AVS HD 709 - Blu-ray & MP4 Calibration - Page 9

Google shows your TV is a LCD RPTV, so it's probably a digital TV and the clipping pattern might apply. If you turn down contrast (maybe picture being a Sony) and still can't see flashing bars on either the second or thrid pattern, then I'd guess something would be clipping the top-end of the grayscale. Some digital TVs have controls that can clip the top-end of the grayscale, and some sources might clip the top-end of the grayscale. I've never seen your TV and you don't list the source so I really can't make much of a guess why you wouldn't be seeing the bars. With typical settings neither my TV or sources clip the grayscale, and only my computer expands levels and clips by default.

The circles go to the edge of the 1080p image, so if you have an RPTV that overscans then the circles will not be on-screen. The bottom and right lines of the grid are cut-off on the W6RZ original. The pattern is included for basic geometry and convergence, so the very bottom few pixels of the lower circles being cut-off isn't really a concern. An LCD or Plasma are the only TV technologies that might show the pattern without any scaling, and convergence and geometry are not a concern with those TVs.

EDIT: I looked at the DVE HD pattern and it is different. The circles on that pattern seems to be contained within about 2.5% overscan.

He was talking about white-levels. With the digital TVs I've owned, black level controls haven't had much effect on white-levels. Again though, I'm not familiar with how his TV might work.

Based on what? Clearly I would suggest to see if DVE or Avia come back incorrect with the setting that this disk gives. I think that both of those disks might use 2% levels near black. That would mean you could probably go lower on brightness before you start seeing clipping on their bars, but doing that you could still be clipping grays. GetGray I think uses 1% which is a little closer to black, but I found the movement harder to pick out than the flashing. Anyway, on my players all of the disks are in agreement.

A model number search says the TV is an LCD. Of course the source or other settings on the TV can also alter levels. To this point, no one has indicated that the pattern or description of how to use it would be incorrect for digital TVs.

By your description it sounds like you're cutting out a lot of detail in the low-grayscale. If the TV has a backlight control, you might try turning it down with the brightness the disk is showing. That might darken up the black without so much clipping. If the second (APL) pattern is showing the same setting as the first black clipping pattern, I can't come up with a reason to set the black-level much lower. I know I could hardly stand the LCD I had because of poor black levels.

I could be wrong, but I figure it clips based on the brightness setting like most any other digital TV.

I don't remember, what are the issues with the Toshibas over DVI? This sort of thing can be difficult to troubleshoot third-person, but I'd probably see what happens using component. That's the first thing that comes to mind, so I'd start there.

For the Sony SXRDs there have been reports that the sub-contrast in the service menu can affect clipping, but that's not exactly the behavior I saw on the A2000. I suppose it's possible the Sony might have user menu controls that would clip, but the SXRDs don't have anything like that. Based on the 3 Toshiba HD DVD players I've used, I can't really expect the A3 would have controls that would clip. Basically the long-standing problem reported about the Toshibas and DVI is the only thing that really comes to mind, but I've only used HDMI so I don't know what that problem was about.

Thanks for the offer.

I take it with 2.35 you're talking aspect ratios for front projectors. I'm not sure if commercial disks are encoded at 1080p with black or if they're at a different resolution. By what I've seen in documentation I would guess they're 1080p and in that case it probably wouldn't be a big deal to include. Looking at the Wiki, I'm not even sure what the height you would be talking with the mention of both 2.35 and 2.39 ratios. If you want to submit some sort of image that would prove useful for your application we'll consider it.

I've just been trying to keep the original post up to date. I'm not very good at reading through threads that I don't look at regularly, so I don't necessarily intend anything past the first couple posts to be too important. Most of the development items have been done outside of the forum. There for a bit there was some talk, but generally there have been few comments regarding the known issues section. I figure if we run into anything serious it will show up in the known issues. Aside from the 24p item, most of that section hasn't much changed since the first disk was released.

Thanks for the idea about the sharpness pattern. I think for now we'll probably release a pattern based on the Imatest image on the next disk and see what people have to say about that. I seem to get very similar settings using it as I do with DVE HD or the Sony Blu-ray pattern. The more I looked at the images geared more toward cameras I found that they tend to show a lot of scaling issues at 1080p. For example I'm almost sure the Sony Stars have a number of effects of scaling in the original image from the 12233 pattern and some of the slanted lines are a complete mess if I remember correctly.

On SXRD I expect you would find that windows or fields hardly differ. The 100% window might have a slightly higher Y, but it's probably not exactly going to show up much in gamma. Looking at http://www.avsforum.com/avs-vb/showthread.php?t=958099 it seems that your measuring device might have a bigger effect on the measured result than the choice of window or field based on what I've seen from SXRD measurements. The impression I've got is that windows might be slightly closer to the requirements of most program material and present fewer problems for certain display devices, so generally that's why the disk is centered around using windows.