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Chroma Bug question.

Sessen Ryu

Active Member
I have very little understanding of this chroma bug - but am I right in thinking that this only effects people using progressive scan on a projector or such like?

I have a Denon DVD 2800 and will be using it with a Panny 100Mhz TV - will the bug effect me.....?

cheers for any help
 
Z

zcaps57

Guest
Some devices mask it, some don't. I've seen it on Sky boxes let alone DVD players.
The "chroma bug" only applies to progressive-flagged material (i.e. films). For example...in video-flagged dvd material, there are always the kind of ugly-looking chroma artifacts we associate with the chroma bug. But in this case, it's not a bug, it's just a fundamental limitation of 4:2:0 encoding with interlaced material.

I wouldn't call it the chroma bug the one you saw on Sky boxes.

Faroudja based progressive scan dvd players can mask it to a certain degree because Faroudja features a "chroma filter".
For example Silicon Image (SiI503, 504) cannot mask chroma upsampling error because they simply don't have chroma filter as Faroudja does.
 

Nic Rhodes

Well-known Member
Originally posted by zcaps57
Silicon Image (SiI503, 504) cannot mask chroma upsampling error because they simply don't have chroma filter as Faroudja does.
but if you have a Denon they can fix it....;)

:(
 
R

RichardA

Guest
The Chroma Bug is caused by poor filtering of the colour information coming off any MPEG based signal. (That includes DVD and Digital TV)

It is virtually impossible to spot on an interlace display (like a direct view TV set) without doing a few tricks.

It is visible on any material irrespective of the 'flagging' - if nothing else simply because virtaully no stand alone DVD players or scalers pay any attention to the flags on the disk anyway.

The Faroudja 'hiding' of the bug on the 3000 and 5000 series is more down to excessive filtering (i.e. softening) of the colour detail than any great secrets. Once the MPEG decoder chip has done it's stuff and come up with the incorrect colour information there is no practical method of removing the bug without destroying colour detail changes.

I've been working with the Chroma Bug for about 4 years (after all i'm the S&W guy who demonstrated it to Stacey Spears as mentioned in the Home Theatre HiFi article) and I've seen it on all sorts of equipment including Sky boxes, ITV digital boxes DVD players etc...

The important thing to remember is that 'Chroma Bug' is not always the same thing and can have different levels of visibility so saying player X has the bug and shouldn't be used is erronous. The nature of 4:2:0 chroma sampling as used in the MPEG schemes of DVD and digital TV means that it is impossible to absolutley remove the effect of the lack of colour information on alternate lines - it's simply a case of how effective the filtering is.

We actually use two machine renowned for having 'the bug' (Meridian 800 and Proceed PMDT) but I have never had an audience spot it or comment on it during one of our demos.

Hope this helps.
 
C

Charlie Whitehouse

Guest
Well said Richard. I think too much weight is being put on this aspect of player performance. There are many others which lead to much more visible effects. We're in danger of turning into total hypochondriacs over the issue! :blush:
 

Sessen Ryu

Active Member
Thanks very much for all your replies. Bottom line for me is -
I ain't gotta worry ;-) !!

Cheers
Phil
 

Nic Rhodes

Well-known Member
Common sense from Charlie and Richard A. Strom in a tea cup comes to mind.;)
 
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