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chroma noise reduction??

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Anonymous
February 5, 2005 4:32:27 AM

Archived from groups: alt.video.laserdisc (More info?)

does anybody know of a good method to reduce chroma noise reduction?
preferably some sort of analog box i can use on the TV but software would
be great too!

anybody know anything about this, or will i just have to get a good
laserdisc player? lol... man i hope not, i couldn't afford a REAL good one
right now.

thanks!
-Mike

More about : chroma noise reduction

Anonymous
February 5, 2005 10:22:27 AM

Archived from groups: alt.video.laserdisc (More info?)

On Sat, 05 Feb 2005 01:32:27 -0500, "half_eaten"
<half_eaten@nospam.yahoo.com> wrote:

>reduce chroma noise reduction?

Uhh...

>preferably some sort of analog box i can use on the TV but software would
>be great too!

AviSynth kicks ass.
Anonymous
February 5, 2005 10:45:39 PM

Archived from groups: alt.video.laserdisc (More info?)

On my HLD X9, if I want to "reduce chroma noise reduction", I just turn
of the digital video noise reduction altogether!
Kevin
Related resources
Anonymous
February 6, 2005 10:46:57 PM

Archived from groups: alt.video.laserdisc (More info?)

Come on you guys know that's a typo. I'm not that stupid!
Anonymous
February 6, 2005 11:03:24 PM

Archived from groups: alt.video.laserdisc (More info?)

I was thinking of programming my own software to attempt to take care of
this.. could average the frame to the left and right of that pixel with
the pixel in the middle and mix them together at a ratio determined by the
color strength of that pixel.

for example if there the color isn't very strong, it won't blend much at
all, but if it's say a VERY bright red or blue it would mix the pixels
together quite a bit. this should smooth out chroma noise. plus since LDs
are only 425 pixels horizontal resolution this wouldn't cause too much
loss of sharpness.

what do you think?
-Mike
Anonymous
February 7, 2005 7:01:22 AM

Archived from groups: alt.video.laserdisc (More info?)

On Sun, 06 Feb 2005 20:03:24 -0500, "half_eaten"
<half_eaten@nospam.yahoo.com> wrote:

>I was thinking of programming my own software to attempt to take care of
>[chroma noise]
>
>what do you think?

I think the wheel you're looking for has already been invented. Check
out the AviSynth homepage, and Doom9 -- there are lots and lots of
third-party filters and scripts written that are (no offense!) much
more sophisticated than what you're proposing.
Anonymous
February 7, 2005 7:05:48 AM

Archived from groups: alt.video.laserdisc (More info?)

In article <46882a5be3f335ad36ac936469ba6f60@localhost.talkaboutvideo.com>,
"half_eaten" <half_eaten@nospam.yahoo.com> writes:
> I was thinking of programming my own software to attempt to take care of
> this.. could average the frame to the left and right of that pixel with
> the pixel in the middle and mix them together at a ratio determined by the
> color strength of that pixel.
>
> for example if there the color isn't very strong, it won't blend much at
> all, but if it's say a VERY bright red or blue it would mix the pixels
> together quite a bit. this should smooth out chroma noise. plus since LDs
> are only 425 pixels horizontal resolution this wouldn't cause too much
> loss of sharpness.
>
You are considering an ah-hoc (not necessarily bad) nonlinear digital
filter. If you have had some training in digital filtering, I'd suggest
doing a little more research, and also doing some 3D filtering (doing
some frame averaging.) All of the filtering techniques should likely
take advantage of some nonlinear processing (changing the amount of
filtering or averaging based upon signal characteristics.)

You can do a reasonably good job without a theoretical background.
If you use several techniques, you might get a 3dB (or maybe more)
noise reduction. If you use several high power techniques, you might
be able to get alot more... When I use lots of NR (both SW and HW),
I can do a capture that looks ALMOST like a 'soft' DVD from an
LD... (The resolution is like a very good LD, and the SNR is FAIRLY
CLOSE to a moderately good DVD, with very good detail but very low
HF noise.)

Being more specific, what you are doing is doing 2D filtering, and the
video signal is already significantly filtered in the HORIZONTAL
direction, but there is some potential benefit in the vertical direction
(especially if you do the averaging between fields -- directly adjacent
lines, and mitigate SOME of the loss in vertical resolution.) This entails
a delay that is a full field (because adjacent interlaced lines are actually
the full field time away.) If the two fields are very different, then they
shouldn't be averaged. If the difference is between fields minimal, then you
can do significant amounts of averaging without too much damage.

Avoid the RGB domain for most of your filtering and look towards the
Y-Cb-Cr type domain or HVS (if you are a little more aggressive.) Frankly,
you might be able to take advantage of working in both domains.

John
Anonymous
February 7, 2005 7:09:46 PM

Archived from groups: alt.video.laserdisc (More info?)

Thanks for the tips guys, I'm going to starting doing some programming
tonight and start with what I was talking about, and once that part's
done, I can take some of these other ideas into consideration and see how
well some of these different methods work out.

I have a couple LDs here that have TERRIBLE chroma noise but are good
movies and I wanted to fix it as much as I could.

-Mike
Anonymous
February 8, 2005 7:33:03 AM

Archived from groups: alt.video.laserdisc (More info?)

In article <fqpd011kvv54cept77el4mnpbug042bnr1@4ax.com>,
Karyudo <karyudo_usenet@yahoo.com.remove.me> writes:
> On Sun, 06 Feb 2005 20:03:24 -0500, "half_eaten"
> <half_eaten@nospam.yahoo.com> wrote:
>
>>I was thinking of programming my own software to attempt to take care of
>>[chroma noise]
>>
>>what do you think?
>
> I think the wheel you're looking for has already been invented. Check
> out the AviSynth homepage, and Doom9 -- there are lots and lots of
> third-party filters and scripts written that are (no offense!) much
> more sophisticated than what you're proposing.
>
It is pretty clear that he wanted to try to learn a little. Of course,
those who have alot of programming (and DSP) experience will do much better
:-).

John
Anonymous
February 8, 2005 9:18:10 AM

Archived from groups: alt.video.laserdisc (More info?)

On Mon, 07 Feb 2005 16:09:46 -0500, "half_eaten"
<half_eaten@nospam.yahoo.com> wrote:

>Thanks for the tips guys, I'm going to starting doing some programming
>tonight and start with what I was talking about, and once that part's
>done, I can take some of these other ideas into consideration and see how
>well some of these different methods work out.

If you're into programming, then AviSynth is probably even more
logical as a place to start! You don't have to write any of the
overhead junk; that's all taken care of. All you have to do is
concentrate on writing up some C (of some flavour) to take care of
your particular CNR problem. Not being a programmer myself or
anything, I can still imagine that you'd be able to pile through
several iterations of a half_eaten_CNR plugin for AviSynth before
you'd even have half the other stuff needed for a standalone app
debugged.
!