         
         // リーダーが空の場合、まず先頭のアセットを読み込む
         if _readers.isEmpty && startIndex < _assets.count {
-            if let assetreader = AssetReaderFragment(asset:_assets[startIndex].asset,
+            if let assetreader = _createFragment(_assets[startIndex].asset,
                 rate:_playbackRate, startTime:startTime)
             {
                 startTime = kCMTimeZero
                 _readers.append(assetreader)
             } else {
-                NSLog("(1) Failed to instantiate a reader of [\((_assets[startIndex].asset as? AVURLAsset)?.URL.lastPathComponent?)]")
+                _assets.removeAtIndex(startIndex)
             }
         }
 

                me._assets.removeAtIndex(failedIndex!)
            }
        }
    }
}


                            break outer
                        }

                        if let assetreader = me._createFragment(target.asset,
                            rate:me._playbackRate, startTime:startTime)
                        {
                            startTime = kCMTimeZero
                            me._readers.append(assetreader)
                        } else {
                            // 再度作成しようとしても使えないので、取り除く
                            failedIndex = actualIndex+1+j
                            break outer
