[mythtv-users] Mac OS X choppy playback at high display resolutions, such as 1080p

MythTV mythtv at taoyama.com
Wed Oct 10 02:25:57 UTC 2007


Try this simple patch without the previous patch.

What I think is happening is that in order to keep the line count a  
multiple of 16 the video height is being set to 1088 but the actual  
content is 1080.  When this happens the pixel aspect ratio difference  
becomes 0.013 which causes a transform matrix to be created so  
Quicktime will try to "transform" the image to maintain the aspect  
ratio.  By allowing a 0.015 difference in pixel aspect ratio to be  
ignored it should remove the need for the transform.

After a very quick test it seems to work for me.

Let me know if this fixes the problem for you.


Index: videoout_quartz.cpp
--- videoout_quartz.cpp (revision 14063)
+++ videoout_quartz.cpp (working copy)
@@ -307,7 +307,7 @@

      // scale for non-square pixels
-    if (fabsf(aspect - (sw * 1.0 / sh)) > 0.01)
+    if (fabsf(aspect - (sw * 1.0 / sh)) > 0.015)
          if (parentData->scaleUpVideo)

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