Go-to Guide for Source Options - Page 3

sunra
What gamma setting are you using? The NEC should be set to a 2.2 gamma. If that doesn't fix the loss-of-detail problem (when using the PLUGE pattern in Title 12 Chapter 2 to set black level), try using the Reverse Gray Ramps in Title 12 Chapter 14. The blackest bar is below black -- not sure about the digital level, probably around 12 -- so raise the Brightness control until the black bar next to it (which is at digital level 16) can just be distinguished from the below black bar, then back off 1 click. Black (digital level 16) has 3 white dots above it on the left side of the screen and below it on the right side of the screen.

I was actually considering a 50" NEC last February. Very impressive features and a shitload of adjustment capabilities. Unfortunately for NEC, their black is dark gray. In Plasmaland, Matsushita owns black -- now and for the foreseeable future. That's why I went with the 50" Panasonic 6UY instead.

Chris, et.al:

Hopefully this question isn't to elementary and close enough to on-topic.

In studying the thread, I believe I have a handle on the issue. I'm a little fuzzy on the white level setting. I know this isn't a calibration how-to thread but to help me understand, please allow this tangent. WHen adjusting my (DLP FP) contrast I have used the Avia pattern with the moving white bars. Since this is the consumer Avia, I believe I read that it's white 100IRE pattern levels are at reference white. I've adjusted my DLP so as to make only one of the 2 moving bars on that pattern visible. I have DVE, let me know if there is a more appropriate/better pattern and method there to adjust with.

Back to the real question... On my PJ there is a setting called "White Peaking" Since this is a term that's been used (sort of) in preceding posts, I thought it might be related to this discussion. In the case of a DLP display, can you or anyone enlighten me on what this setting actually does, as it relates to the input? What would be the proper way to adjust said "White Peaking" or account for it in the input?

Or is this parameter not relavant to the input and just a PJ behavior enhancement feature?

Thank you very much for the help and the great info in this thread.
Scott

As to the White Peaking "feature", what are the available settings: on/off, variable, etc? It does sound like a limiter of sorts and, as with most "features" (check out SVM in the asinine Mitsubishi "feature" lists in the Best Buy ads), it probably does more harm than good.

For white level on DVE, you can use Title 12 Chapter 14 (Reverse Gray Ramps). There are 3 black dots marking white and the outer white bars are just above white. Set the Contrast so the the white bar is just distinguishable from the outer above white bar. You can also use the pattern in Title 13 Chapter 2, the SMTE RP 133 pattern. There's a white box (100% white) that has an interior white box which is lower in intensity (95% white). [Note: the actual white box to use is actually to the left of the solid 100% white box] Set the Contrast until both are equal, then back off until the lower level box is distinguishable from the exterior white box. Joe Kane recommends either of these two patterns for digital displays, but, depending on your display, one of these patterns will probably be easier to use.

Thanks Joe. It's a 1 through 10 setting. The manual is kind of ambigious as to what it does. It says" Use the white peaking control to set the white peaking level (DUH) of the DMD chip. "0" stands for minimal white peaking, 10 is for maximum." But then it goes on to say: "If you prefer a stonger image, adjust toward max, if you prefer a smother more natural image, adjust toward min."

And thanks for the contrast adjusting methods. I think I lost you on the boxes but with the pattern up I'm sure it will become clear(er).

Thanks,
Scott

Joe Murphy Jr:

Gamma settings range from 1-4 on my NEC, I am using the default setting of 2.

Bob P.:

With the default NEC brightness setting I am actually very happy with the black level and resolution of detail with almost black images , very little black crush. Of course just because the default looks good didn't stop me from trying to make it better, that's when I used DVE to adjust brightness to where the 3rd black bar just disappears ( this requires substantial reduction from the default setting). Calibrated in this way, when I watch "Matrix" or "Planet of the Apes" there is significant crushing of black or near-black detail. When I go back to the default setting it looks fine. More than anything I trying to understand why what should be properly calibrated black level looks so bad. I will have ISF calibration done in the next few weeks, hopefully that will shed some light on my darkness question.

>>>Gamma settings range from 1-4 on my NEC, I am using the default setting of 2.<<<<br />
sunra
I believe the 1 - 4 could be replaced by A - D. Setting 2 (aka "B") should correspond to a gamma of [insert a real number such as 2.0, 2.2, 2.5 (2.5 is probably the max)]. The manual may give you the actual numbers.

Make sure you have at least 100 hours (preferably 150 - 200) on the NEC before spending the money on an ISF calibration. I would hope that the calibrator made this clear when you set up the appointment.


scott
Yes, it will become more clear.

Very interesting read Chris,
But this leads me to an obvious question. If we know that NTSC OTA is all over the map and that there needs to be a correct calibration done for DVD playback, why would MCE2005 have you do your brightness and contrast calibration ONLY on the display device?? I'm sure there are ways abound this but MCE would lead you to believe that these are the absolute reference calibrations using there very well mastered reference material as the source.
As we all know this just doesn't exist and there needs to me adjustment done within the DVD player and the tuner to actually get these levels right. Otherwise one or all will suffer.
All of the Software DVD players out there have this ability and in some like TT you can setup individual DVD's to remember their individual setting.
But in MCE2005 I don't see the brightness, contrast, saturation and hue setting in the player (unless I missed them??)
I didn't read all of this thread so if something has been written on this, my apologies.

Terry

Maybe this will help anyone trying to set up DVD software on a HTPC...

My HTPC has an nVidia 5200 Ultra (66.93 driver), outputting over DVI to a Samsung 43" DLP. I use Zoom Player Pro + ffdshow (10-12 version), with DSclaer 5 audio/video codecs.

I had been using Overlay for my video renderer for a long time, because with the way my DLP is calibrated, the VMR settings looked out of whack (and used a lot more CPU power). I used the Phillips Pattern Generator and www.displaycalibration.com to match my DLP's settings to my HTPC. Doing so meant that my Overlay settings were perfect, and I didn't need to use any adjustments in my playback software or ffdshow filters. (I also changed my HNL DLP's gamma setting to 0, which is the best one and greatly improved PQ, especially SD cable, no more "clay faces")

However, after finally understanding a lot of other things in the HTPC/DVD-software realm, last week I finally got to this thread and discovered the "truth" behind levels. I was finally able to understand it, after having spent time using Levels in ffdshow to compensate for darks/lights, then actually using my display's Service Menu to calibrate it properly.

So, using Overlay, I tried to see if I could see the BTB section of the THX dropshadow screen (Monsters. Inc.). It wasn't there.

So I tried switching to VMR9, and it suddenly appeared. So I adjusted my Brightness (black level) to where it was before. But this was still too bright (blacks were grey). So I dropped Brightness from 50 (out of 100) to 40~41, and I got the blacks/levels perfect.

By switching to VMR9, I was able to get my BTB back. I checked a number of scenes in Finding Nemo, Matrix Reloaded, and more, and noticed that the picture seemed noticeably (yet subtly) better. What stood out the most was an almost complete reduction in banding (water in Finding Nemo, skin tones in Matrix (rave and Neo+Trinity chapter)), and also better shadow detail in certain scenes (ie., detail/buttons in Neo's jacket in Chapter 3 of Matrix Reloaded, when he is handed Smith's earpiece by the guards).

So, although VMR9 uses a lot more CPU power and I have to resize at 1280x720 rather than 2000x1600, my picture overall is much better. All I have is some Luma Sharpening within the Lanscoz 4 resize anyway. Supposedly there is a renderless VMR9 mode in the works for Zoom Player, so that should speed up VMR9 a whole lot.


I know Overlay vs VMR9 issues may depend on video cards and drivers, but if you're trying to tweak your HTPC, definitely check if you have BTB or not. If not, try switching renderers and get that correct. You'll definitely improve the PQ.

the problem is that with an htpc we gan adjust contrast,brightness and gamme in the player and thus compress the image dynamic, so how to calibrate the computer and the display at the same time ?
is a scope the only way to calibrate the analog outputs of a htpc ?
What about the digital outputs ?

Chris:

I think I understand the BTB thing, and hitherto have calibrated my HTPC/DLP PJ using DVE. Feed is DVI from Nvidia 6800GT card. I use ffdshow as the final post-processor. In ffdshow you can map the input digital levels to the output and there is the option to map the range 16 -235 to 1-254. i have tried doing this because at some point in the past there was a post recommending it. At the moment I am not doing it. Am I right to pass thru the full range including BTB and 'above white'?

The PJ (Sim2 HT300+) has Video and PC settings. I use the video setting so I tell myself I am seeing Studio levels.


Andrew

seyfang
Use the 16-235 output on the HTPC and the Video settings on the projector for Studio RGB.

I thought that if you did this in ffdshow you were compressing BTB and WTW into the 16-235 range?

Correct me if I am wrong, but you want to output full range, i.e. 0-254, but make sure that everything is calibrated for black = 16 and reference white = 235.

I'm not familiar with the program, so I wasn't commenting on how to utilize the settings.

The point that I was making was that the output from the HTPC should correspond to 16-235 for the video signal, thus placing black at 16 and white at 235. Below black and above white would be output as 1-15 and 236-254, which are the correct levels for video.

Agreed.

I just wanted to highlight that depending on how you use the levels filter in ffdshow you can either clip or compress ranges.

If you've been pacing the halls regarding purchase of Avia Pro, onecall.com wants you to stop. They're running a special right now ($100 off retail) on this multi-disc calibration set, but it won't last long.

Been there, bought that! Thanks for the pointer.
--Bob

Bob
I thought Guy had already given you a complimentary copy of Avia Pro?

Nope, no tchotskas here.

By the by, I just spoke to Ovation, and they expect the audio test discs for Avia Pro to go into Beta testing any day now and hope to be able to start shipping them out to Avia Pro owners around the beginning of March. That would add the final two discs to the set as originally conceived -- Audio and DVD-Audio tests.
--Bob

Quote from first post:
"To reiterate, all the previous statements were nonsensical and meaningless. They represent confusion on the facts surrounding analog voltage outputs(expressed in mV or IRE units) as opposed to what is digitally encoded on the DVD."

If I'm designing a video A/D converter (which are used everywhere today) to sample a standard 0.714v (or 1v p-p with sync included) analog signal with a standard 75 ohm termination, what are the correct digital values to assign using limited digital black and white?

Is 0.000v assigned a digital value of 0?
Is 0.714 volts assigned a digital value of 235?

To deny that there is no relationship or simple linear conversion algorithm only serves to confuse the matter.

For non-computer based displays:
How does one calibrate common fixed pixel display "properly?
Does one calibrate for maximum output for an input value of 235?
Or does one calibrate for maximum output for a value of 255?
What do the service manuals state?

Does a fixed panel source light bulb generates the same amount of light?
Or are the "BEST" display manufactures modulating it with the input signal?

Well it is rare indeed on AVS forum when someone earns my respect. And you just did Chris:
"The white point is somewhat user subjective, but you would want to include some peak white detail within your calibration range in my opinion. "

A huge problem with with the Internet and especially AVS forum is that their a many self proclaimed "experts" who state their opinion as fact. Or even more importantly, attempt to add to or change an existing international standard because, in their opinion it is wrong. Such arrogance, especially when their solutions are unable to withstand even elementary scrutiny.

You, in your reply, realize that their is an important compromise involved in SELECTING THE ONE WHITE VALUE where the projector generates its maximum light output to the screen.

The dilemma is if the projector is calibrated to white of 255, then the average light output will decrease substantially.

If you calibrate to 235 then these over spec values are clipped and simply displayed as white.

So the choice is either greater average light output OR reproducing an occasional peak with greater fidelity. Since most projectors are too dim, I would expect most people to choose greater average light output. The fact is there should only be one value defined for white, just as their is for black. That is, in my opinion. Have a nice day!

From page 13 of the Avia Pro Guide.


Dave

I can't say what his assumptions were, but based on what I've observed, measured, captured and documented, I'd agree with the assumption about the assumption. He goes on to say this about the usefulness of BTB/WTW



Not sure if you're referring to Guys or Stacys display? but Stacy did state that he had to sacrifice over 33% of his CR for it.

Dave

Stacey is using the Samsung 700A DLP projector that was designed with input from Joe Kane.

Excuse the ignorance here guys, I've been going through this thread and still have a hard time understanding everything. Are we saying that we need to change the input output levels in ffdshow to correct pc levels? Input at 16 and output at 235 in VMR9?

VC