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View Full Version : differences in crop between avs 2 and 2.5


Lobuz
14th January 2003, 22:30
I wanted to compare speed of avisyntch 2 and 2.5. For 2 I used vdub and for 2.5 vdubmod and I put mpeg2dec3.dll, avisyntch.dll in its directory. I used the same crop and resize parameters:
crop(2,1,718,574)
LanczosResize(640,352,0,0.75)
Results were a little different. In 2.5 the picture was a little shifted vertically by pixel or two with black line witch was suppose to be cropped.
Finaly identical results were with
crop(2,2,718,572)

Is this the specific of YV12 that sizes must be multiplayer of 2 or 4 ?

hakko504
14th January 2003, 22:33
Yes! Check this thread. (link) (http://forum.doom9.org/showthread.php?s=&threadid=40413&highlight=YV12)


@Wilbert

I've added the information in this thread to the crop page at www.avisynth.org but maybe this should be mentioned in the FAQ instead. It does concern resize as well. In any case I'll add a crosslink from the FAQ setion about colorspaces to the crop page. Done

Lobuz
14th January 2003, 22:53
Thanks :D

Wilbert
15th January 2003, 10:59
@hakko504,

If www.avisynth.org is accessible again, I will look at it.

sh0dan
15th January 2003, 14:08
@hakko: Good work - I was about to make a similar description in the development section (link name ColorSpace or ColorSpaces), but for the good basic explanation, I'll just link to yours :)

Seems like sourceforge is having a hickup again - let's hope it gets fixed soon.

hakko504
15th January 2003, 14:26
Thank you. When I saw Lobuz post last night I realised it might be a good idea to add this information to www.avisynth.org because there are some people who have asked about crop modulos before, and probably will again. It does however mostly concern the basis for an advanced user and not a developers point of view and I'm sure you can add a lot of stuff on that aspect. I think that in order to really understand why different modulos should be used in RGB/YUY2/YV12 you need a little technical background and I hope I have provided it in a language that can be understood by someone that have some experience in computers.