Bug with Xvid XviD-1.1.0-30122005 "greyscale encoding" option?

[Fr4nz]

Hello all.

Maybe I've found a bug or something that doesn't work with the "greyscale" encoding option in xvid 1.1 final (build by Koepi).

The sample with the problem is here (the film is "good night and good luck" by G.Clooney, which is a B/W film) which was made with Gordian Knot 0.28.7:

http://users.libero.it/i3ltt/Cazzate%20varie/prova_3.avi

As you will see, the problem is that sometimes you see violet zones in the video. This is clear if you go at 1 min and 23 sec (look at the shoulders of the man).

This problem is present with both Divx and xvid decoders.

Options Ive used with Xvid XviD-1.1.0-30122005 _Final Release_ final are:

2-pass encoding
700kbps bitrate (very low because I was interested at the picture-quality at low bitrates)
vhq=1
adaptive quantization
packed bitstream
b-vops (2 consecutive)
quant type H.263
greyscale encoding
motion search precision 6
use VHQ for B-frames too
use chroma motion
trellis quantization

The problem disappears if I uncheck the "greyscale encoding" option, so there must be something that doesn't go with it..

Maybe someone could investigate the problem...

EDIT: Link to the original VOB clip: http://www.chronocrossdev.com/sources/xvid_purple_source.zip

Bye
Fr4nz

[ChronoCross]

Please provide the source clip. Thank you.

[Fr4nz]

Where I can upload it? I don't have enough space cause the source is from a DVD, so I'd need some tens of megabytes...

EDIT: I have ICQ, so if someone has some webspace please contact me via PM.

[BigDid]

Where I can upload it? I don't have enough space cause the source is from a DVD, so I'd need some tens of megabytes...
Hi,

From the general discusssion main thread:http://forum.doom9.org/showthread.php?t=96362

Plenty of choice
Always good to :search:

Also your uploaded clip does'nt need to be "tens of megabytes", [edited] see additional post below

Did

[communist]

Excuse me but where did you get the DVD from? According to amazon.com it will be released in March.

[Fr4nz]

Excuse me but where did you get the DVD from? According to amazon.com it will be released in March.

Here in Italy it's already out. See here for example: http://www.videoplay24.it/idp.php?id=8369

[Fr4nz]

Hi,

From the general discusssion main thread:http://forum.doom9.org/showthread.php?t=96362

Plenty of choice
Always good to :search:

Also your uploaded clip does'nt need to be "tens of megabytes", again use search :)

Did

I'll upload the clip (93 megs, VOB) as soon as I can.

[communist]

These release schemes get weirder and weirder.. in Germany it hasnt even been in Cinemas and wont be for another few months :|

/EDIT Ah yes there is a (very) light violet tint for a few second (decoding with ffdshow20041012).

/EDIT2 I cant reproduce that bug with other sources, are you sure its not in the source (ie DVD / avs)?

[BigDid]

I'll upload the clip (93 megs, VOB) as soon as I can.
Hi,

I knew I should have been more specific, sorry about that, I edited my previous post in that sense.

My meaning about tens of megabytes was related to : bigger the size less the downloaders :o

93megs beeing quite big If you divide the size by 10 maybe you could get ten more downloaders? :)

If you don't own a Vob cutter something like mpeg2cut or mpeg2schnitt could do it.

Did

PS: Going to hibernate until end of february except, maybe, for exceptions :)
Bye

[ChronoCross]

If I download it I'll mirror it.

[Fr4nz]

These release schemes get weirder and weirder.. in Germany it hasnt even been in Cinemas and wont be for another few months :|

/EDIT Ah yes there is a (very) light violet tint for a few second (decoding with ffdshow20041012).

/EDIT2 I cant reproduce that bug with other sources, are you sure its not in the source (ie DVD / avs)?

The source is OK, in fact if I disable the "greyscale encoding" option the encoded file is ok.

@ Bigdid and Chronocross: check your user CP!

[sysKin]

If the film is already black&white, what's the point of using grayscale in xvid?

[Fr4nz]

If the film is already black&white, what's the point of using grayscale in xvid?

From Doom9's guide ( http://www.doom9.org/xvid-vdub-11.htm )

"Greyscale enables a mode optimized for greyscale (black and white) content. It discards all information from the U/V plane (that's where color information is stored) and you end up with a black and white picture."

That's why.

[sysKin]

From Doom9's guide ( http://www.doom9.org/xvid-vdub-11.htm )

"Greyscale enables a mode optimized for greyscale (black and white) content. It discards all information from the U/V plane (that's where color information is stored) and you end up with a black and white picture."

That's why.

OK the first sentence is incorrect.... in fact grayscale doesn't even make encoding any faster (it could).

[Fr4nz]

OK the first sentence is incorrect.... in fact grayscale doesn't even make encoding any faster (it could).

Yes I noticed the encoding was slower...

Anyway you're saying that "greyscale encoding" option is useless when encoding B/W content?

EDIT: In the meantime I've uploaded the original clip to Chronocross, who should put it in a mirror soon.

[sysKin]

Yes I noticed the encoding was slower...Should be the same.
Anyway you're saying that "greyscale encoding" option is useless when encoding B/W content?Yeah, if a movie is already black and white then this option doesn't do anything (except possibly causes problems).

[Fr4nz]

Should be the same.
Yeah, if a movie is already black and white then this option doesn't do anything (except possibly causes problems).

So are you saying the "violet phenomena" is normal?

[ChronoCross]

Sorry just woke up 5 mins ago.

http://www.chronocrossdev.com/sources/xvid_purple_source.zip

Edit changed the url: making my webserver more organized.

[Fr4nz]

Any news about this?

[Boulder]

Yeah, if a movie is already black and white then this option doesn't do anything (except possibly causes problems).
Actually many movies are not b/w even though they look like that. You can check this with ColorYUV(analyze=true).

XviD problems can be avoided by using Greyscale() in the avs script.

[LordIntruder]

Hello all.
As you will see, the problem is that sometimes you see violet zones in the video. This is clear if you go at 1 min and 23 sec (look at the shoulders of the man).


Hi,


Sorry but for me everything's fine, even at 1'23". I only have Xvid 1.1 official and Divx latest version up to date. No ffdshow on my machine.

If everything is ok for me, I would suspect a conflict with codecs or stuff like that.

By the way me too I followed (and still today) doom9's advice and I encode Black and White movies with the Xvid grayscale encoding option. It's always fine and I never see someone complaining around me.

[Fr4nz]

If everything is ok for me, I would suspect a conflict with codecs or stuff like that.

That's impossibile, before installing Xvid 1.1 I didn't have older versions installed.