Comments by Mark Spieth:

"Due to the fact that refresh rate is the fundamental output timing rate, not the input rate which can be anything. The av_sync adjustment needs to be with respect to the resfresh rate and not frame interval. However, no real proof that this is any better or worse but just IMO more logically correct and consistent."

"avsync_used is the minimum of the delayed estimate and the current value of avsync (with the delay from last vsync event included). This improves lock time as the smallest value is the better one to use just in case the instantaneous value deviates from the steady state. Also speeds up initial lock time as avdel is 0 initially."

Refs #7964.

Author: tralph

mythtv/libs/libmythtv/mythplayer.cpp

@@ -1909,19 +1909,21 @@ void MythPlayer::AVSync(VideoFrame *buffer, bool limit_delay)
                 avsync_delay = 90000;
             avsync_avg = (avsync_delay + (avsync_avg * 3)) / 4;
 
+            int avsync_used = avsync_avg;
+            if (labs(avsync_used) > labs(avsync_delay))
+                avsync_used = avsync_delay;
+
             /* If the audio time codes and video diverge, shift
                the video by one interlaced field (1/2 frame) */
             if (!lastsync)
             {
-                if (avsync_avg > frame_interval * 3 / 2)
+                if (avsync_used > refreshrate)
                 {
                     avsync_adjustment += refreshrate;
-                    lastsync = true;
                 }
-                else if (avsync_avg < 0 - frame_interval * 3 / 2)
+                else if (avsync_used < 0 - refreshrate)
                 {
                     avsync_adjustment -= refreshrate;
-                    lastsync = true;
                 }
             }
             else
@@ -1932,6 +1934,10 @@ void MythPlayer::AVSync(VideoFrame *buffer, bool limit_delay)
             ResetAVSync();
         }
     }
+    else
+    {
+        VERBOSE(VB_PLAYBACK+VB_TIMESTAMP, LOC + QString("A/V no sync proc ns:%1").arg(normal_speed));
+    }
 }
 
 void MythPlayer::RefreshPauseFrame(void)