420 to 444 issue
recently found a picture quality issue that really bothers me for a while ...
i thought the CUE issue is a well known problem and every decoder should already handle 420 upsampling properly by now, but surprisingly, when i use virtualdub to load a WMV 720p HD file and the crop it to 480p file, i found the color jaggy lines! then i tried all different options but still not be able to make the tools to handle that properly in virtualdub.
data path i tried ... directly load wmv file to virtualdub, and then dump the entire image sequence to hard drive, and the reload the image seqence and crop it to create 480p file. no difference. i think the problem is probably the wmv plugin i used for virtualdub.
later i found out if i use Sony Vegas to directly decode the wmv video and dump it to 720p image seqneces, then this tool will properly do 420 to 444 upconversion. from there, using virtualdub to crop images (use brightness/contrast to enable "crop" option) becomes OK ...
ha ...
posted by jameszhou2000 @ 12:09 AM
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