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Old 18th May 2012, 05:58   #2  |  Link
hello_hello
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Join Date: Mar 2011
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Quote:
Originally Posted by hunter_aran View Post
Well I encoded one of these messed up files again, this time cropping 4 off the bottom and behold the Mediainfo window says the aspect ratios are the same! Why did the non-cropped one have a discrepancy and not the same one cropped? Any ideas...? Is this that ITU thing I don't understand?
Someone else may be able to give you more exact information, but as long as MediaInfo says the original and display aspect ratios are the same I don't think there's anything to worry about.
I've seen the same thing from time to time (MediaInfo showing both original and display aspect ratios which are the same), even though there is only one display aspect ratio.

What I suspect happens is sometimes the aspect ratio written to the video stream and the container aspect ratio are stored differently even though they're the same. ie one may be 4:3 while the other is 640x480 (or something similar) and for some reason MediaInfo sees them as being different so reports both, even though in the end it reports them as being the same.

MediaInfo also "rounds" the aspect ratio quite a bit. It seems to report standard aspect ratios (4:3, 16:9, 2.35:1 etc) and everything in between gets "rounded" to the nearest "standard". For instance I just checked a 704x384 AVI which has an aspect ratio of 1.8333:1 but MediaInfo reports 1.85:1.
So it's probably some combination of the way the two aspect ratios are written and the way MediaInfo rounds them which causes it to sometimes show original and display aspect ratios, while sometimes only showing a display aspect ratio, but as I said I've seen it happen plenty of times before (in fact the third anamorphic MKV on my hard drive I checked with MediaInfo showed two display aspect ratios which are the same) so whatever the reason it happens, I'm sure it's nothing to worry about (unless of course MediaInfo reports the original and display aspect ratios as being different).

PS It wouldn't have anything to do with ITU vs non ITU resizing. That's a choice on how to resize a DVD for playback. The "official" ITU resize methods aren't exactly 4:3 or 16:9, however in my humble opinion most DVDs don't use ITU resizing. The encoded video will have a specific aspect ratio after cropping regardless of the resize method used when encoding, only the aspect ratio will be slightly different depending on which resize method you use, but either way it's not the reason for MediaInfo sometimes reporting the aspect ratio twice.

Last edited by hello_hello; 18th May 2012 at 06:12.
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