCache(item, mDisp, cache);
+                    item.cache = cache;
+                } catch (OutOfMemoryError e) {
+//Log.e("cache", "break at error: oom");
+                    if (cache != null) {
+                        mCachePool.release(cache);
+                    }
+                    item.cache = null;
+                    return false;
+                } catch (Exception e) {
+//Log.e("cache", "break at exception:" + e.getMessage());
+                    if (cache != null) {
+                        mCachePool.release(cache);
+                    }
+                    item.cache = null;
+                    return false;
+                }
+                return true;
+            }
+
             private byte buildCache(BaseDanmaku item) {
                 
                 // measure
@@ -721,6 +761,25 @@ private byte buildCache(BaseDanmaku item) {
                 }
             }
 
+            private final void addDanmakuAndBuildCache(BaseDanmaku danmaku) {
+                if (danmaku.isTimeOut()) {
+                    return;
+                }
+                if (danmaku.priority == 0 && danmaku.isFiltered()) {
+                    return;
+                }
+                if (!danmaku.isLive && danmaku.isLate() && danmaku.time > mCacheTimer.currMillisecond + DanmakuFactory.MAX_DANMAKU_DURATION) {
+                    return;
+                }
+                if (!danmaku.hasDrawingCache()) {
+                    buildCache(danmaku);
+                }
+                if (danmaku.isLive) {
+                    mCacheTimer.update(mTimer.currMillisecond
+                            + DanmakuFactory.MAX_DANMAKU_DURATION * mScreenSize);
+                }
+            }
+
             public void begin() {
                 sendEmptyMessage(PREPARE);
                 sendEmptyMessageDelayed(CLEAR_TIMEOUT_CACHES, DanmakuFactory.MAX_DANMAKU_DURATION);
diff --git a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/DrawTask.java b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/DrawTask.java
index dee8deb4..8ff9be40 100644
--- a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/DrawTask.java
+++ b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/controller/DrawTask.java
@@ -123,6 +123,10 @@ public synchronized void removeAllDanmakus() {
         danmakuList.clear();
     }
 
+    protected void onDanmakuRemoved(BaseDanmaku danmaku) {
+        // TODO call callback here
+    }
+
     @Override
     public synchronized void removeAllLiveDanmakus() {
         if (danmakus == null || danmakus.isEmpty())
@@ -130,8 +134,10 @@ public synchronized void removeAllLiveDanmakus() {
         synchronized (danmakus) {
             IDanmakuIterator it = danmakus.iterator();
             while (it.hasNext()) {
-                if (it.next().isLive) {
+                BaseDanmaku danmaku = it.next();
+                if (danmaku.isLive) {
                     it.remove();
+                    onDanmakuRemoved(danmaku);
                 }
             }
         }
@@ -142,13 +148,12 @@ protected synchronized void removeUnusedLiveDanmakusIn(int msec) {
             return;
         long startTime = System.currentTimeMillis();
         IDanmakuIterator it = danmakuList.iterator();
-        int count = 0;
         while (it.hasNext()) {
             BaseDanmaku danmaku = it.next();
             boolean isTimeout = danmaku.isTimeOut();
             if (isTimeout && danmaku.isLive) {
                 it.remove();
-                count++;
+                onDanmakuRemoved(danmaku);
             }
             if (!isTimeout || System.currentTimeMillis() - startTime > msec) {
                 break;
diff --git a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/danmaku/model/android/Danmakus.java b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/danmaku/model/android/Danmakus.java
index dd3fa4f4..ac364ad9 100644
--- a/DanmakuFlameMaster/src/main/java/master/flame/danmaku/danmaku/model/android/Danmakus.java
+++ b/DanmakuFlameMaster/src/main/java/master/flame/danmaku/danmaku/model/android/Danmakus.java
@@ -178,7 +178,7 @@ private Collection<BaseDanmaku> subset(long startTime, long endTime) {
     @Override
     public IDanmakus subnew(long startTime, long endTime) {
         Collection<BaseDanmaku> subset = subset(startTime, endTime);
-        if (subset == null) {
+        if (subset == null || subset.isEmpty()) {
             return null;
         }
         ArrayList<BaseDanmaku> newSet = new ArrayList<BaseDanmaku>(subset);