Added minKeepAway support to DTSC::Track object, senders and parsers

src/output/output.cpp

@@ -786,6 +786,53 @@ namespace Mist{
     seek(seekPos);
   }
 
+  /// This function attempts to forward playback in live streams to a more live point.
+  /// It seeks to the last sync'ed keyframe of the main track, no closer than needsLookAhead+minKeepAway ms from the end.
+  /// Aborts if not live, there is no main track or it has no keyframes.
+  bool Output::liveSeek(){
+    unsigned long long seekPos = 0;
+    if (!myMeta.live){return false;}
+    long unsigned int mainTrack = getMainSelectedTrack();
+    //cancel if there are no keys in the main track
+    if (!myMeta.tracks.count(mainTrack)){return false;}
+    DTSC::Track & mainTrk = myMeta.tracks[mainTrack];
+    if (!mainTrk.keys.size()){return false;}
+    uint32_t minKeepAway = mainTrk.minKeepAway;
+
+    //Only skip forward if we can win at least 500ms
+    if (thisPacket.getTime() + 500 > mainTrk.keys.rbegin()->getTime()){
+      return false;
+    }
+
+    for (std::deque<DTSC::Key>::reverse_iterator it = myMeta.tracks[mainTrack].keys.rbegin(); it != myMeta.tracks[mainTrack].keys.rend(); ++it){
+      seekPos = it->getTime();
+      if(seekPos <= thisPacket.getTime()){return false;}
+      bool good = true;
+      //check if all tracks have data for this point in time
+      for (std::set<unsigned long>::iterator ti = selectedTracks.begin(); ti != selectedTracks.end(); ++ti){
+        if (!myMeta.tracks.count(*ti)){
+          HIGH_MSG("Skipping track %lu, not in tracks", *ti);
+          continue;
+        }//ignore missing tracks
+        DTSC::Track & thisTrack = myMeta.tracks[*ti];
+        if (thisTrack.lastms < seekPos+needsLookAhead+thisTrack.minKeepAway){good = false; break;}
+        if (mainTrack == *ti){continue;}//skip self
+        if (thisTrack.lastms == thisTrack.firstms){
+          HIGH_MSG("Skipping track %lu, last equals first", *ti);
+          continue;
+        }//ignore point-tracks
+        HIGH_MSG("Track %lu is good", *ti);
+      }
+      //if yes, seek here
+      if (good){
+        INFO_MSG("Skipping forward %llums (%u ms LA, %lu ms mKA)", seekPos - thisPacket.getTime(), needsLookAhead, mainTrk.minKeepAway);
+        seek(seekPos);
+        return true;
+      }
+    }
+    return false;
+  }
+
   void Output::requestHandler(){
     static bool firstData = true;//only the first time, we call onRequest if there's data buffered already.
     if ((firstData && myConn.Received().size()) || myConn.spool()){

src/output/output.h

@@ -69,6 +69,7 @@ namespace Mist {
       virtual void onRequest();
       static void listener(Util::Config & conf, int (*callback)(Socket::Connection & S));
       virtual void initialSeek();
+      virtual bool liveSeek();
       virtual bool onFinish() {
         return false;
       }

src/output/output_progressive_mp4.cpp

@@ -925,16 +925,8 @@ namespace Mist {
     if (myMeta.live) {
       //if header needed
       if (!partListLength || partListSent >= partListLength) {
-        DTSC::Track & mainTrk = myMeta.tracks[vidTrack];
+        if (fragSeqNum > 10){
-        // The extra 2000ms here is for the metadata sync delay.
+          if (liveSeek()){return;}
-        // It can be removed once we get rid of that.
-        // (sync delay = ~1s, minimum lookAhead is 420ms -> ~600ms extra needed, we use 2000ms to be safe)
-        if (myMeta.sourceURI.find("http://") == std::string::npos || myMeta.sourceURI.find(".m3u") == std::string::npos){
-          if (fragSeqNum > 10 && thisPacket.getTime() + needsLookAhead + 2000 < mainTrk.keys.rbegin()->getTime() && mainTrk.lastms - mainTrk.keys.rbegin()->getTime() > needsLookAhead){
-            INFO_MSG("Skipping forward %llums (%u ms LA)", mainTrk.keys.rbegin()->getTime() - thisPacket.getTime(), needsLookAhead);
-            seek(mainTrk.keys.rbegin()->getTime());
-            return;
-          }
         }
         //building set first
         buildFragment();//map with metadata for keyframe

src/output/output_rtsp.cpp

@@ -108,16 +108,7 @@ namespace Mist{
     if (myMeta.live && lastTimeSync + 666 < timestamp){
       lastTimeSync = timestamp;
       updateMeta();
-      DTSC::Track &mainTrk = myMeta.tracks[getMainSelectedTrack()];
+      if (liveSeek()){return;}
-      // The extra 2000ms here is for the metadata sync delay.
-      // It can be removed once we get rid of that.
-      if (timestamp + 2000 + needsLookAhead < mainTrk.keys.rbegin()->getTime() &&
-          mainTrk.lastms - mainTrk.keys.rbegin()->getTime() > needsLookAhead){
-        INFO_MSG("Skipping forward %llums (%llu ms LA)",
-                 mainTrk.keys.rbegin()->getTime() - thisPacket.getTime(), needsLookAhead);
-        seek(mainTrk.keys.rbegin()->getTime());
-        return;
-      }
     }
 
     void *socket = 0;