anime block removal

[exo-tech]

hi, i was wondering if there was any common way to remove blockiness during gradiants or patches of similar colors [walls] -- attached is a screenshot at 1:1 of an anime i'm currently ripping, and everything is fine aside from the blockiness which tends to really be annoying =(

i've tried both xvid and divx 5.03, and they both exhibit this problem. the divx br was 1167 and divx br was 1344. 640x480 -- is it a filter/plugin i need or does every encoder encounter this from time to time?

http://members.aol.com/beniexo/rw.jpg

[Zarxrax]

That's caused by compressing too much. Increase the bitrate, or lower the resolution. If the blocks are in your source, use a spatial smoother to filter them out.

[esby]

Maybe i'm totally wrong,
but it seems a particular case of DCT blocking?
Could adding noise during encode could reduce this effect in theory?
(using blockbuster filter).

esby
PS: this is more a wondering than a real suggestion :)
Personnaly i wont add noise to an encode ^^

[digitize]

Yeah, like esby said, perhaps adding noise (detail) to it would remove the dctblocks, not too many other ways to do it.

[angelyote]

If you don't mind a larger file size try turning off b-frames.

Recently I had some problems in an anime where I was seeing a lot of blocks in an area that faded in from black and then out to black. I was already maxing my file size and tried a lot of different filters and tricks. Finally I just tried disabling b-frames and it worked.

*This part is pure speculation. I do not know exactly how the encoder determines which parts of which frames are ok to reference backwards or forwards*
Maybe during fade-ins and fade-outs you're getting b-frames referencing previous or future frames that don't seem different to the encoder but do seem different to us. So you're getting the brighter or darker blocks of the surrounding I-frames. Maybe there's a way to tweak b-frames (via a threshold) to tell the encoder just how similar blocks need to be in order to be able to copy them...

Anyway, disabling b-frames worked for me and since I was already getting an acceptable filesize with high bitrate I decided I didn't need to worry about it. YMMV.

Dave

[exo-tech]

tks for your replies -- been very helpful. =) however, i'm not an expert encoder, hell -- im not even sure what b-frames really are...hence newbie questions =) but it's all good, my experience is just sprouting...thanks again =)

[sh0dan]

It has been discussed in the XviD forum. Search there!

Turning off B-frames will help.
Try Sangrips Blockbuster.
Try the Luma filter solution described in the XviD forum.