Some weird color problems with some encodes.

[NeVeRLiFt]

Me and a friend have both had this happen and I have even downloaded a movie that a certain group released that was called the Badge and stars Billy Bob Thornton in it. My friend mentioned a while back he would post on this weird problem... not sure he ever did.
I was not gonna say nothing as I figured it was something I was doing wrong with the settings for the encode. But after seeing the same problem with this movie made by this group I thought it best to make a post.

The problem is hard to describe at least for me. But the two problems I have noticed are this.

1) During certain parts of the movie/scenes that have certain kinds of lighting in them you will get a ghosting/bleeding/smearing effect of the lights on objects/people in the scenes. Sorta spooky looking and weird.

2) The weird color problem(green, blue, red and purple) this problem is nothing like the first one I mentioned. What happens is these colors appear and run through the scene and last until the next Key or I-frame I think. Its not all the colors at once, its just one of them.
The last time I saw this was with a encode Stabmaster-Arson made and it was very crazy looking and it was purple.

If need be I can upload a small sample to someone or some place.

Has anyone else had this problem or know whats causing this.

[Koepi]

Well, I've 2 news for that:

a) I could produce those results once, too.
b) I terribly messed up my system to make that happen.

I don't remember exactly _what_ I did, but i did torture everything I could:
- I randomly changed bytes in the video bitstream
- I used unstable settings in the encoder (i.e. GMC)
- I _did not_ use ffdshow
- I played around with hardware acceleration level in WMP as well as with the overlay settings
- and last, the worst: I used weird compiler settings for my xvid dll.

So theere might be a soluteion:
- use ffdshow for playback
- use the stable build.
- some others I can't think of now as I'm too tired already (hell, 4am again, I should really try to sleep at nights).

Best regards
Koepi

[NuclearFusi0n]

what are you using to decode? does the problem occur when you load the movie in vdub?

[NeVeRLiFt]

Its not a decoder problem, its in the encode.

[ChronoReverse]

So you've actually checked the file using vdub?

It could simply be a case of a corrupted file. That can easily cause such a problem. Did you try FFDshow?

In any case, this shouldn't happen if an encode was done properly (of a dev build might have a bug in it since it _is_ "ustable")...

[NuclearFusi0n]

if this is happening with both your encodes and a downloaded encodes, i would bet money that the problem is with your decoder.

[Acaila]

I've seen your first problem also, back when XviD's QPel was first being introduced. My guess is that the video you downloaded was encoded with an earlier/unstable form of the QPel code. Since then a lot has changed in both the encoder and decoder, so like Koepi says just to be on the safe side install ffsdhow for decoding as it generally plays the older XviD versions better than Nic's decoder.
Do you still have these problems with the newest XviD builds, or are they from a while ago?

[((( atom )))]

very funny NeVeRLiFt brought that up. there is this huge thread about koepis new releases and so i thought i don't join in, but now i saw this thread..

i have been fighting hard for a week now to manage to get around those smearing-effects when using qpel. i tried practiacally /every/ setting + combinations there could possibly be, i tried all the latest few builds of xvid + decoder + ffdshow, i won't help - smearing whenever i use qpel and yesterday i actually gave up..

what really confuses me, is that is is definitely not in the encodes - simply gone, when i use virtualdub. nics filter doesn't help it and also ffdshshow with whatever settings can't help it.

i guess that is is connected with the directshow-engine, since i remember that avery lee wrote his own (and great - jumps to keyframes like a charm..) rendering-engine.

i'd love to tell my windows to use virtualdubs engine for video-playback, but that will be not possible, i am afraid...

[Koepi]

Try the latest ffdshow alpha - it seems to produce less-smeared output. (ffdshow-20021213.exe i think it is).

Regards
Koepi

[((( atom )))]

i use that one. same results.

well, after all, it is not to bad. xvid gives fine results, anyway and i know qpel is on its way...

[NeVeRLiFt]

Thanks everyone.
So the ghosting/smearing effect with the lights is a Qpel problem or maybe decoder problem.(I only noticed this effect when certain lighting was in the scene... say lights from a cop car or off a store sign, and them floruescent lights used in schools and office buildings)

Now what about this color problem? Its crazy and hard to describe...
just say your watching a movie and all of sudden the color purple(for this example) just appears in the scene and runs through the scene till the next Key or I-frame I think. Then is gone.

[sysKin]

Smearing artifact is a known qpel bug. I tried to fix it many times, and I'll try again.
It appears that xvid doesn't do halfpel interpolation in qpel mode correctly. I tried a way which looked correctly to me, but it was still wrong.
This is weird, this is known, this will be fixed eventually...

As for color - you're using ffdshow to play the clip, aren't you? Well this is great, just set options->miscellaneous->IDCT to "xvid".
This should also help witth similar problems in divx4 and 5.

Radek

[Stabmaster-Arson]

I had teh same issue about 1 month ago with nics (at the time) latest build.

It would happen about eveyr 5-10 minutes (I encoded it myself, the move was bad company)


It was in the encode. I grabbed the shopts from vdub. IF anyone wants to see them respond so and I will put them up and link them.

[NeVeRLiFt]

Post some samples so they can see it. (the weird color problem thats in the encode)

I believe Qpel causes the ghosting effect I mentioned...

[Blight]

I've seen that smearing as well. And also the thing where the scene goes gradually greener until a key frame (and this is in the encode, at least it shows like that in vdub as well).

[NeVeRLiFt]

Originally posted by Blight
I've seen that smearing as well. And also the thing where the scene goes gradually greener until a key frame (and this is in the encode, at least it shows like that in vdub as well).

That smearing/ghosting effect is spooky looking in the right movie.
During the Badge they where all in a doctors office(has them lights I mentioned) and looking at a dead body... and the effect was so good and real looking I thought it was a special effect of the movie at first LOL
Before this I had not seen it this bad.

And the worst I have saw the color problem was Stabs encode! You have to see it to believe how bad it is and how crazy it looks.
Its just like a crazy purple wave goes through the scene.

[atcronin]

if only all those useless GROUPS, would just make one quick visit to doom9 and realise not to use qpel and gmc.

just goes to show you how pathetic their rips.

first release i beleive to be using buggy features was Ballistic Ecks Vs Sever, but now most have it. oh well.

[AlphaDivxMovies]

It`s just one of those things, when one get`s used to some method it`s hard to leave.Most Portuguese rippers deinterlace their PAL DVD sources even when everyone knows that 98% of them do not need it.
Go figure!