reds...neons...crappy

[Hectic]

i noticed when encoding with nandub, neon lights and red colors encode badly...it's almost like the movie was encoded using nearest neighbor as the image filter while resizing but i know for a fact that it wasn't...very digitized looking..blocky on the edges of the neon sign or red object...i've looked at movies i've encoded or downloaded and they all have this problem with neon signs and bright red objects...rest of the image in the movie is smooth...anyone know why this is? or how to prevent it from happening while encoding..it's not a huge deal but i'm just wondering if it's a problem with my codec or something...i doubt it scince the rest of the image is clear and smooth. does it have to do with resizing? any why are demensions supposed to be multiples of 16? does it have to do with image quality? and if it does, when you crop the image to remove black bars, shouldn't the amount of pixels removed be a multiple of 16 as well? thanks..late

[Acaila]

You can lessen the effect by using a good bicubic resizer and a higher bitrate, but what you see is mostly a result of colorspace. RGB stores all channels equally, but YUY2 and YV12 (which most divx's are encoded in, and you can't change this) reduce the information of the chroma (=color) channels.
YUY2 only has chroma information in every second pixel horizontally while keeping full depth vertically. YV12 has chroma information on every second pixel horizontally and vertically (thus 1 out of 4 pixels). This helps in reducing the filesize. The fact that the human eye cannot notice color changes as much as luminosity changes makes that most of the time you won't see this. The only time when it becomes (painfully) obvious is with large areas of bright colors, like your neons.

[Hectic]

thank you...i'll let it slide and forget about it considering it isn't much of a problem because of the fact that 99.9% of the images in movies aren't bright colors or neon lights and when i watch divx on my tv from the output on my video card, it's not even noticable due to the lower resolution and alternating fields compared to my computer monitor where i noticed it..i'm just glad it doesn't have to do with the way nandub encodes on my pc..thanks again.......