                     _fragMainIdx++;
                     // compute sliding if needed
                     if(computeSliding) {
-                        // if -1 : it is not the first appending for this fragment type : we can compute playlist sliding
+                        // if not -1 : it is not the first appending for this fragment type : we can compute playlist sliding
                         if(_nextExpectedAbsoluteStartPosMain !=-1) {
                             // if same continuity counter, sliding can be computed using PTS, it will be more accurate
                             if(continuity == _fragMainInitialContinuity) {

                            _fragAltAudioInitialPTS = min_pts;
                            _fragAltAudioInitialContinuity = continuity;
                        }
                        _nextExpectedAbsoluteStartPosAltAudio = nextRelativeStartPos + sliding;
                    }
                    CONFIG::LOGGING {
                        Log.debug('new altaudio frag,start/sliding/idx:' + startPosition + '/' + sliding + '/' + _fragAltAudioIdx);
                    }
                }
                fragIdx = _fragAltAudioIdx;
            }

            for each (var tag : FLVTag in tags) {

                                }
                            } else {
                                sliding = _liveSlidingMain = _nextExpectedAbsoluteStartPosMain - startPosition;
                                CONFIG::LOGGING {
                                   Log.debug2('sliding on different cc: expectedAbsoluteStart/relativeStart/sliding' + _nextExpectedAbsoluteStartPosMain.toFixed(3) + '/' + startPosition.toFixed(3) + '/' + sliding.toFixed(3));
                                }
                            }
                        } else {
                            _fragMainInitialStartPosition = startPosition;
                            _fragMainInitialPTS = min_pts;
                            _fragMainInitialContinuity = continuity;
                        }
                    }
                    CONFIG::LOGGING {
                        Log.debug('new main frag,start/sliding/cc/idx:' + startPosition.toFixed(3) + '/' + sliding.toFixed(3) + '/' + continuity + '/' + _fragMainIdx);
                    }
                }
                fragIdx = _fragMainIdx;
                /* update next expected absolute start pos at this point : absolute = relative + sliding
                   useful to compute sliding when discontinuity occurs
                */
                _nextExpectedAbsoluteStartPosMain = nextRelativeStartPos + sliding;
            } else {
                sliding = _liveSlidingAltAudio;
                // if a new fragment is being appended
