virtualdubmod cropping

[fishywishy]

im trying to crop a 1920x1080 vid down to 960x540 by taking off 480 on each side and 270 on the top and bottom. but when i get to the cropping toolset the 1920x1080 window is too big that i cant get the "y" textbox to show since its at the bottom of the window. i have a 22" widescreen monitor at 1680x1050. is there a way i can scale down the preview window? or a manual prompt? thx

[neomaine]

Use the nulltransform filter. It'll crop to your hearts desire...

[manono]

I think resizing to 960x540 is a much better idea than cropping, as you won't lose any active video. Both have the same ratio. If there are black bars, then crop more from the top and bottom to make 960x400 or whatever. Doing it your way you'll lose 3/4 of the movie (assuming no black bars originally).

And if you do any cropping and resizing in an AviSynth script, not only will you not have the problem you're having, but the encoding will result in better quality in much less time.

[jagabo]

If you still want to use the crop function in VirtualDub here's a workaround for the too-big-window problem: After starting Virtualdub, but before opening your video, add the Null Transform filter. Add Cropping to that. Set the cropping values as you want (you'll have to type in the values). Now open the 1920x1080 video file.

[fishywishy]

Doing it your way you'll lose 3/4 of the movie (assuming no black bars originally)

actually ill lose 1/2 the video, and thats the idea

thx for the Null Transform tip, ill try that when i get home

oh and i look forward to trying out avisynth tonite

[jagabo]

AviSynth: Crop(480,270,-480,-270)

[fishywishy]

well the null transform works great. turns out i already have avisynth installed. i dont know how to use it though since theres no exe file to run

[AlanHK]

well the null transform works great. turns out i already have avisynth installed. i dont know how to use it though since theres no exe file to run

You write an AVS file (plain text).

eg

AviSource("filename.avi")   #open the video file
Crop(480,270,-480,-270)

save as "filename.avs", where"filename" is whatever your video file is.

Then open that with VDub. The commands in the file (usually various filters) will be executed and the result displayed.

Avisynth added items to your Start menu. That includes a "Documentation", a comprehensive collection of HTML help files.

[manono]

actually ill lose 1/2 the video, and thats the idea

No, actually you lose 3/4 of your video.

1920x1080=2073600 pixels
960x540=518400 pixels
518400/2073600=0.25

When finished doing it your idiotic way you wind up with 0.25=25% of what you started with. It's much worse even than a pan-and-scan version of what was originally a widescreen video.

[jagabo]

When finished doing it your idiotic way you wind up with 0.25=25% of what you started with. It's much worse even than a pan-and-scan version of what was originally a widescreen video.

Not if what he's interested in is only in the center 25 percent of the frame.

[manono]

But he thought he was getting the center 50% of the frame. He was wrong. I'm not convinced that's what he was after, though. Resizing rather than cropping (or combining the 2 if he really wants to butcher the video by cutting off some of the sides and/or the top/bottom) is an immeasurably better way to do it. I'm suprised you're supporting him.

[jagabo]

I'm neither supporting him nor trying to dissuade him. I'm letting him make his own decision. There's no reason to assume he's talking about doing this to a whole movie. It might be some home video with nothing of interest at the sides. Or maybe he wants to highligh something in the middle of the frame without losing any resolution -- small text for example. Why do you insist on calling him idiotic when you have no idea why he's doing what he's doing?

And whether he's losing 50 percent or 75 percent is a matter of whether you're talking pixels or linear resolution.

[fishywishy]

No, actually you lose 3/4 of your video.

When finished doing it your idiotic way you wind up with 0.25=25% of what you started with. It's much worse even than a pan-and-scan version of what was originally a widescreen video.

yeah i guess ill lose 3/4 the video. i was thinking of 1920 /2 and 1080 /2 gives me 1/2 the height and 1/2 the width

calm down. if i crop the sides, the action that im zoomed in on will stay the same size. if i resize the whole video everything will get smaller. thats the idea, and it worked great when i used the null transform thank you very much