Please Help with strong colours and DVDx quirks

[xs-269]

Hi

I've been searching for a while now....and can't find any anwsers....I really need some help...

1) When encoding with Xvid I find that I get really good results....but when I get colours in strong Reds, Greens or Blues the areas seem to appear as if they came from an interlaced source...how can I get rid of this??...could it be because of the RGB?? or a decoding filter??? (using Koepi's latest build and ffdshow)

2) Sometimes..(not always) when using DVDx I get to the point when the source image should be displayed and my PC freezes....with red dots all over the screen...(sometimes they're green). Could it be the graphics card?? It never used to happen before...now it happens all the time!! Any ideas??

Thanks...I could really use some help :confused:

;) :) ;)

[Koepi]

Welcome to the board, xs-269,

before I answer your questions I'd like to remind you that a subject/topic should have a short summary of your post, i.e. "need help with strong colours and DVDx quirks". Then people will see if they can contribute to that field or not - and don't ignore the post that says "i have something so abstract here" - which makes most people think that it's so complicated that they can't help at all ;)

Ok, long introduction blah, to the questions:
1) You're using RGB as source? Head over to the avisynth forum and read about "YV12" and build a YV12 process chain. This should soften your problem quite a bit.
You can also try to activate xvid's chroma optimizer. It interpolates chroma in bright/dark areas so the aliasing artefacts (which result from chroma beeing only half the resolution of the luma plane - usually unnoticable to the human eye...) will be softened as well.

2) Your computer isn't overclocked by any chance? Or your graphic card? When I played around with my old vga card and overclocked it a bit too much, the computer froze with an image like you describe. Anyways, whatever is wrong there, it's definatly not xvid related, it's either overclocking or a problem with DVDx, in this case you have to contact the author of DVDx.

I hope this helps,

regards
Koepi

[xs-269]

Thanks a lot Koepi...

As you can see it was my first post. Thanks for the pointers...if you don't mind I would like to use your example for the subject heading ;)

Thanks for the help...I'm gonna look into it right now and see if I can resolve some of this. You probably correct about the YV12...I can't remeber exactly which option I was using (haven't been able to get that far in the program to view the options in a long time) but I remember that I didnt use RGB 24 or 32

I don't overclock either processor or video card...so its probably something wrong with DVDx...I just find it strange that it only now started to do this....when it had been working well for many months...(possibly a conflict?!?!)

Many thanks Koepi :) ;)

[mf]

About the interlaced effect: you most likely have a telecined source, and the chroma (color plane) is upsampled incorrectly. The chroma stays interlaced during your deinterlacing/IVTC process, and is treated as progressive at the end of the playback chain (when it is eventually converted to RGB since a computer monitor can not display YUV colors, be that done by your video player, directx, display driver or videocard), causing the chroma to be on the wrong places causing this "blunt interlacing" (chroma is subsampled so the interlace artifacts will be "bigger", that is 2 pixels high instead of 1). If you're using avisynth, this is best solved by performing IVTC with Decomb, which will convert the chroma to progressive properly. Either that, or see if you can use DVD2AVI's "force film" mode for IVTC. Be careful though, it can cause problems. Doom9's guides give more clarification.

[xs-269]

Thanks guys for all the help...

I'm gonna try an encode this evening and see if anything improves...and will probably avoid using DVDx from now on :sly:

Thanks once again :) :) :)

[dragongodz]

if your colours are too strong you can use the luminance control(in input settings) to make some adjustsments to that. if you see interlacing lines in your encodes then you simply turn on deinterlacing (also in input settings), not terribly difficult.

the general rule for freezing part way through is overclocking or bad memory. not DVDx's fault in those cases obviously.

[bond]

hey koepi, long time not around at doom9 :) too busy?

[Koepi]

Hi Bond,

i was on holidays for 3 weeks in Istanbul. Returned last sunday and still have to catch up with work and so on. But I'm around, be assured *eg* ;)

Thanks for noticing the absence :)

Best regards
Koepi

[xs-269]

Well Guys...(at least some good news!!)

I was able to do an encode without any problems using Gordian Knot...(had a couple of problems fisrt time round...but reinstalled and it worked just fine) :D

Could be a problem DVDx or the way it accesses the image source...but with Gordian Knot I had no problems...so I doubt its memory or processor.

Unfortunately the source I used didn't have any regions with bright colours...so I haven't been able to analyze that yet...so I'll get back to you guys on that one (hopefully soon ;) )

Thanks Guys :) :)

[mf]

Just tweak up the saturation and you'll have strong colours all right :D.

[Hectic]

this has nothing to do with interlaced video or anything. i asked the same question a while back. i described the colors as blocky. however i didn't let it bother me for very long since i just watch all my movies on my tv screen and i can't even notice it on my tv. i did try changing the colorspace to rgb in dvd2avi and i think it helped a little bit so you might want to try that..it didn't get rid of the problem but it made it a little less noticable. maybe try that as well as the chroma optimizer koepi suggested. i just encoded a roger waters (from pink floyd) concert and of course it's filled with nice greens and reds and neon colors...how the output avi looked is almost comical:p

[mf]

Originally posted by Hectic
this has nothing to do with interlaced video or anything. i asked the same question a while back. i described the colors as blocky. however i didn't let it bother me for very long since i just watch all my movies on my tv screen and i can't even notice it on my tv. i did try changing the colorspace to rgb in dvd2avi and i think it helped a little bit so you might want to try that..it didn't get rid of the problem but it made it a little less noticable. maybe try that as well as the chroma optimizer koepi suggested. i just encoded a roger waters (from pink floyd) concert and of course it's filled with nice greens and reds and neon colors...how the output avi looked is almost comical:p
Sigh. MISINFORMATION. xs-269 is clearly describing interlaced artifacts, so we believe him. There is a source to this problem. Nice of you to notice your "problem" is SIMILAR to his, but it's not the same. His is fixable, yours is inherent to the format. So thanks, but your "advice" really wasn't needed.

[xs-269]

Well... after much work and studies (still got exams ongoing :rolleyes: ) I've managed to slighty reduce the problem but not eliminate it!

I did some homework and have noticed that some samples of movies off the net encoded with Xvid seem to show the same issue on my PC...the images are not interlaced nor the sources...only in the areas of the bright reds, greens, and blues does the image appear that way!! I have a feeling that it could be more a problem with my ffdshow filter (configuration) or maybe screen resolution?!?! :confused:

I can't remember exactly...but I think that on a friend's PC he didn't get this problem....and the file was the file that I had encoded...

Any more ideas guys???

Thanks :cool:

[sysKin]

I also have ugly chroma artifacts - if I enable YU12 overlay in ffdshow.
Chroma is moved relatvie to luma (to the left if I remember) and there are some weird stuff on the left of the screen with some movies... looks like sawtooth edges or something.

Anyway, I just disable YU12 and am happy :>

Radek

PS I have nvidia geforece2mx400

[Soulhunter]

@xs-269

Try to put "ConvertToRGB32()" to ffdshow's Avisyth-tab...

Bye

[Hectic]

Originally posted by mf
Sigh. MISINFORMATION. xs-269 is clearly describing interlaced artifacts, so we believe him. There is a source to this problem. Nice of you to notice your "problem" is SIMILAR to his, but it's not the same. His is fixable, yours is inherent to the format. So thanks, but your "advice" really wasn't needed.

oh man, it's people like you who make me blow up and say things that could get me banned from forums. i'll keep my cool though. look, he's NOT clearly describing an interlaced source hence the fact that he says everything except for the friggin bright colors look beatiful. as a matter of fact, he's clearly describing the color compression issue and has nothing to do with field format.

edit: and the only reaon he even used the word "interlaced" is because the edges of the areas with bright colors look jagged, therefore they resemble interlaced video.

[mf]

Then our xs-269 wasn't very clear. Because
http://mf.creations.nl/yv12chroma/jaggedchroma.png
is clearly distinct from
http://mf.creations.nl/yv12chroma/interlacedchroma.png.

As I said before, jagged chroma can't be "fixed", only smoothed out at playback (as Soulhunter suggests). Interlaced chroma on the other hand has to do with something going wrong in IVTCing.