From 075756d64635101a6889af14054ae152e5f08fcd Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Mon, 5 Nov 2018 16:44:24 +0100
Subject: [PATCH] Improved output timing

---
 src/output/output.cpp | 28 ++++++++++++++++++++++------
 src/output/output.h   |  2 ++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/output/output.cpp b/src/output/output.cpp
index 137e7f01..a182207b 100644
--- a/src/output/output.cpp
+++ b/src/output/output.cpp
@@ -64,6 +64,7 @@ namespace Mist{
     isInitialized = false;
     isBlocking = false;
     needsLookAhead = 0;
+    extraKeepAway = 0;
     lastStats = 0;
     maxSkipAhead = 7500;
     realTime = 1000;
@@ -522,7 +523,7 @@ namespace Mist{
         nxtKeyNum[trackId] = 0;
       }
       stats(true);
-      Util::wait(100);
+      playbackSleep(100);
       pageNum = pageNumForKey(trackId, keyNum);
     }
     
@@ -752,7 +753,7 @@ namespace Mist{
             continue;
           }//ignore missing tracks
           DTSC::Track & thisTrack = myMeta.tracks[*ti];
-          if (thisTrack.lastms < seekPos+needsLookAhead+thisTrack.minKeepAway){good = false; break;}
+          if (thisTrack.lastms < seekPos+needsLookAhead+extraKeepAway+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);
@@ -786,6 +787,16 @@ namespace Mist{
       }
     }
   }
+
+  /// Waits for the given amount of millis, increasing the realtime playback
+  /// related times as needed to keep smooth playback intact.
+  void Output::playbackSleep(uint64_t millis){
+    if (realTime){
+      firstTime += millis;
+      extraKeepAway += millis;
+    }
+    Util::wait(millis);
+  }
  
   int Output::run(){
     DONTEVEN_MSG("MistOut client handler started");
@@ -821,7 +832,8 @@ namespace Mist{
               uint32_t sleepTime = std::min((uint32_t)250, needsLookAhead);
               //wait at most double the look ahead time, plus ten seconds
               uint32_t timeoutTries = (needsLookAhead / sleepTime) * 2 + (10000/sleepTime);
-              uint64_t needsTime = thisPacket.getTime() + needsLookAhead; 
+              uint64_t needsTime = thisPacket.getTime() + needsLookAhead;
+              bool firstTime = true;
               while(--timeoutTries && keepGoing()){
                 bool lookReady = true;
                 for (std::set<long unsigned int>::iterator it = selectedTracks.begin(); it != selectedTracks.end(); it++){
@@ -834,7 +846,11 @@ namespace Mist{
                   }
                 }
                 if (lookReady){break;}
-                Util::wait(sleepTime);
+                if (firstTime){
+                  firstTime = false;
+                }else{
+                  playbackSleep(sleepTime);
+                }
                 stats();
                 updateMeta();
               }
@@ -986,7 +1002,7 @@ namespace Mist{
       //VoD might be slow, so we check VoD case also, just in case
       if (currKeyOpen.count(nxt.tid) && (currKeyOpen[nxt.tid] == (unsigned int)nextPage || nextPage == -1)){
         if (++emptyCount < 100){
-          Util::wait(250);
+          playbackSleep(250);
           //we're waiting for new data to show up
           if (emptyCount % 64 == 0){
             reconnect();//reconnect every 16 seconds
@@ -1073,7 +1089,7 @@ namespace Mist{
       while(myMeta.live && counter < 40 && myMeta.tracks[nxt.tid].getKey(nxtKeyNum[nxt.tid]).getTime() != thisPacket.getTime()){
         if (counter++){
           //Only sleep 250ms if this is not the first updatemeta try
-          Util::wait(250);
+          playbackSleep(250);
         }
         updateMeta();
         nxtKeyNum[nxt.tid] = getKeyForTime(nxt.tid, thisPacket.getTime());
diff --git a/src/output/output.h b/src/output/output.h
index 21391cd7..cd83b61b 100644
--- a/src/output/output.h
+++ b/src/output/output.h
@@ -76,6 +76,7 @@ namespace Mist {
       virtual void onFail();
       virtual void requestHandler();
       static Util::Config * config;
+      void playbackSleep(uint64_t millis);
     private://these *should* not be messed with in child classes.
       std::map<unsigned long, unsigned int> currKeyOpen;
       void loadPageForKey(long unsigned int trackId, long long int keyNum);
@@ -90,6 +91,7 @@ namespace Mist {
       std::string UA; ///< User Agent string, if known.
       uint16_t uaDelay;///<Seconds to wait before setting the UA.
       uint64_t lastRecv;
+      uint64_t extraKeepAway;
       long long unsigned int firstTime;///< Time of first packet after last seek. Used for real-time sending.
       virtual std::string getConnectedHost();
       virtual std::string getConnectedBinHost();