Lots of blocks appearing...

[cogd115]

I encoded Terminator, the first one, and found some scenes quite blocky (is that the problem of macroblocks?)... More specifically, the scenes in which the terminator gets engulfed by the flame after the truck explosion, one part of the chase sequence in the factory, and a few scenes at the last segment (Sarah at the gas station). Everything else seems very fine. What would be the cause of this abrupt appearance of macroblocks? I have read that too many pixels may cause this. It was a three cd rip, the pixel*frame was, if I remember correctly, 0.356. Would this have been the cause?

My setting was: motion search of 6, mpeg quantization, vhq of wide search at 4, chroma motion, and everything else at default with nic's xvid.

Thanks in advance for your replies...

[Soulhunter]

Have you done a compression test ??? :rolleyes:

When yes, what does it tell ?

When no, make one !

When you don't know how to do one...

Read the guides, or use the search function ! ;)

Bye

[cogd115]

Thanks for the reply, souldhunter. I did a compression test which showed about 35% over the max (I am not really sure about the precise number but about right on 135%). I thought it would just produce a smaller file (which it did -- 1.8 gig rather than target size of 2 gig) without necessarily hurting encoding quality. So, are you implicitly saying that the cause of the problem may be the pixels, too much of it? I am quite perplexed as to why this occurs as I never had this problem before..

[Soulhunter]

So, are you implicitly saying that the cause of the problem may be the pixels, too much of it?
No !!! :p

When the file is allredy undersized, lowering the pixels (Resolution) would decrase the filesize even more, without getting rid of this blocks...

Usually there should be no "visible" blocks in the pic, when you have reached the maximum filezise/quality !!!

Are you sure, that they are not allready in the source ?

When yes, try trbarry's DCT filter...

When not...

What kind of "blocks" you see there exactly ?

Means...

Are this blocks big (8x8 pix.) or are they small (2x2 pix.) ???

When this blocks are of the big kind...

You can use AviSyth filters like "BlockBuster" to prevent them...

When they are of the small kind, and mostly visible in high intense color arears, especially in red ones...

They could be caused by the "chroma upsampling bug" !


Here (http://forum.doom9.org/showthread.php?s=&threadid=38304&perpage=20&pagenumber=1) is a link about a thread how to solve this chroma upsamling bug !

The DCT & BlockBuster filter can be found here (http://forum.doom9.org/showthread.php?s=&threadid=51320&highlight=blockbuster) !


Bye

[cogd115]

Well.. I am not sure what you meant by "big or small" regarding the size of the blocks. My laptop screen is 15", and the movie is 16x9. Watching it in full screen given the matted format, the size of the block appears to be of 0.4cmx0.4cm (or one sixth inch by one sixth). I see a whole drape of them interweaved horizontally and vertically in the flame scene wherein the terminator gets burnt alive. One interesting thing is that the blocks do not appear in the scenes in which only flames are shown without the terminator is in it. In one short part of the chase scene in the factory, again the army of the blocks covers the terminator in metal. At the end segment, the blocks appear, though far less prominently comparing to the scenes I described above, around the face of Sarah's. All about same size.

The DVD source is clean. No visible noise in those scenes. I will try some of the things you mentioned. Thanks for the links.

Total time affected by the blocks is about 80 seconds, I figure.

[Soulhunter]

Just for completeness...

You can also try if disabling "chroma motion" changes something !?!

PS: Have you used it together with "chroma optimizer" ???

Bye

[cogd115]

Actually, I was thinking about encoding the Terminator without chroma motion as you mentioned chroma bug -- just for experiment. And, yes I did use chroma optimizer with frame drop ratio of 0 -- would it change anything if I change the value of the parameter?

At any rate, thanks for your thoughts and help. :)

[Soulhunter]

This "chroma bug" has nothing to do with XviD's "chroma motion", its only a colorspace problem, and what you wrote you have only the usually marcoblocks... But for the fact, that I haven't done much testing with "chroma motion" I don't know if there maybe some side-effects that it could produce !!!

Uhm, yeah !!!

Before I forget to ask that too.. ;)

Could it be that theres something messed up with XviD's credits option ???

This recently happens some other PPL too...

Check if you have disabled it !

Bye

[BoNz1]

I encoded this movie recently, my advice is to definitely not use mpeg quantization. Use h.263. I don't think there is any bug in the chroma motion, but there may be one in the chroma optimizer, I remember reading something about this when it was fixed in dev-api-4. And don't use any heavy filters it will only look worse, IMO. Anyhow, I would also recommend that you use b-frames 1,150,75 since it seems that in the dark scenes (and there are a lot in this movie) way too many b-frames are inserted at way too high quants which looks bad. Also, don't use any qpel. BTW, I think you should be able to get this movie onto 2 cds w/ a 5.1 AC3 track, I did, ;)

[CruNcher]

@BoNz1

please don't missinform people like that in saying this and that is bad qpel is a matter of taste it preserves more details it's not bad and if you wan't optimal b-frames you could also use 1/150/0

[cogd115]

BoNz1, thanks for your suggestion. I used it with a great result. First of all, the macroblock problem is 99% toned down. I can only see the blocks for a few seconds in the terminator-gets-flamed scenes -- more specifically, the close up shots. They are gone everywhere else.

Another benefit appears to be less swirling (or moving) background. Though the problem was not prominent with mpeg quatization, I see some improvement when comparing a few scenes with hazy background. Is this supposed to be? I am going to re-encode Sleepy Hollow (which suffers terribly the swirling and moving background even without qpel on) and see what may happen.

Though clarity and sharpness are a bit less, I can live with it. Oh, it was another 3 cd rip with video portion of 1.7 gig. I am not sure if a three cd rip is noticeably better than a two cd one. But just to be safe. :) Thanks once again..

[BoNz1]

CruNcher, I'm not saying it is bad qpel, I just said not to use it thats all. And there are certain scenes in this movie actually the whole movie where qpel looks really really bad and doesn't preserve any more details really IMO. But this one is sort of a red herring it was a very very poor transfer onto DVD and so nothing really does look very good no matter what you do with it. In general though qpel does work well especially in dev-api-4. I was not trying to bash qpel at all.

[trodas]

If you then can stick with the cinema version of T2 movie (witch, IMHO suxx like hell - or at least as soon, as you saw the extended uncut one) - use the WM9 version from Extreme Artiscan Edition DVD and you get very very nice imput quality.
A BIG one too ;) :D

I prefer having my Ultimate and Extreme T2 editions anyway.

I only hope that one day one wise guy invent a way, how to join all the wm9 files into ONE and play them W/O jerking between themselves - not to mention remove the damned wm9 protection :mad: :mad: :mad: