Can avisynth take screengrabs in .png?

[thegame]

Hi Everyone,
I was wondering if a script can be made to take screen grabs in .png? like if I am comparing 2 video sources and want to take a screen grab every 5 mins in png format to work with the images instead of the video? I hope this can be done, it really stinks taking all these shots 1 by 1 through the entire video lol, would be nice to have some kind of automated process.

Thanks

[Asmodian]

ImageWriter (http://avisynth.org/mediawiki/ImageWriter)

[mandarinka]

I find it more handy to load both sources, interleave them, and look at it in virtualdub.

[thegame]

I find it more handy to load both sources, interleave them, and look at it in virtualdub.

What do you mean interleave them? right now I have them stacked on top of each other for comparing in VDub, but I need screens to for making adjustments, it is a lot easier to take the screens into PS to figure out what to do before making a script.

also thanks to the poster above you for the link, I will try and see how I can fit that in to my real basic video comparing script lol.

Thanks

[Reel.Deel]

What do you mean interleave them?

a = avisource("whatever source")
b = avisource("whatever source")
interleave(a,b)

[mandarinka]

Yep. If you move back-forth between the alterantive images (assuming they are aligned temporally and ideally spatially too), you can spot differences between them much more effectively than in side-by-side view (and don't make me start on viewing angles of LCDs, haha). I would say that it's actually the only way to spot the tiniest differences (to get the most out of it, you can align the two frames by addborders()/scaling to make them completely aligned - it reveals the difference between frames best).

[wonkey_monkey]

[quote]I would say that it's actually the only way to spot the tiniest differences{/quote]

You could also take a difference of the clips, perhaps stacked next to the interleaved frames, which makes it easier to spot differences when playing at high speed. You could also do some selecteverys/stacks/shrinks to make a big grid of frames to so you can look at multiple difference frames at once. That's what I did when I wanted to look for errors in my formula for identifying and undoing interlaced frames in some telecined video.

Edit: umm, that's assuming that's what the OP wants to do in the first place, of course - we might be straying a bit!

David