[FragmentLoader] Add com.pivotshare.hls.loader.FragmentLoader

Author: hparra

src/com/pivotshare/hls/loader/FragmentLoader.as

@@ -148,6 +148,23 @@ package com.pivotshare.hls.loader {
  private var _fragLoadStatus : int;
  private var _fragSkipping : Boolean;
 
+ /*
+ * Whether _onDemuxProgress event listener has been called at least once
+ * for current Fragment.
+ */
+ private var _hasDemuxProgressedOnce : Boolean;
+
+ /*
+ * Emergency Fragment to be loaded if current Fragment does not start
+ * with an IDR.
+ */
+ private var _emergencyFragment : Fragment;
+
+ /*
+ * FragmentDemuxedStream to for emergency Fragment.
+ */
+ private var _emergencyFragmentDemuxedStream : FragmentDemuxedStream;
+
  //
  //
  //
@@ -182,6 +199,10 @@ package com.pivotshare.hls.loader {
  _loadingState = LOADING_STOPPED;
  _manifestJustLoaded = false;
  _keyLoader = new KeyLoader();
+
+ _hasDemuxProgressedOnce = false;
+ _emergencyFragment = null;
+ _emergencyFragmentDemuxedStream = null;
  };
 
  /**
@@ -1028,8 +1049,57 @@ package com.pivotshare.hls.loader {
  HLSSettings.startFromBitrate !== -1 ||
  _levels.length == 1;
 
+ var previousLevel : int = _fragPrevious !== null ? _fragPrevious.level : _fragCurrent.level;
+
+ var mustRecoverFromNonIDRStart : Boolean =
+ HLSSettings.recoverFromNonIDRStartFragment &&
+ !_fragCurrent.data.starts_with_idr &&
+ _fragCurrent.level !== previousLevel; // TODO
+
+ // If this is the first Progress call for this Fragment
+ if (!_hasDemuxProgressedOnce) {
+
+ _hasDemuxProgressedOnce = true;
+
+ CONFIG::LOGGING {
+ Log.debug2("FragmentLoader#_onDemuxProgress: Fragment[" +
+ _fragCurrent.level + "][" + _fragCurrent.seqnum +
+ "] starts with IDR? " + _fragCurrent.data.starts_with_idr +
+ "@" + _fragCurrent.data.pts_min_video_header);
+ }
+
+ //
+ // Check for IDR at beginning of Fragment on Level switch
+ //
+ // If Fragment does not start with IDR then async stream same
+ // sequence at previous Level.
+ //
+ if (mustRecoverFromNonIDRStart) {
+
+ CONFIG::LOGGING {
+ Log.debug("FragmentLoader#_onDemuxProgress: Fragment["
+ + _fragCurrent.level + "][" + _fragCurrent.seqnum +
+ "] DOES NOT start with IDR! Will load same sequence at previous level to recover.");
+ }
+
+ _emergencyFragment = _levels[previousLevel].getFragmentfromSeqNum(_fragCurrent.seqnum);
+
+ // Initiate loading of same seqnum Fragment on previous level to find IDR
+ _keyLoader.load(_emergencyFragment.decrypt_url, function (err : HLSError, keyData : ByteArray) : void {
+ _emergencyFragmentDemuxedStream = new FragmentDemuxedStream(_hls.stage);
+ _emergencyFragmentDemuxedStream.load(_emergencyFragment, keyData, null);
+ });
+ }
+ }
+
+ //
+ // TODO: We have temporarily disabled progressive buffering, as it
+ // does not seem to work with IDR recovery. Seems PTS analysis
+ // changes expected states. Needs to be debugged further.
+ //
+ /*
  // Determine if we can do progressively append to StreamBuffer
- if (_fragmentFirstLoaded || (_manifestJustLoaded && isFirstFragmentLevelDefined)) {
+ if (!mustRecoverFromNonIDRStart && (_fragmentFirstLoaded || (_manifestJustLoaded && isFirstFragmentLevelDefined))) {
 
  //
  // if audio expected, PTS analysis is done on audio
@@ -1129,7 +1199,7 @@ package com.pivotshare.hls.loader {
  _hasDiscontinuity = false;
  }
  }
-
+ */
  }
 
  /**
@@ -1175,6 +1245,50 @@ package com.pivotshare.hls.loader {
  }
  }
 
+ //
+ // Handle possible IDR Problem here
+ // TODO: We should still have have simple removal of frames as option
+ //
+ if (_emergencyFragment) {
+
+ _emergencyFragment = _emergencyFragmentDemuxedStream.getFragment();
+
+ // Return all tags (audio/video) unless it is Video tag that precedes IDR
+ var isNotBadVideoTag : Function = function (tag:FLVTag, index:int, vector:Vector.<FLVTag>):Boolean {
+ return tag.type !== FLVTag.AVC_NALU || tag.pts >= _fragCurrent.data.pts_min_video_header;
+ }
+
+ // Return only Video tags that precede and IDR
+ var isGoodVideoTag : Function = function (tag:FLVTag, index:int, vector:Vector.<FLVTag>):Boolean {
+ return tag.type == FLVTag.AVC_NALU && tag.pts < _fragCurrent.data.pts_min_video_header;
+ }
+
+ // It's already been found
+ if (!isNaN(_emergencyFragment.data.pts_min_video_header)) {
+ CONFIG::LOGGING {
+ Log.debug("FragmentLoader#_fragParsingCompleteHandler: Will fix non-IDR right now!");
+ }
+
+ var tagsExceptBadVideo : Vector.<FLVTag> = _fragCurrent.data.tags.filter(isNotBadVideoTag);
+ var goodNonIDRTags : Vector.<FLVTag> = _emergencyFragment.data.tags.filter(isGoodVideoTag);
+
+ _fragCurrent.data.tags = goodNonIDRTags.concat(tagsExceptBadVideo);
+
+ _emergencyFragment = null;
+ // TODO: Remove listener?
+ _emergencyFragmentDemuxedStream.close();
+ _emergencyFragmentDemuxedStream.removeEventListener(Event.COMPLETE, _onEmergencyDemuxedStreamComplete);
+ _emergencyFragmentDemuxedStream = null;
+
+ } else { // bail leaving _emergencyFragment callback to recall this callback :(
+ CONFIG::LOGGING {
+ Log.debug("FragmentLoader#_fragParsingCompleteHandler: Cannot fix this non-IDR Fragment yet.");
+ }
+ _emergencyFragmentDemuxedStream.addEventListener(Event.COMPLETE, _onEmergencyDemuxedStreamComplete);
+ return;
+ }
+ }
+
  //
  // Finish calculating processing metrics
  // TODO: What else should this include, e.g. fragment fixing?
@@ -1282,6 +1396,9 @@ package com.pivotshare.hls.loader {
  _hls.dispatchEvent(new HLSEvent(HLSEvent.TAGS_LOADED, _metrics));
  _fragCurrent.data.shiftTags();
  _hasDiscontinuity = false;
+
+ _hasDemuxProgressedOnce = false;
+ _emergencyFragment = null;
  }
 
  } else {
@@ -1350,5 +1467,16 @@ package com.pivotshare.hls.loader {
  private function _onDemuxID3TagFound(id3_tags : Vector.<ID3Tag>) : void {
  _fragCurrent.data.id3_tags = id3_tags;
  }
+
+ /**
+ * Called when emergency Fragment has finished loading and demuxing.
+ *
+ * @method _onEmergencyDemuxedStreamComplete
+ * @param {Event} evt
+ */
+ private function _onEmergencyDemuxedStreamComplete (evt : Event) : void {
+ _emergencyFragment = _emergencyFragmentDemuxedStream.getFragment();
+ _onDemuxComplete();
+ }
  }
 }