Simple Pixel Doubling?

[Corpsecreate]

I have a 640 x 480 clip and I would like to directly duplicate the resolution to 1280 x 960 by duplicating each pixel. I imagine this would cause no artifacts and would be a very fast resize. Is there a resizer that can accomplish this? Also is there a way to halve the resolution by removing every 2nd pixel (ie go backwards from the upscale)?

Any help is appreciated ;D

[sneaker_ger]

PointResize() ?

[TheFluff]

Doubling the resolution in both directions is pixel quadrupling, but yes, pointresize() will do that. For the other direction you can use either pointresize() again or reduceby2().

[Corpsecreate]

Thank you very much for the help. I did a quick test by subtracting the pointresized image from the original and I get a complete grey image as expected. When I used reduceby2() to go backwards I got a slightly blurrier picture with edges showing up on the subtracted image. Thanks for the help guys!!

Edit: Another quick question if I may. When it comes to Spline36 vs Lanczos4, which is faster to process? I wont ask which one looks 'best' because thats subjective but one should be faster than the other.

[Gavino]

When I used reduceby2() to go backwards I got a slightly blurrier picture with edges showing up on the subtracted image.
Yes, ReduceBy2() does anti-aliasing and blurs the image -it's similar to BilinearResize in effect.
Using PointResize will losslessly restore the original image.

When it comes to Spline36 vs Lanczos4, which is faster to process? I wont ask which one looks 'best' because thats subjective but one should be faster than the other.
Spline36 is faster as it processes fewer pixels (equivalent to Lanczos(taps=3)).
Lanczos4 is the same speed as Spline64.