AVS HD 709 - Blu-ray & MP4 Calibration - Page 69

The bars disappear as the display runs out of available contrast. Generally at a low contrast setting you should see all the bars. I would suggest to get the maximum contrast and brightest whites out of the display you will want to try to use a high contrast setting.

In Total Media Theater 3 I'm getting matching gray levels regardless if I play the patched disk or a file. I'm using an old ATI HD 2600XT card with current drivers on Windows 7 x64. There was a possibly similar report with the same program, but a different ATI video card at http://www.avsforum.com/avs-vb/showt...1#post18218821 There are a lot of things that you can do with software on a computer, and I know it took a while for some driver issues to be sorted out for my card. According to http://www.upsilonsoftware.com/blog/...nt-levels.html the software uses a different renderer between the two modes. I probably can't give any better overview depending on the video adapter than the last link.

I do not have the stated issue. http://www.upsilonsoftware.com/blog/...nt-levels.html lists the program as using a different renderer depending on the mode selected. Without any further information I have to assume that the video chain is reacting differently depending on the renderer. Basically my best guess is that what you're seeing is probably related to the graphic card you're using. A thread on your graphic card or the prior link is the best guess I have to start troubleshooting what your computer is doing. The only other thought that comes to mind is to try another calibration disc and see how the disc mode reacts http://www.avsforum.com/avs-vb/showthread.php?t=852536 includes a free DVD that should have basic grayscale settings patterns, but unless Digital Video Essentials HD Basics happens to react differently I cannot expect that the issue is with the disc at this time.

Looking at the online specifications for the WDTV Live it appears that it will play MP4.

The easiest way to find out what is going on with the decoding is to measure colors. There is a pattern in Digital Video Essentials that is meant to be looked at by eye that has both the 601 and 709 colors, and the description there goes over what you may be able to notice depending on decoding. Personally I find the DVE description hard to understand on its own, so I recommend measurements if you really want first hand info on what's going on with colors on your display.

Somewhere in the video chain the YCrCb from the disc will be decoded to RGB. How the conversion takes place will depend on the device doing the decoding. By default most Blu-ray players will probably pass the info from the disc without converting to RGB. There are devices that can decode and pass RGB, but typically most standalone players will output YCrCb. Again there are probably receivers that can also decode, but by default a receiver would be expected to pass the video without conversion. So if commonly the player and receiver are not used for decoding, then the conversion happens at the display. My TV is a Sony and it decodes the colors depending on how it is set. By default my TV will decode depending on the resolution, so a HD input is decoded with Rec 709. In short how the conversion is handled will depend on where the conversion is taking place and how that device is doing the conversion, but in the quoted example the TV is most likely doing the conversion.

I decided to look further into how Digital Video Essentials would measure with a slightly different gamma when compared to measurements from v1.3 of AVS HD 709 (current known issue #1). It appears that DVE uses Y values 1 lower from 5% to 50% compared to what is currently on AVS HD 709. The AVS values are generally closer to the stated percentage, but the DVE values place the unusual step near black in a 5% or 10% series.

NOTE: 235-16=219, and 219 is not an even number so it doesn't allow for an even number of steps from black to white.

 

Comparison.zip 2.474609375k . file

I am not familiar with the player or display to comment if it's possible to show 1-15. You don't have to be able to show 1-15, it's just easier to see what's going on if you can display 1-15. Since you're not able to see 1-15, I would suggest using the APL pattern and setting brightness no lower than where you can see somewhere around 20 and up flash.

Aside from things like copyrights, part of the reason why test patterns and descriptions aren't entirely uniform is that TVs vary to some extent. Generally though there is some amount of agreement for setting brightness, contrast, color, and sharpness controls. I know that I found patterns frustrating the first time I looked at DVE and Avia, so asking questions on how to make adjustments or stating specific issues is welcome.