The VideoEq -- A low cost external grayscale/gamma/cms tool - Page 21

What I mean is that if you display an 8-bit source on a CRT and send that same 8-bit source to any modern consumer-grade display (that I have seen) there is a noticeable increase in posterisation (banding/discolouration) in the image which can be very distracting at times in my opinion.

It can't be avoided with DLP & Plasma due to how they work, and I've yet to see an LCD or LCoS-based display that doesn't posterise the image. Even if there was an LCD/LCoS display out there that didn't posterise the image, there are too many other issues with the image quality on those display types for me. (motion handling for one thing)


Some displays claim to have 10-bit panels (most LCoS displays now for one thing) and certainly I can believe that sending them a 10-bit (or greater) input will result in better gradation, however I am not yet convinced of the resulting image even being transparent to 8-bit when doing so. Even if the panel is 10-bit addressable, you're going to be throwing away a lot of precision for the greyscale, gamma and colour correction that these displays require.

With a good CRT this correction is done in the analogue domain by altering the voltages sent to the guns which does not compromise image quality. With a CRT like mine though, a LUT is required to maximise contrast and have a truly flat greyscale & gamma. This has the downside of introducing ugly posterisation artefacts into the image, though it's still not as bad as I've seen on any modern displays.

I'm sure there will be some improvement going from 8-bit to 10-bit with the VideoEQ, but I haven't seen anything showing how much of an improvement that is, and as I mentioned in my last post, I'm not convinced that it's going to be worth a $400 investment for me to find out.


Believe me, I'd love to be happy with a modern display. CRTs are a huge pain and there's a lot to like about flat panels or other non-CRT displays, it's just that the image quality is not up to par yet in my opinion, and it looks like it's going to stay that way at least until OLED comes along, if that even fixes things. (probably not) I was actually banking on FED/SED, but it looks like both of those are dead nowat least for consumer displays.


With regard to chroma subsampling, it's simply not possible for it to be visually lossless due to the fact it's half the resolution. Whether or not the scaling is done in a linear colour space has no effect on that. (but will affect how good the end result looks)

I have the RS1u and as long as I get greyscale as close as I can on the RS1 then use the VideoEQ I don't have excessive banding. If my black level is off I may have some banding down in the lower IRE's but for the most part banding isn't an issue for me and I use 8 bit in and out. The CMS doesn't cause any banding at all. I had been using a Lumagen HDQ for grey scale and gamma and when I first got the VideoEQ I used it for gamut only and it was very clean. Again 8 bit in and out. I can see some slight stepping in a grey ramp but I see that without the VideoEQ in the path. Unfortunitely I can't send my projector greater than 8 bit using RGB or 4:4:4. I tried 4:2:2 and didn't see any difference. The RS1u is only HDMI 1.2a compliant.

When i had the HDQ if I didn't adjust the RS1 first I did see more banding but when you get it balanced just right it will be so minor that you never see it on the screen with real material. At leasts thats my experience calibrating with 8 bit only.

Andrew, I do think the banding is made a lot worse by gamma not being set correctly. A CRT display will have a better gamma correction curve by default simply because it's inherent of how it displays images. It is not so with digital displays. Some banding may also be present because of the compressionist did not take extra care and is introduced by the video compression being used.

Well, about chroma subsampling not being visually lossless, I think it really depends but at normal viewing distances, it is visually hard to detect IF done in linear space. When done on an already gamma-corrected image, it's going to push some colours of gamut and therefore introduce very visible and nasty errors that look like colours bleed into each other with a black/dark overlay. I can't explain it any other way. The colours may still bleed somewhat if done in linear space but you will not notice it at normal viewing distance, because the out of gamut errors are not there. There are some excellent algorithms now to recover the lost colour information, too. There is a huge difference when I send the original 8bit signal to my JVC and when I let my Pioneer do so using deep colour at 36bits (12bits). The colour upscaling is impressive especially on blu ray when done by the Pioneer, but it doesn't show itself as less/more banding, just a higher colour resolution. Banding is indeed there on some material if gamma curve is not smooooooooooooooth. The JVC has a few gamma settings and some of the slopes exagarate banding while others make the image even on DVDs look like I'm watching an optical print. I do think lots of the digital displays are crap in this regard, though.

As a bottom line, check out a properly calibrated JVC projector from their HD (RS in the US) line and then tell us how crap digital displays are. )

IIRC Andrew is UK based and he bought (and sold) a Sony HW10 projector, so maybe he is just more demanding than we are. I don't know how well the HW10 compares to the JVC HDxxx range, but Andrew mentions he doesn't like the motion issues with LCOS, so even as a HD350 owner myself I have to conceed that some people are troubled by this.

Thankfully I'm not troubled by motion issues or banding myself, but I am bothered by DLP rainbows, so each to there own I guess.

That's right, I did have an HW10. I was quite happy with it at first, though over time the motion handling started to get to me. That's my problem with a lot of these modern displaysI might be OK with them at first but after a few weeks things I thought I would accept start to bother me more.
Posterisation was there but I expected it when I bought the projector and I was weighing out image size & cost vs image quality and thought the HW10 was a good compromise.

If it had been OK I might have stuck with the HW10 for a while (but I'd be itching to upgrade nowone of the issues with modern displays in my opinion) however the projector developed numerous faults within the first 6 months and Sony's premium' 3 year support service refused to repair it and tried to claim that some issues like the lens not staying in focus were normal. I had to refocus every 45-60 minutes the projector was on for the image to be sharp even after giving the projector plenty of time to warm upif you focused right at the beginning of a film, it would be out of focus by the end.

They claimed that there was too much dust on the filter (not inside the projectoron the dust filter) despite the fact that the projector room had an air filter running in it 24/7 and the projector was maintained as the manual instructed.

They said this caused it to overheat which I don't believe to be the case at all as there would have to have been at least three different failings in the projector to have allowed that to happen, in which case the thermal protection features of the projector were faulty and it should still have been covered.

On top of that, the gloss black finish was completely ruined when the projector was returned to me, which they claimed was like that when I sent it in, despite the fact that I had taped a note to the top of the projector and anywhere that had tape on it (they left it on) was undamaged.

Needless to say, after that I promptly got rid of the projector and plan on avoiding Sony products in the future where possible. (but if they happen to be the first/best with OLED I'll need to make an exception)

I know it's getting more OT, but I can totally understand your reasons for getting shot of the HW10. However, I really would recommend seeing the newer JVC models (especially if you wait until the launch of the next range, if you prefer an end of line deal). The HW10 uses a dynamic iris IIRC which the JVC doesn't, not sure if this might make any difference one way of the other.

As for focus drift, I usually check mine after 20 minutes warm up ( about the time it takes to set up my room 'tent' and get everything else ready) and I've not seen it change after that. Even my old AE3000 only needed a tweak after the first 20 minutes or so, which makes me think your HW10 was a poor example, despite Sony's lack of assistance.

I'm intending on recalibrating my setup in the autumn as I'll be renting an i1Pro with a Chromapure licence for a week. It'll be interesting to see how my results compare to using the supposedly less accurate (especially for colour gamut work) i1LT I currently use.

I kind of have to agree with Andrew on the motion issues. It is noticable only if an object moves at a medium pace sideways, though, and shows up as banding. Yuk. DLP is very much better at motion. DLP is also better at keeping detail on moving objects.

At the same time, the deeeeeep blacks and amazing 3D image makes up for the above.

You know I'm not sure if it's only the consumer version of LCOS that has these problems, as I recently went to see a movie in a cinema with Sony SXDR and I didn't see any of the motion issues. It could also have been the material as it shows up very rarely. :S

I just wanted to add that I have owned various projectors over the last 6 years and my JVC DLA-HD350 beats them all. On top of that - after having calibrated it properly with a VideoEQ for HD and Pal gamut, it beats my friend's HD550 and I thought that looked amazing when I first saw it and bought mine because of that viewing. Having accurate colours I think goes a long way to creating that 3D image. I'm regularly amazed at the image quality now.

Having said that, I'm sure I could get better, but ignorance is bliss in this case, as I'll be happy with it for a few years I think.

I am compiling some screenshots with and without VideoEQ engaged on my HD350. Is anyone interested to see these? If so, I can post them here.

I'm interested. Curious to see what kind of difference it makes on other displays. If I get around to it I'll take some photos as well.

I'd be interested as well. Could you also post before and after reports?

I had posted reports in this thread before, just have not gotten around to taking pics of results.

Yes, I saw them, thank you. But you used it on a Pioneer, which is pretty damn good already. I'd curious to see rollon's results and ideally, I'd like to see the results on a panel with poor gamma.

Anyone use the VideoEq on a panel (such as a 2-3 yr old Panasonic) with poor total light output in Cinema mode, or in Standard mode with decent light output but with poor gamma?

Were you able to improve light output in Cinema mode and still achieve linear gamma, or were you able to keep the light output in Standard mode and strighten gamma? Is having limited light output the only way to achieve good gamma on my panel, or can you have both utilizing the VideoEq on a Panasonic?

I'm getting 27 ftls in Cinema, but would love to get 33-35 ftls

Been tossing back and forth on whether to get one for my 58PZ700U and hold off replacing it for a few more years, or just put the money towards a replacement display sooner.

you won't be able to up the light output for cinema, but you would be able to flatten the gamma curve for standard.

Will flattening the gamma curve of standard also reduce light output, resulting in cinema light output?

No it won't.

The way a LUT table works is that the end points are essentially fixed (all though they can be brought in towards the middle) and you can raise or lower the points in between.

The video EQ is an ideal tool for flattening the gamma curve on standard while maintaing the maximum light output. That is exactly the kind of problem it was designed to solve.

Thanks for your response Sotti. I just got off the phone with Rayjr who discussed this with me. I think you both are right, and this might just be the tool I need.

There's 3 in the Classifieds now..

Cool, I'll get around to posting them at the weekend probably. I just need to take some more and sort through them.

Thanks,, I saw them. I'm going to try and find the best deal I can find on a used standard model, since I don't need four custom modes.
-John

I have taken some pictures from Mission Impossible III on Blu Ray. I have also taken some of Cars, but they didn't come out right and representative of what you can see on the screen. I think it's because I left the lights on for MI 3 while for Cars I turned the LED lights below the screen off so the camera overblew the images.

Anyway, I have attached the pictures from MI III to this message. You can clearly see what difference it makes to have the VideoEQ on in terms of - what looks like - colour saturation. It's not actually simply colour saturation, but the gamut. The picture gains a lot better dimensionality and very precise colours like you'd see in the cinema (well, almost). The camera is not a 100% accurate but you can use the pictures to compare them to each other. The movie looked amazing on the projector. Apart from some pretty steep shadow delineation near blacks which makes darker scenes lose dimension compared to some better transfers. The funny thing is that the JVC makes picking these things out very easy and only something like 1 out of 20 reviewers of this Blu Ray actually picked up on this. I checked to make sure I was not imagining things. I don't like it when I can't see into the shadows. Makes me uneasy. But without joke, these "high contrast" transfers do annoy me.

I'll upload some more as I take them. I do want to show you a Pal DVD as well, because there the problem is even worse if you have an uncorrected gamut. NTSC... well, there was no hope for that one to begin with so won't bother.

Btw, best way to compare...

Open image 1 then click on the image to open in new window/tab
Open image 2 and do the same
Flick between the tabs to see the difference
Now repeat with the second pair.

Your colour memory is not that great. I know mine isn't.

"Thanks,, I saw them. I'm going to try and find the best deal I can find on a used standard model, since I don't need four custom modes.
-John"

That's probably a good decision. I have a Pal gamut dialled in for mine and there's not much difference between it and HD on normal material. The only place I saw it made a difference is on scenes with lots of magenta or very saturated reds. Even though green is most out if you look at the chart?! Strange, eh? :\\

I didn't see the chart

"I didn't see the chart"

I never posted it. Would you like me to post the charts for both the HD and Pal gamut dialled in?

Btw, I meant the CIE chart. If you look at the green on the CIE chart for HD and then Pal, you can see that the green is the biggest difference. The other colours are not so much. I guess the secondaries will be different as well, especially magenta.

Mmm.. I just answered my own question... why is magenta so noticably different between the two? Because green affects the secondary adjacent to it. Ta da. I can be so dumb sometimes. :P

Not necessary, I just thought I missed something.




My biggest goal was to correct yellow secondary and blue primary, (If I stuck with cinema - 26ftls), as I was able to get Red, Green, Cyan, and Magenta pretty close; or straighten gamma and correct the color gamut in standard/custom modes to take advantage of the increased light output of theose modes on my Panny 58PZ700U.

The other option is to wait and see what Kuro technology gets incorporated in the Panasonic 2011 or 2012 models, and upgrade to 65". The money not spending on a VidEq would bring me 25-30% closer to a replacement, and then sell my PZ700U

I took a couple of cell phone pics with my new Samsung Vibrant. While cropping in the phone the resolution apparently got lowered, but you can still clearly see the difference in color saturation. Neutral settings on the left, right shows settings calibrated from Oppo Blu-ray player and I'm using the same settings for DirecTV.



For me the Pro model is rather necessarly since I also have a HTPC and that unit has a much different setting compared to Oppo so the extra custom settings plus the ability to use remote to flip between them is very convenient. I've programmed my Harmony to send out the Custom signals to the device on the Activity buttons.

I guess a Pro unit makes sense if you have a couple of sources you need to dial in. In my case, I only use a Blu Ray player and the xbox 360. The 360 looks close enough to the blu ray player that I don't bother with it. If games were also made with dialled-in equippment like movies are then we'd have more of a chance to see what they intended them to look, but obviously that's not the case so whatever. I guess THX games are an exception.. the 5 out of 1000s that are on the market.