Artifacts with Q-Pel

[Acaila]

Hi,

I've been testing the Q-Pel builds lately and have now come upon a few artifacts (the only artifacts I've seen so far in the entire movie though). The picture you see below is part of a rainy sequence fading into light. It's only the white part of the frames that show these artefacts. It shows lots of, something I can only describe as, "trailing" (at the bottom near the building, now hardly visible) and darker/lighter blocks (in the sky). The same video encoded without Q-Pel didn't have any of this. For encoding and decoding I used Nic's 10-10 build.

Settings used for this movie are as follows:
Matrix H263/H263
Lumi Masking
Keyframes max:250 min:5
B-Frames disabled
CC: 0% boost, 10 distance, 25% reduction, 20% high, 20% low, delay 500, bias
I/P range: 2-10
Target size 740MB (final average quant 2.54)

Any suggestions or is this a bug?

Ps. Decoding is definately drawing more CPU for me. About 10-15% without, compared to around 30% with Q-Pel. The intro of this movie (X-Men, it's the most cpu intensive scene I've ever seen in my life) draws between 50% and 60% cpu load!
Not blaming anyone, just an observation.

[Koepi]

Hi Acaila,

are you absolutely sure that there isn't ffdshow involved in decoding xvid (neither "decode xvid" nor "using xvid" checked)?
Did you use bframes (everything != -1 is activating bframes code)?
Try without lumi masking again, I think with dev-api-3 I got weird artefacts using lumi masking.

Regards,
Koepi

[Acaila]

- I don't use ffdshow (don't even have it installed), just XviD for decoding its own content.
- B-frames were set on -1, 100% sure of that.

I'll try the same scene without Lumi.

Some additions to my earlier post:
- The left yellow line is not part of the artifacts I was talking about, I think something went wrong there with cutting/resizing/compressing/saving for display on this forum.
- The build I used was today's, which is 11-10-02, not 10-10-02 :)

[Acaila]

Can't get it to reproduce by encoding just that scene (2-pass nor 1-pass modes). Maybe this was just a one-time failure, but I'll re-encode the entire movie just to be sure. It's just gonna take a little longer.

[Acaila]

Ok I encoded the same movie again (both passes) with the exact same settings as before, but the artefacts I saw earlier are no longer there.

[iago]

@Acaila,

In your last encode did you use lumi-masking again?

iago

[Acaila]

"exact same settings as before"

so yes :)

[MaTTeR]

_Update_ Uhg...trashed almost all my encoded movies from today thinking they were bad. Well I just tried playing one of the movies with BSPlayer and noticed the severe "noise" problem disappears and looks great. However, playing the same movie with Zoom Player 2.8 and Core Media Player result in the very nasty noise problem. This problem must have something to do with DirectShow since BSPlayer deals with that in a different way compared to the other players. Anyone have ideas or suggestions? I've never seen anything this odd happen in the last 2 years of encoding. lol


The 10-11 build is giving me very odd results today. Encoded 2 different movies(Enough & Perfect Murder) 7 times with my standard 2 pass encode settings that I used with the 10-10 build. I've used H.263, Modulated and MPEG quants with Qpel. All of the sudden this build is giving massive amounts of mosquito noise, no matter what settings I use. Average quants were around 2.2-2.4, average bitrate 1027kbps and 640 resolution was used (resized with Lanczos, Bicubic and SimpleResize). Anyone else seen this? This definitely wasn't happening with the previous build(10-10-2002)from yesterday. Before anyone asks, B-Frames was disabled with -1 and I'm using Nic's filter with no post-processing enabled.

Unfortunately I deleted the 10-10 build from my PC already:rolleyes:

Acaila, would you mind catching me on ICQ this weekend and send it if you have it? Many thx!

PS. I could post pictures and detailed settings if need be, surely other ppl have seen this though??

EDIT- Uhg...trashed almost all my encoded movies from today thinking they were bad. Well I just tried playing one of the movies with BSPlayer and noticed the severe "noise" problem disappears and looks great. However, playing the same movie with Zoom Player 2.8 and Core Media Player result in the very nasty noise problem. This problem must have something to do with DirectShow since BSPlayer deals with that in a different way compared to the other players. Anyone have ideas or suggestions? I've never seen anything this odd happen in the last 2 years of encoding. lol

Dual AMD XP 1600s
Win2k (Service Pack 3)
Koepi's DX8.1 YUV fix patch applied

[Koepi]

Use WMP6.4 :P
No problems in that direction with it.

MPC could help it as well.

Ah, and please, can you "rewrite" that post so that the playback-program bug isn't announced as xvid-bug? Thanks ;)

Regards,
Koepi

[MaTTeR]

Originally posted by Koepi
Use WMP6.4 :P
No problems in that direction with it.

Well I might consider WiMP an option if didn't suck so bad using AC3 audio. Not flexible enough for my use.

I was hoping to hear from someone else's experience before I post the problem as a bug to Blight or BlackSun.

Edit- Just tested WiMP with my movies and it shows the same terrible artifacts and yet again BSPlayer does not. The artifacts looks like I have the ffdshow noise feature turned on at extreme levels:D

[Nic]

Hi Matter,

Maybe it could be a problem with my DShow filter? (although BSPlayer displays exactly the same for me as WMP). Is there any way you could cut a bit of it out & send it to me?

Cheers,
-Nic

[sysKin]

Hi
Just wanted to tell you that all your xvid/qpel encodings are wrong. Yes, really.
There was (is) a bug which makes chroma compensation completely wrong. now, be warned: I'm not 100% sure that it's really a bug (maybe divx5/ffdshow have the bug but other way?) but I found this problem, fixed it and now all decoders decode the files correctly :)

There is also filesize gain after applying the fix, so I suspect that xvid was wrong :/

I also found some other qpel mistakes, so expect much better quality soon :)

However, I'm not commiting the fix to the CVS until I'm 100% sure that the fixes are correct. So if you want 'fixed' xvid.dll now (or sources), contact me by IRC, details in my signature.

Best regards,
Radek

[Nic]

Im sure we can wait a little while :) Thanks for all your work Radek!

Take Care,
-Nic

[MaTTeR]

Originally posted by Nic
Hi Matter,

Maybe it could be a problem with my DShow filter? (although BSPlayer displays exactly the same for me as WMP). Is there any way you could cut a bit of it out & send it to me?

Well it could be Nic but I'm not so sure. I'll cut a few shots out for you and email them. Thx for taking a look :-)

@Radek
Yes indeed...thx so much for your contribution as well.

[Koepi]

New build up at my site, incorporating sysKins bugfixes committed a few minutes ago.
Shouldn't show artefacts with any decoder now :)

Best regards,
Koepi

[Acaila]

Thanks to both of you, Koepi and sysKin :).
I'll check it out right away.

[sysKin]

Originally posted by Koepi
New build up at my site, incorporating sysKins bugfixes committed a few minutes ago.
Shouldn't show artefacts with any decoder now :)

Nonononono
I'm sorry but it's not the fix :(
It's the 'other mistakes' I had found.

I consulted smart developers and documentation, and it turns out that ffdshow/libavcodec is wrong - not xvid! So the rips you've already made are good.

As for divx5, it makes this one thing correct (ie unlike ffdshow) but has some other strange bugs, which seem to be inter4v-mode related.

So, I'm sorry but we need to wait for ffdshow fix.

As for new build - it just gives better quality then the previous build :)

Radek

[Emp3r0r]

I saw the noise too but I thought it was some fluke with the ffdshow applying the noise even though I had it turned off. What I also noticed was that when seeking in VirtualDub there is no noise but when you hit play, it appears. It simply looks like post processing to me. I like the post-processing noise so that is why I chaulked it up to ffdshow rather than xvid. Anyway, just my 2 cents.

[iago]

@sysKin and Koepi,

Yes, once more many thanks for your great efforts! :) Since it's begun to get a bit complicated to follow the threads and the information provided in those threads about QPel (and B-frames), I'm just trying to summarize the current situation as I get it. (Please correct me if I'm wrong!) :

* QPel (and B-frames) features should be working quite well at the moment with both Nic's 11/10/02 build and Koepi's 12102002-1 build. Regarding QPel, Koepi's latest possibly can give better results since sysKin's some bugfixes are applied as well.

* The problems to occur with QPel are mostly player and/or decoding filter related.

* (When using B-frames it's a good idea to enable "DX50 B-VOP compatibility" to get better results. To playback an encode with B-frames we can use ffdshow at the moment.)

* For playing back QPel encodes we'd better not use ffdshow until a fix is applied, and use Nic's DSF (?).

regards,
iago

[MaTTeR]

Hi Emp3r0r,

Any chance your using Win2k? How about Koepi's YUV patch? I honestly don't see this noise problem at all in Vdub. It's definitely showing during playback or even paused with the above mentioned players though.

@Nic

I sent you a PM with a link to download a short clip for testing. Let me know if you need any other information.

[cult]

qpel plays fine with my zoom player and ffdshow if I enable use xvid.Otherwise I get some strange colors appearing on the screen.

[MaTTeR]

Originally posted by cult
qpel plays fine with my zoom player and ffdshow if I enable use xvid.Otherwise I get some strange colors appearing on the screen.

I've seen that issue too but that is a known problem. The noise problem is something totally different here though.

I'm starting to think this is some sort of problem related to Win2k. I just installed WinXP on another system here and I don't see any of the noise problems on it. So far the noise artifacts are only on my two Win2k systems. I'll test it on my laptop later which is running Win2k as well.

[cult]

forgot to say...I am with w2k...No noise here

[Emp3r0r]

@Matter: Ya, it was the win2k machine at work, havn't tested on my winxp machine at home.

[Acaila]

I believe I'm also seeing what MaTTeR is describing.

It's extra noise mostly around moving objects. Kinda reminds me of DivX3, you know noise/block trails when something moves fast or the camera pans from one side to the other.

It's visible in TCMP, WMP and VDub so I doubt it's a directshow problem.

I'm on Win2k also, but I fail to see how that could be the cause...

Ps. Same settings I posted here earlier. Though the block artifacts I saw before haven't repeated themselves. This noise is much subtler, but still very visible.

[MaTTeR]

Grhh! Seems to be working fine, it's my mind that isnt. Disregard the comment about ModulatedHQ please.

@Acaila,
It(noise) might not be Win2k related but it's definitely more visible when viewing on TV out here. If you turn the brightness up from the Xvid DSF then it becomes very apparent. Now that you mention I do tend to see it more apparent in motion frames. Maybe it's not Win2k but a difference in overlay color/brightness differences between all the machines here(darker the overlay colors are, the less I'll see the noise).

[unplugged]

Originally posted by Koepi
New build up at my site, incorporating sysKins bugfixes committed a few minutes ago.
Committed to CVS? :)
So, has Nic's 13/10 compile this important bugfixes too?