There is an operand size mismatch in the EVR 'PresentImage()' callback parameters from dshowhelper to MP affecting the aspect ratio values - in some places these are declared as 32-bit signed and in others as 16-bit signed...

Most of the time the values are less than 32767, but the bug meanes that larger values get truncated so the aspect ratio is completely wrong....the result is no video plays in this situation.

h4. Steps to Reproduce
Just play a file with large enough aspect ratio numbers....

h4. Additional Information
Reported by user here - http://forum.team-mediaportal.com/codecs-external-players-55/black-screen-some-h-264-codec-renderer-problem-99386/

I created a modified dshowhelper which ensures that the values passed to MP cannot exceed 32768, and user reports problem is fixed. I suggest this is added to the trunk dshowhelper code for now, but the operand sizes should be fixed properly for MP 1.3.0 ?