[Donny Bahama]

It turns out that I'm VERY sensitive to dithering. To me, it's like bugs crawling all over the screen. My eyes are (unfortunately) drawn to it and riveted by it. It's an even greater problem for me than rainbows.


Just in case I'm using the wrong terminology, what I'm calling "dithering" is pixels on the screen flipping between two (or more?) colors to represent some color that (presumably) the projector (or source device - and I'm lumping the AVR into "source device", here) doesn't display natively. This results in motion where there should be none. It seems particularly common in dark/shadowy areas of the screen, but the other day I noticed it on a close-up of someone's face - and that was in a commercial theater!


I notice it strongly (along with the rainbows) on my aging Optoma HD72. I also see it on my Dad's new Epson 8350 (though it's more easily ignored thanks to the gorgeous color, resolution and black levels). Both my Dad and I are using fairly low-end Blu-Ray players and older/lower-end Onkyo receivers (though mine is a couple years newer and one model up from his). I don't know whether the BR player doesn't have adequate color depth - or maybe it's the receiver. I'm going to be building an HTPC in the not-too-distant future, so that should eliminate any color depth inadequacies at the source.


My Optoma HD72 is clearly on its last legs; it's on its second lamp and brightness and focus have diminished noticeably. I'll be replacing it with a 1080p projector as soon as I can afford to do so - but I want to make sure that, whatever I get, my new projector will have ZERO dithering.


Any advice or insight will be very much appreciated.

 

[RenStimpy]

People commonly confuse grain in the source with dithering. HD movies shot on film are supposed to have a lot of "motion" in the bright areas of the picture. That is what your "bugs crawling all over the screen" sounds like to me.


To see if it is really dithering, you should pause the movie and then see if you still see the problem. If you don't, then the problem is grain and not dithering. When paused you can still see dithering in dark areas of the screen, but in bright areas you shouldn't be able to see any.

 

[Bsims2719]



Quote:
Originally Posted by RenStimpy /forum/post/20809669


People commonly confuse grain in the source with dithering. HD movies shot on film are supposed to have a lot of "motion" in the bright areas of the picture. That is what your "bugs crawling all over the screen" sounds like to me.


To see if it is really dithering, you should pause the movie and then see if you still see the problem. If you don't, then the problem is grain and not dithering. When paused you can still see dithering in dark areas of the screen, but in bright areas you shouldn't be able to see any.

I disagree. I have seen the same movie on a DLP projector and an LCD projector. One had dithering and the other didn't. I think it's inherent to DLP. On a DLP, when paused it goes away on every movie. One curious question that I have always had. Why is there never dithering on cartoons.

 

[RenStimpy]

If you don't see it when you pause, then it is in the source, and the fact that you can see it is a "good" thing, try to hear me out.


The reason you don't see it with LCDs is that the imager used is not as accurate or as fast as a DLP chip. A DLP projector will show all the detail that is in the source, including the grain. A LCD projector will tend to smear the fine detail in the picture reducing the impact of the grain.


Since a DLP will show all the detail there is, the film grain is very apparent and can turn off some viewers, saying they prefer the "smooth" look of LCOS or LCD. My point of view is that a imaging device should reveal all the detail that is in the source, and should not be hiding it. If the source is grainy, that means in motion the film should look like it is crawling with ants.


Many years ago this was one of the big turns offs I had with the JVC RS-1. On my first viewing I had just come from watching one of the Spiderman films on Bluray projected by a 720p DLP projector, and I remember noticing how grainy the film was, especially in the skies (which I also remember seeing in the theater on a film PJ). But when I watched it on the JVC, the skies were so much more smooth. I couldn't believe how much of the detail in the film was being lost on the JVC, it was showing less fine detail than the 720p projector I had just viewed.


The reason you don't see it on cartoons is that they are not shot on film, and so there is no grain. Since there is no grain in the source, you don't see any on the screen.

 

[LeonZA]

If you remove dithering then you have a bigger problem: ugly banding

I would choose dithering over banding anyday

 

[Bsims2719]



Quote:
Originally Posted by RenStimpy /forum/post/20810143


If you don't see it when you pause, then it is in the source, and the fact that you can see it is a "good" thing, try to hear me out.


The reason you don't see it with LCDs is that the imager used is not as accurate or as fast as a DLP chip. A DLP projector will show all the detail that is in the source, including the grain. A LCD projector will tend to smear the fine detail in the picture reducing the impact of the grain.


Since a DLP will show all the detail there is, the film grain is very apparent and can turn off some viewers, saying they prefer the "smooth" look of LCOS or LCD. My point of view is that a imaging device should reveal all the detail that is in the source, and should not be hiding it. If the source is grainy, that means in motion the film should look like it is crawling with ants.


Many years ago this was one of the big turns offs I had with the JVC RS-1. On my first viewing I had just come from watching one of the Spiderman films on Bluray projected by a 720p DLP projector, and I remember noticing how grainy the film was, especially in the skies (which I also remember seeing in the theater on a film PJ). But when I watched it on the JVC, the skies were so much more smooth. I couldn't believe how much of the detail in the film was being lost on the JVC, it was showing less fine detail than the 720p projector I had just viewed.


The reason you don't see it on cartoons is that they are not shot on film, and so there is no grain. Since there is no grain in the source, you don't see any on the screen.

So if you theory is correct you could shoot a digital home movie with a camcorder, display it with a DLP projector and not see any dithering. It would be as smooth as a cartoon?

 

[RenStimpy]



Quote:
Originally Posted by Bsims2719 /forum/post/20810413


So if you theory is correct you could shoot a digital home movie with a camcorder, display it with a DLP projector and not see any dithering. It would be as smooth as a cartoon?

It would be more smooth than something shot on film, yes. However the compression used in a home camcorder will most likely add mosquito noise to the image, which you will see on a DLP projector. This is similar in appearance to film grain, but not as severe.


Again, this would be something that will be in the source, and you can confirm this by going frame by frame slowly through the video. If you put your nose up on the screen, as you move through each frame you will be able to see the noise pattern in the source change each time. In motion these changes flash quickly on the screen giving the appearance of crawling.

 

[Bsims2719]

I agree with the OP it is very distracting. I sold my HC4000 for that very reason. However I sure miss the pop of DLP. Got a refurb 1080UB. The difference in mosquito noise is night and day. I am hoping that the new DLP LEDs will have less of a tendency.

 

[airscapes]



Quote:
Originally Posted by Bsims2719 /forum/post/20811123


I agree with the OP it is very distracting. I sold my HC4000 for that very reason. However I sure miss the pop of DLP. Got a refurb 1080UB. The difference in mosquito noise is night and day. I am hoping that the new DLP LEDs will have less of a tendency.

You know.. I have been watching my Mitsubishi HC3000 for 1600 hours on a Dalite HP 2.8 screen and really have no idea what you guys are talking about. Now my screen in really small so maybe that is why I don't see it..

When I had the projector ISF calibrated the guy showed me how to set brightness on a DLP projector, just display a 0 IRE pattern and adjust till you don't see the mirrors dance anymore. It is very obvious.. but this is not what you guys are talking about.

Can explain what it looks like?

 

[chumpchange21]



Quote:
Originally Posted by Bsims2719 /forum/post/20811123


I agree with the OP it is very distracting. I sold my HC4000 for that very reason. However I sure miss the pop of DLP. Got a refurb 1080UB. The difference in mosquito noise is night and day. I am hoping that the new DLP LEDs will have less of a tendency.

Sorry a bit off topic, but how did you find the 1080UB compared to the HC4000?

 

[coderguy]



Quote:
Originally Posted by Bsims2719 /forum/post/20811123


I agree with the OP it is very distracting. I sold my HC4000 for that very reason. However I sure miss the pop of DLP. Got a refurb 1080UB. The difference in mosquito noise is night and day. I am hoping that the new DLP LEDs will have less of a tendency.

I do not understand why you thought the hc4000 had too much mosquito noise, as I personally believe it to be one of the better DLP's when it comes to LACK of noise and a film-like image. I no longer own an hc4000, but I had one for several hundred hours and was very impressed by the cleanness of the image.


If you are getting a less noisy image on an old LCD, then most likely it is a source issue in combination with a lack of sharpness of the LCD. The 1080ub's were never known to be exceptionally sharp projectors, and this introduces a smoothing effect. I will say DLP has a tiny tiny bit more of mosquito noise which may exhibit itself in a few scenes, but depending on the contrast and camera work and the source (bluray vs. cable vs. whatever) then you should not even see it from normal seating distance 99% of the time.


As a matter of fact, I found the hc4000 to have less mosquito noise than most LCD projectors. Yes, even LCD's can have what looks like mosquito noise, even if the cause is not the same.

 

[Bsims2719]



Quote:
Originally Posted by airscapes /forum/post/20811695


You know.. I have been watching my Mitsubishi HC3000 for 1600 hours on a Dalite HP 2.8 screen and really have no idea what you guys are talking about. Now my screen in really small so maybe that is why I don't see it..

When I had the projector ISF calibrated the guy showed me how to set brightness on a DLP projector, just display a 0 IRE pattern and adjust till you don't see the mirrors dance anymore. It is very obvious.. but this is not what you guys are talking about.

Can explain what it looks like?

Some people must be more sensitive than others. I see it most in solid back ground colors. Say a movie is shot inside a home and the focus is on an actor. It the back ground would be the walls of the house. To me it looks like the walls behind the actor are moving or shimmering. Its very distracting. The crazy thing is that on a cartoon it is completely nonexistent.

 

[Bsims2719]



Quote:
Originally Posted by coderguy /forum/post/20814177


I do not understand why you thought the hc4000 had too much mosquito noise, as I personally believe it to be one of the better DLP's when it comes to LACK of noise and a film-like image. I no longer own an hc4000, but I had one for several hundred hours and was very impressed by the cleanness of the image.


If you are getting a less noisy image on an old LCD, then most likely it is a source issue in combination with a lack of sharpness of the LCD. The 1080ub's were never known to be exceptionally sharp projectors, and this introduces a smoothing effect. I will say DLP has a tiny tiny bit more of mosquito noise which may exhibit itself in a few scenes, but depending on the contrast and camera work and the source (bluray vs. cable vs. whatever) then you should not even see it from normal seating distance 99% of the time.


As a matter of fact, I found the hc4000 to have less mosquito noise than most LCD projectors. Yes, even LCD's can have what looks like mosquito noise, even if the cause is not the same.

Yes, the HC4000 was the best out of all the DLPs I have had. However it was still noticable to the point it was distracting. To me the 1080UB beats the Mits in terms of noise hands down. However it is definitely less sharp. It's like loosing in one respect and gaining in another. Frustrating.

 

[Bsims2719]



Quote:
Originally Posted by chumpchange21 /forum/post/20813656


Sorry a bit off topic, but how did you find the 1080UB compared to the HC4000?

If it wasn't for the digital noise the HC4000 is the clear winner. It's has a lot of "pop" that the 1080 just can't match.


Personally, the most important thing to me is a clean image when projecting 110". The 1080 produces a very clean image.


I'm thinking about experimenting with post processing to remove some of the noise (ffdshow). Anyone have any experience with post processing in this regard?

 

[airscapes]



Quote:
Originally Posted by Bsims2719 /forum/post/20814447


Some people must be more sensitive than others. I see it most in solid back ground colors. Say a movie is shot inside a home and the focus is on an actor. It the back ground would be the walls of the house. To me it looks like the walls behind the actor are moving or shimmering. Its very distracting. The crazy thing is that on a cartoon it is completely nonexistent.

Just did a search on HC3000 dithering.. from an old AVS forum post..
Compared to the PE7700 the HC3000 has a lot less dithering noise (nearly non existing), which always has annoyed me on DLPs.


Must be why I have never seen it.. but will look closely tonight.