Opinions on resizing from 720x480 to 352x480

[fmctm1sw]

I've been doing some testing with various resizing methods. Id like to try a few "half sizing" methods like high quality 2:1 filter in virtualdub. Problem is half of 720 isn't 352. I've noticed my captures at 720x480 are better than 704x480. I do not see a "crop" function in virtualdub. I'd like to crop off 8 pixels on each side. OR, do I half size FIRST and then crop 4 off each side?

[bugster]

In Virtualdub, once you have added a filter, a crop function becomes available on the main filter setting window I believe. Button appears towrds bottom right of this window.

If the cropping occurs before or after filtering, I don't know, I would hope before.

[fmctm1sw]

Yeah, a classic case of me not thinking again. I can't use those 2:1 reduction filters anyway. The also halve the 480...

I did find the crop function defined on a virtualdub page. I think it does crop before filtering...

[bugster]

Yeah, a classic case of me not thinking again. I can't use those 2:1 reduction filters anyway. The also halve the 480...

True, but the regular resize filter should work best if the resize is a nice half of original size in any one dimension. So cropping 720 to 704 before resize to 352 seems like a good idea to me.

[ronnylov]

If you want to crop without adding a filter (that actually do something) you can use the "null transform" filter and set the cropping. The null transform filter is a filter that does nothing. By adding null transform with cropping first and then the resize filter you will be sure that it crops first.

[bugster]

If you want to crop without adding a filter (that actually do something) you can use the "null transform" filter and set the cropping. The null transform filter is a filter that does nothing. By adding null transform with cropping first and then the resize filter you will be sure that it crops first.

I always wondered why this filter existed