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Used Avia to calibrate plasma but the picture seems dark?

828 Views 12 Replies 8 Participants Last post by  Bob Pariseau
I have a 42 panny ED and I used the avia dvd to calibrate it to ntsc standards.

My question is: day shots look great, but when the picture goes dark, it gets really dark and it is hard to see any details.

Did i do something wrong? or is it supposed to be this way?

it seems that everyones recommendation on picture and brightness to 0 (or low) is really low and is too dim for dark scenes.
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Part of the answer has to do with room lighting. If your room is dimmed the tendency for darker scenes to become murky will be less. Calibrate under your normal viewing conditions, but if your normal viewing conditions are a dimmed room you will likely be happier for a larger range of source material.

My suggestion is you try your current calibration this way for a day or two to give yourself a chance to get used to it using a small set of DVDs you like as samples. Then start making small changes towards raising the levels, taking a few days with each to get used to them again and constantly referring to your chosen test DVDs to keep things grounded. I.e., raise the white levels a few steps, re-adjust the black levels accordingly and leave it that way for a while.

Also it's important to use Avia correctly. You need to calibrate for each source device on each input. If you calibrate using Avia for your DVD player and then use those same settings for watching cable TV -- or worse fail to even adjust settings for your TV source -- then your TV watching may very well be improperly set. The only thing you can be sure of with Avia is that you have established settings for THAT DVD player, used via THAT input, in that resolution etc. Getting a good calibrated image out of your DVD player will help train your eye so that you can adjust for your other sources where Avia can't be used directly.

Also, when setting white and black levels, keep in mind that they interact. Every time you change one you need to double check you haven't messed up the setting for the other. Plasmas can be quite finicky about proper white and black level settings, so if you have the black level off even a little bit, or even if the white levels are set too gray, the loss of black details can be pretty noticeable. CRT-based displays can be a lot more forgiving in this regard. You want to take the time to be pretty precise when using Avia on a plasma.

Finally, there is an issue called black-crush, or failure to pass "blacker than black" data that arises with some DVD players. This too can give you problems that show up as apparent loss of black detail even though the levels are set properly on your display. You might check the DVD forum to see if that's an issue with your player.

Your Pany plasma has pretty good contrast -- excellent for a plasma -- and so you should be able, with patience, to establish calibrated levels that producing pleasing but not garish bright scenes and rich, detailed dark scenes when viewing high quality source material. Just keep working at it.

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Here's a suggestion. Use one mode (Cinema, for instance) for low light/no light viewing and another mode (like Standard) for daytime/lights on viewing.

Each of these modes have their own presets, but you can change the settings to what you want. Because of this, you can calibrate with a calibration disc (such as Digital Video Essentials or Avia) in the Cinema mode and then change to the Standard mode to calibrate for the change in environment (ie; different lighting conditions).

If you want to be sure your player will pass below black video, you'll have to use Digital Video Essentials (or even the older Video Essentials) as Avia contains no below black signals. At the time it was made, Guy Kuo used an MPEG encoder that clipped the digital signals
This has been discussed before:

With Avia, DVE or whatever, if it's on a DVD, all you're doing is calibrating your TV for your DVD player. Far better to get your essential HT set-up and diagnostic tools from something like my "The Ultimate DVD, Platinum". Give's you training in calibration--test-patterns out the wazoo--plus a "blue-screen" and how to set gray-scales with it--on and on.

Anyway, first get one of those and learn HOW to calibrate. Then, tune in D* on Tues. 7amCST for their test-patterns and then you recognize what you're seeing and you can assure yourself that you are calibrating your TV(!) and not just your DVD player.... Works for me.



Avia has a whole tutorial on how to use the test patterns also... So I think you can learn with it quite easily if you just take the time to listen. And I agree, if you have a broadcast source for test patterns that's the answer, I wish I could get HD test patterns up here...

Luder, if you're concerned about losing detail in the blacks then what you can do is crank the brightness for a bit (hopefully you can pause a dark scene). It will eventually turn all the black to grey and you can see exactly where the last of the detail ends from the source. From there turn the brightness back down to form a compromise between showing detail and having blacks that are not grey.

And also, be sure to give the calibrated settings time so that you can adjust to them. After watching a bad signal for years it can be hard to let go. After about 2 weeks I started to appreciate the new settings and then I could no longer watch the average mis-calibrated set. So I adjusted my bro's set and it took him about 2 weeks to come around too. It really is better to have your TV well-set, just give it time (and make sure that is actually is set properly.) :)
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Be careful about turning up Brightness (black levels) based on when new detail stops appearing. If your source and display are working properly, the video signal, be it component, HDMI or whatever, contains "Blacker than Black" data -- real data that is, however, *NOT* supposed to be visible when viewing at properly calibrated levels. It's there to provide headroom for any signal processing that needs to be done -- such as scaling -- so that you don't get artifacts due to artificially cutting off the data at what is, after all, an arbitrarily chosen value for "Black" set by the source content producers.

For example, video standards for the digital signal sent via HDMI or DVI encode the producer's choice of "Black" as digital 16. The values from 0 to 15 then carry "Blacker than Black". If you turn the Brightness up so far that the Blacker than Black data becomes visible, then you will see more noise in the dark portions of the image since the quality of reproduction of the Blacker than Black data is generally lower all along the path from original recording to your display.

The leftmost moving black bar in the Avia test screen is encoded as one notch above "Black" -- regardless of what signal level your DVD player transmits for the producer's choice of "Black" (i.e., either the darker 0 IRE or the lighter 7.5 IRE) and regardless of whether or not your player and display properly preserve "Blacker than Black" data. Thus by making that left bar in Avia just the slightest bit visible you have properly established the black level on your display independent of whether or not Blacker than Black is being properly preserved by your hardware. Of course if you change the 0 or 7.5 IRE choice on your source device you have to recalibrate.

If dark scenes are still too dark for you, the fix is probably to raise the over-all light output of the display without forcing "Blacker than Black" data to become visible. You would normally do this by raising WHITE levels (Contrast) and then re-adjusting the black level to make only a hint of that left moving bar visible again.

Some displays offer a separate control (e.g., on the Fujitsu plasmas it is named Luminance -- accessible only when using "Fine" picture mode) which also has the effect of raising over-all light level. On displays which make "secret" adjustments in the background when you change picture mode -- rather than just changing the pre-set starting points for Brightness and Contrast -- picking a brighter picture mode will also do this for you. But you should experiment first with simply using a higher white level and re-adjusting black level with Contrast/Brightness before going that route.

If your source device allows you to choose between 0 or 7.5 IRE for the "Black" signal, some folks find they have better luck calibrating for the brighter setting. Often this is due to the fact that either their player or display is clipping out the Blacker than Black data when set to the lower level and they just don't know it. The 0 IRE choice, you see, sometimes also forces PC standards for the signal (weirdly and confusingly called "Enhanced" black in some menus) which do NOT preserve Blacker than Black. Digitally speaking, the PC standard encodes "Black" as digital 0, leaving no room below that to transmit "Blacker than Black".

The loss of Blacker than Black data also presents itself as an apparent loss of dark detail in scenes as the signal processing incorrectly forces more near-black data to be turned into black.

This Blacker than Black stuff can be tricky. Some players and some displays for example improperly clip it when set to 480i resolution even though they work fine when set to 480p. Other clip it only at 480p. Properly engineered video hardware passes it all the time, regardless, as long as you haven't selected PC standards by mistake.

There is no test screen in Avia for determining whether or not your hardware is properly passing Blacker than Black. The DVE calibration DVD DOES show this. Also, some DVD's have a "THX Optimizer" on them -- a set of tests for seeing how your setup is working. Although using the THX Optimizer is by no means ideal for proper calibration -- certainly not a suitable substitute for using Avia or DVE -- it does have one good thing. It has an easy test for seeing whether Blacker than Black is being preserved in your setup.

In the THX Optimizer, select the test screen for checking white and black levels -- it has a big "THX" in the middle of it. *TEMPORARILY* crank up your black levels way too high by cranking up the Brightness control. If Blacker than Black data is being properly preserved by your DVD player and display as currently connected and set up you will now easily see a "drop shadow" behind the "THX" and you will also see additional boxes appear to the right of the gray step boxes along the top of the image. These features are encoded as "Blacker than Black". When you reset your Brightness down to its proper, calibrated level, NONE OF THESE SHOULD BE VISIBLE EVEN A LITTLE BIT -- they should all become just the same as "Black". But the fact that you can see them when you crank up the Brightness (temporarily) proves the Blacker than Black data is really there for the signal processing to use. [NOTE: Avia and DVE are more accurate than the THX Optimizer. If the Optimizer seems to be telling you to change your settings a bit from what Avia or DVE showed you, ignore it and trust Avia or DVE.]

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Originally posted by a. macree
Then, tune in D* on Tues. 7amCST for their test-patterns and then you recognize what you're seeing and you can assure yourself that you are calibrating your TV(!) and not just your DVD player....

Are you referring to the HDNet feed or is there an SD feed as well and if so what channel?

Thanks for the details Bob... I agree with what you're saying. I was just suggesting that as a verfication that his calibration is reasonably close he can always check what detail's there. In the end I wouldn't expect that you could show the "blacker than black" without having the actual black grey which hopefully no one would do...
great tips! especially on the blacker than black. Upon reflection (watching dvds), that is mostly the problem i am seeing.
Bump on Hemi's question to AMC about HD test patterns. What channel is that on? Thanks.
Originally posted by Funnybone
Bump on Hemi's question to AMC about HD test patterns. What channel is that on? Thanks.
ch 79 DirecTV (HD NET)
How about DISH? I don't have DirecTV. Thanks again.
This is content transmitted by HDNET, not by DirecTV. HDNET is currently channel 79 in the HD service of DirecTV. If you have HD service on your DISH or VOOM or cable-TV box, hunt around for the HDNET channel. HDNET transmits this 15 minute set of 3 simple test patterns Tuesday mornings at 8 am Eastern time (adjust as necessary for your time zone). They don't transmit it every week, so you'll need to keep checking. HDDirecTivo box owners (HR10-250) should record a copy of this program and set the recording to never be deleted. It is handy to have around.

If you don't have HD service, I know of no standard-def, national channel that is transmitting useful test patterns.

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