Help: Auto GK

[stan101]

I am trying to shrink the size of an AVI file using Auto GK but whenever i select the video and click start , i get the error message "AVIsynth open failure : convert to YU2 : image width must be even , Use crop!" . Please what am i doing wrong and if the error message is because of cropping then how can i crop my video to have the same image width ? . Please help . Thanks

[Selur]

the point is to use cropping in a way such that image width&height are even numbers.
733 -> not even
732 -> even

[stan101]

here is my AVI file analysis from media info:

General

Format : AVI
Format/Info : Audio Video Interleave
File size : 53.5 MiB
Duration : 3mn 42s
Overall bit rate : 2 020 Kbps

Video
ID : 0
Format : TechSmith
Codec ID : tscc
Codec ID/Info : TechSmith Screen Capture
Duration : 3mn 42s
Bit rate : 2 014 Kbps
Width : 313 pixels
Height : 224 pixels
Display aspect ratio : 1.397
Frame rate : 15.000 fps
Bits/(Pixel*Frame) : 1.915
Stream size : 53.3 MiB (100%)

autogk
original 640 width



so how do i crop now ?

[Selur]

Width : 313 pixels
Height : 224 pixels

+

original 640 width

-> ???

Your source has a width of 313 -> you need to crop the width to i.e. 312

[stan101]

how do i crop the width to 312 and why exactly do i have to crop it to 312 . sorry for the noob questions , i just want to know why so that next time i would know what i am doing .

[Selur]

how do i crop the width to 312

you can press Control-F9 to launch "autogk[/B]-assistant.htm]AutoGK assistant" and configure the current job.
You need than to enable 'Force cropping' and crop 1 on the left or right side. (in the cross)

why exactly do i have to crop it to 312

- you could also crop to another even number but 312 is the next even number lower than 313.
- your width&height must be even numbers because the chroma sampling most of the modern compression methods use to not allow uneven numbers. (usually it's 4:2:0, see: http://en.wikipedia.org/wiki/Chroma_subsampling)

Cu Selur

[stan101]

Okay thanks a lot , i'll try that out and get back to you

[stan101]

Hi i held ctrl +f9 and this came out . where do i assign the new size ? i can't see force cropping option also .

[Selur]

they renamed a few thing since I last used autoGK a few years ago,..
->
- enabled '.autocrop->tune auto crop parameters'
- set the cropping in the cross under '.autocrop->Force cropping of:'

[hello_hello]

I could be wrong, but I think you'd need to crop the video as it's decoded, not afterwards using AutoGK's crop function as AutoGK uses AVIsynth to do the cropping, so you'd need to get AVIsynth to open the video in the first place.
For instance if you're using ffdshow to decode the video (AutoGK decodes AVIs via DirectShow) then you'd need to use ffdshow's resize (or crop) function. Probably the easiest way would be to use ffdshow to resize the video to 312x224 which should stop AVIsynth from complaining. From there you can use AutoGK to crop it further if need be, although you probably won't need to.