AVI uncompressed to AVI uncompressed - quality loss?

[808-buma]

Hey all
tried to do my first compression on a short AMV in VDMod I'm doing for a friends birthday. I had a simple AVISynth script:

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avisource("myoriginalavi.avi")
ConvertToYV12(interlaced=true)
deen("a3d",4)
mftoon()
crop(8,0,-8,-0)
LanczosResize(384,288)

and because of the deen and mftoon commands, it slowed to a crawl. So, my question is if I split the script betwen the two commands into:

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avisource("myavifile.avi")
ConvertToYV12(interlaced=true)
deen("a3d",4)

save it to an uncompressed AVI, then run a second script to this new AVI:

Code: Select all

avisource("mynewavi.avi")
mftoon()
crop(8,0,-8,-0)
LanczosResize(384,288)

and then save this to another uncompressed AVI file, will I be loosing any quality at all? From this second AVI file, I then go to my actual compression process to make it distributable...

I know you aren't suppose to recompress a compressed file, but is the uncompressed AVI file okay to do this two-step process?

not worried about having the 2 large files, nor the time involved, but is it just possible to split a script like shown above without loosing quality in the final product?

thanks in advance

[Zarxrax]

You will not lose any quality... but it also makes absolutely no sense, as splitting it in 2 will make it take LONGER.

I also recommend you move the crop and resize above the other commands.

[808-buma]

hehe, thanks for the advice of moving my crop and resize earlier.

Yes, I should have also mentioned that the reason I'm separating it into 2 different runs is basically to see what happens. As this is the first encode that I'm doing, I had no idea what the deen command nor the fmtoon command would do and I did want to compare.

thanks for the response! whew, was sorta worried about quality loss as the originals weren't that good to begin with...

[downwithpants]

you can use beforeafter() to see what each of the filters are doing.

[AbsoluteDestiny]

I also recommend you move the crop and resize above the other commands.

Really?

I find it much easier to successfully filter a large video and then scale it down than to filter a scaled down video.

[FurryCurry]

Well, I'd agree that filtering first would probably give a bit of improvement in quality, but if the OP is concerned with speed, perhaps resizing first would make the filtering go faster, since there would be less pixels per frame to deal with?

Another speed tip:

I'd do all my filtering in one script, then save that finished, filtered video as lossless or uncompressed, then do my encoding from that. If you were to do multiple pass encoding, like a two pass xvid, that would save you the added slowness of running through a slow, filter heavy script twice to get the second pass done. Also useful if you're making multiple encodes of a video for different purposes, like an xvid for downloading, and an mpeg2 for a con submission.

[808-buma]

that's was one of my ideas for splitting the script there FurryCurry - you said it better than I did. Thanks for adding a bit of clarity to a noob's post.

[Zarxrax]

I also recommend you move the crop and resize above the other commands.

Really?

I find it much easier to successfully filter a large video and then scale it down than to filter a scaled down video.

For a size like this you are probably right. I didn't pay much attention to his size dimensions, and I typically deal with resizes like 720x480 > 640x480 myself, in which the difference is negligable. When reducing the video by this much though, you most likely would want to filter it BEFORE you resize.

I WOULD still put the crop before the filtering commands though. I don't know if my fears are substantiated, but I've always been afraid that filters would smear those black, uncropped pixels out into my video :p