cropping, no scaling: bad when rectangle's sides not multiple of 16?

[micmac]

Hello all!

I plan on making a xvid video without rescaling. I want to crop away the black bars around the source video and encode it (with xvid-1.0.3). xvid will store the proper aspect and then my player (vlc or mplayer; I'm on Linux btw.) will read the aspect and make my videocard scale in hardware.
The crop rectangle's sides are not multiples of 16 pixels. Is this ok in case you don't scale your movie before encoding? Or should the "multiple-of-16" rule always be applied anyway (for instance by means of overcropping).

Thanks for your help!

micmac

[Sharktooth]

In any case it's always better keeping mod 16 resolutions.

[Meeple]

This is something I've been wondering about as well.

I've been making some of my encodes anamorphic by cropping off the black bars to mod 8 width/height, then commenting out the resize line generated in GKnot, and finally setting up the correct PAR in the Xvid codec settings.

Should I be concerned that I haven't been doing mod 16 as mentioned above? What is the exact reason there is a drawback to not having mod 16 resolutions? I've been having trouble understanding this, and I thought that mod 8 was safe enough, but now am worried again.

TIA!

[yaz]

mod16 is sg coming from the encoding process. most encoders work w/16x16 blocks so keeping mod16 resolution makes their life easy. however, the limitation of xvid is mod4/mod2 (iirc).
on the other hand some players have problems w/playing back non-mod16 resolutions. some others even require mod32 horizontal

all in all, it's rather a question of portability then that of encoding

the bests
y