The difference of two timestamps referenced to different clocks is a random number...

The difference of two timestamps referenced to different clocks is a random number & not useful input to the average frame size computation. This major brain-o would occasionally cause huge average frame times which, when later used to compute the SCR correction, would result in large gaps in the audio and/or video streams. Fixed by always computing the average frame size from the scr-corrected timestamps.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@1698 b64f7644-9d1e-0410-96f1-a4d463321fa5