VirtualDub - Which resize method is better?

[ThePrimal68]

Hi,
I'm using VirtualDub and although I did encode plenty of clips with it I was wondering which of the many options to resize your source is the best. There are Precise Bilinear, Precise Bicubic 0.75, Precise Bicubic 1.00, Precise Bicubic 0.60 and Lanczos3.
Any thoughts on that?
Thanks, theprimal68

[UncasMS]

lanczos is my one and only choice

sharp and still good compression

[ThePrimal68]

thx

thanks, so I will stick to Lanczos3 from now on

[UncasMS]

maybe you should make a couple of tests to see for yourself

take a small vob file and have it converted with all different resizers and afterwards compare for yourself.

[lord_shar]

Disclaimer: DivX rookie here

I notice that I get horizontal "scaling" lines whenever I resize a VOB 720x480(?) movie down to a 320x240 DivX AVI with VirtualDub (via resize filter). I get no such lines when converting the same source into MPEG1 via TMPG bicubic.

Is there a way better resize the video without getting these band-lines? Should I just rescale with TMPG, then use VirtualDub to produce the final DivX file? Will this create audio/video timing issues?

[setarip]

To lord_shar

What you've described indicates that you're dealing with an interlaced source - for which you'd have to apply a (logically) DE-interlacing filter when converting to DivX...

[lord_shar]

Yes, the source is NTSC 29.97 interlaced.

The horizontal lines are present on every output frame and are spaced evenly about 20-30 pixels apart. I remember applying the deinterlace option in DivX Pro 5.05's 2nd tab, so I am not certain that applying a second de-interlace filter will solve the issue.

I've seen this in occur when shrinking other non-interlaced video, so I don't believe VirtualDub's resize filter matches the scaling quality of TMPG.

The problem with TMPG -- it takes 3+ hours to resize the 720x480 video down to 320x240 at CQVBR, MPEG1, 27.97fps, 3000br max, 100 Quality setting on my PC. (I'd use MPEG2, but that requires the full commercial TMPG version).

[UncasMS]

picking the best virtualdub filter is one thing

i would NOT, however, dare saying tmpegs filter are in any way better or more efficient than vd filters.

there's hardly anything you cant successfully acomplish with vd + filters

[lord_shar]

I'm not sure if you understood me correctly... I was specifically refering to VirtualDub's "resize" filter only (and none of the others) compared to TMPG's default rescale.

Can you recommend any filters and/or settings which might remove these horizontal scale lines? I don't believe it's a problem with VirtualDub specifically, since I've also observed these lines while encoding with XMPEG and Flask. Perhaps it's an issue with the rescale in the DivX 5.05 codec rescale function?

I'll attempt to upload an image later to clarify the situation...

[UncasMS]

i dont rust divx rescale functions, thus i cannot judge if that function might be worth using or not

lanczos with some sort ofvd or avisynth deinterlacing/telecide filters worked fine for me so far.
decomb, telecide, greedyhma - it is a matter of what routine you use/prefer

my tool of choice is DVX which gives you easiest access to these options

[lord_shar]

I finished using TMPG to resize the video file down to 320x240, then converted this into a DivX avi via VirtualDub (without any further filters). While this resulting TMPG mpeg1 file rescaled fine, those horizontal lines reappeared in the DivX avi encoding (despite no additional rescale being done). As a result, I can only "guess" that these lines are a result of encoding with the DivX 5.05 codec and not a consequence of any resize operation.

These lines aren't too noticible... it's just my eye being a little too picky. DivX's image quality, higher supported bit rates, and smaller file sizes make up for the slight inconvenience.

Thank you for your suggestions nonetheless