Index: mythtv/libs/libmythtv/NuppelVideoPlayer.cpp
===================================================================
--- mythtv/libs/libmythtv/NuppelVideoPlayer.cpp	(revision 22730)
+++ mythtv/libs/libmythtv/NuppelVideoPlayer.cpp	(working copy)
@@ -1074,13 +1074,17 @@
 
     m_scan_locked = (scan != kScan_Detect);
 
-    if (scan == m_scan)
+    if (scan == m_scan) {
+        bool interlaced = m_deint_possible && is_interlaced(scan);
+        videosync->SetFrameInterval(frame_interval, interlaced);
         return;
+    }
 
     bool interlaced = is_interlaced(scan);
     if (interlaced && !m_deint_possible)
     {
         m_scan = scan;
+        videosync->SetFrameInterval(frame_interval, false);
         return;
     }
 
@@ -1114,11 +1118,8 @@
         if (kScan_Progressive == scan)
         {
             m_double_process = false;
-            if (m_double_framerate)
-            {
-                m_double_framerate = false;
-                videosync->SetFrameInterval(frame_interval, false);
-            }
+            m_double_framerate = false;
+            videosync->SetFrameInterval(frame_interval, false);
             videoOutput->SetDeinterlacingEnabled(false);
             VERBOSE(VB_PLAYBACK, "Disabled deinterlacing");
         }
Index: mythtv/libs/libmythtv/vsync.cpp
===================================================================
--- mythtv/libs/libmythtv/vsync.cpp	(revision 22730)
+++ mythtv/libs/libmythtv/vsync.cpp	(working copy)
@@ -197,25 +197,15 @@
 {
     struct timeval now;
     gettimeofday(&now, NULL);
-    //cout << "CalcDelay: next: " << timeval_str(m_nexttrigger) << " now " 
-    // << timeval_str(now) << endl;
         
     int ret_val = (m_nexttrigger.tv_sec - now.tv_sec) * 1000000 +
                   (m_nexttrigger.tv_usec - now.tv_usec);
 
-    //cout << "delay " << ret_val << endl;
-
-    if (ret_val > m_frame_interval * 2)
-    {
-        if (m_interlaced)
-            ret_val = m_frame_interval; // same as / 2 * 2.
-        else
-            ret_val = m_frame_interval * 2;
-
-        // set nexttrigger to our new target time
+    // We don't want to allow too much underflow. If
+    // the trigger time is too far in the past, reset it now.
+    if (ret_val < -m_frame_interval / 2) {
         m_nexttrigger.tv_sec = now.tv_sec;
         m_nexttrigger.tv_usec = now.tv_usec;
-        OffsetTimeval(m_nexttrigger, ret_val);
     }
 
     return ret_val;