Best resize algorithm

[cd090580]

Hi,

I want to resize a vcd resolution to a dvd resolution (I know I wont expect a very great quality).

But I dont know which resize algorithm is the best:

Bilinear,
Bicubic,
Lanczos
....

The VCD is from a Digital TV source, so there are no noise (except a few macroblocks in scenes where there is more action).

What resize algorithm is the best ???

Thanks.

[guns1inger]

I would use virtualdub, and first apply the MSU deblock filter, then resize using Lanczos. The deblock filter can be hit and miss at times, but it seems to work very well with VCD source.

[dvd3500]

The VCD resolutions are also offical DVD resolutions, 352X288 or 320X240 depending on where you are.
Do some comparisons and see if the DVD player resizing doesn't look better/sharper than converting.
I decided to just leave my VCDs' video as is and only reencode the sound (44.1 Khz to 48 Khz) and authored them as such since reencoding:
Took time
Made the picture too soft
Made the file unnaturally larger

[mats.hogberg]

Since resizing requires reencoding, I'd strongly advise against it, if your aim is to author a VCD mpeg as DVD. There's only quality loss up that road.

/Mats

[cd090580]

I know it's better, but I'd like to put all my videos in only 1 VTS so they must have the same resolution.

[dvd3500]

Compatible Video CDs ONLY have have ONE resoltion as stated above so I don't understand why this is an issue. Why is 1 TS important?!

[mats.hogberg]

Maybe it's not just VCD material?

/Mats

[dphirschler]

I like bilinear resizing, but to resize VCD (352x240) you should just use pixel resize. No reason no to since it will be just doubling the size (704x480). You may want to add a border of 8 on the left and right (after resizing to 704) to get it to 720x480.


Darryl

[dvd3500]

Maybe it's not just VCD material?

Possibly... but with playlists and other features other freeware DVD authoring offers you can get around that too without reencoding.

[spectroelectro]

Guns1inger nailed it. Just doing pixel resize still leaves you with the crappy looking 1150 kbit bandlimited aliasing blocks you get from VCD encoding, except 4 times as large, which looks really *really* bad. Lanczos is a modified bicubic and will produce the smoothering scale-up interpolation. But you must run MSU deblock, and you might want to try some other smoothing filters in addition inside the filter chain when you run VirtualDubMod.

A whole lotta folks are taking mpeg-1 TV show downloads and just turning 'em into DVDs with straight mpeg-1 to mpeg-2 conversion via pixel resizing, and it looks craptacular beyond description. Unwatchable.