Dancing?

[j7m7r7]

i'm using GK to rip DVDs, encoding with XviD. on every rip, i'm getting what i can only describe as a dancing, or fluttering effect, almost always showing up in the foreground of the picture (i.e., the walls) and strangely enough, on people's clothing. other than that, picture looks good. the effect seems to show up regardless of resolution (704 X xxx, 640 X xxx, etc.). i'm keeping bits/(pixels*frames) between .25 and .3, making sure i'm getting between 50 and 80 percent when running comp. test. maybe have 1100-1200kbs on average.

is this a common effect that maybe a filter might help with, or maybe just caused by me screwing with my xvid settings a little too much...

[Baldrick]

It is pretty common on xvid, divx. I don't know how to reduce it. I would recommend http://forum.doom9.org/forumdisplay.php?s=&forumid=28

[manono]

Hi-

Hehe, that's my forum, Baldrick. I mod there, and if j7m7r7 were to post the same question there, I'd give him the same answer as you just did, although wasting a lot more words in giving it.

In my opinion, moving blocks on solid colored backgrounds is the most serious problem of MPEG-4 compression. Maybe j7m7r7 is viewing on an LCD monitor. The problem is much more pronounced on an LCD than it is on a CRT monitor or a TV set. There have been a number of attempts to tackle the problem, most of them in the XviD Forum at Doom9, and a search there will turn up many threads on the subject.

Proposed solutions include using a higher bitrate, using a higher bitrate matrix, using a higher resolution, disabling B-Frames, adding grain, either during encoding or during playback, and using various filters. One definite help is to turn off Adaptive Quantization if you're using it (my personal opinion).

[j7m7r7]

thanks very much to both of you for pointing me in the right direction.

as a matter of fact, i am viewing on an LCD. i hadn't thought about that. i'm not using adaptive quantinization, but other than that, it sounds like i've got a lot of areas to explore. will go searching on that other forum and see what i can dig up. thanks again

[manono]

Hi-

I forgot to mention one thing, and that is XviD's default H.263 matrix shows these blocks more easily than does the MPEG matrix. That's a slightly higher bitrate matrix. If you really want to go further, then get and learn how to use some of the high bitrate Custom Quant Matrices, such as the 6of9 matrix, or one of Soulhunter's high bitrate CQMs. You'll see definite improvements, but at the expense of compressibility. That is, if you're backing up to 1 CD, then you won't be able to use them with good results. If you don't mind putting only 2 or, at most, 3 movies on a DVDR, then they can do wonders for your encodes, and they'll rival a full DVDR MPEG-2 DVD backup. All the information is available at the D9 XviD Forum.