Originally Posted by hariskar
I am confused...
My player Pioneer DV-600 has an option to show BTB and WTW.
How should I configure it? The readme of the firmware that allows this option says: Enable BTB, put the players Brightness to +1 and Contrast to -1. So it gives BTB and WTW info.
If I do this I can see BTB and WTW bars from GetGray DVD. Should I calibrate my tv to see or not to see BTB?
Sounds like a load of BS to me. In digital video, "black" has value 16 (for luma in component video). So, on a DVD where there is "black" the digital value 16 appears. If the DVD player works correctly, the value 16 will be output on the HDMI cable to the display. If you increase brightness +1 in the player, it will take the value 16 and add 1 (or 2, or 3, or more depending on how the brightness control is "tuned"). So, now the 16 (black) is no longer output as 16, but as 17, or 18 or some other number higher. Your (properly calibrated) display sees it and it does not output black, but something lighter.
Ok, so now if you have BTB on a disc, eg. 15 or 14 or lower, the "player brightness at +1" will cause the value on the disc to be output at 16 or 17 or something. BTB is not being output, but some brighter shade of black/gray. Changing brightness (or contrast, or any other color/tint) on the player modifies the digital video values coming from the disc. That's not why you buy a DVD player, you buy it to output what is on the disc.
The way to tell is BTB is being output by the player is to properly calibrate your display so that "black" (16) is "black" (no light) on your display. Once you do that, anything at 16 or below will show as "black". If you want to see if BTB is passed by the player, view a test pattern with BTB information. Then raise the brightness on the *display* and the BTB information should be seen after raising brightness a tick or two or three. If you don't see the BTB bar or whatever, the the player is probably not sending BTB data. Raising the brightness on the display takes the BTB (eg 15) and adds adds 2 or more to it so that it is 17 or 18 allows them to be seen. In fact, you should be able to lower brightness on the *player* and still be able to see BTB video on the display by raising brightness. It's all just math. Subract some on the player end and if you add enough on the display end it will be visible. Most players don't modify the video when controls are in the "neutral" position, but lowering the brightness on the player will guarantee it is passing BTB video if you can see it on the display after raising brightness. If the player is not configured properly at the factory, it could possibly add (or subract) something to the video data value. That's why we have the nifty calibration discs.
BTB video should not be seen on a digital display when properly calibrated. "black" should be set to "panel off/no light" so it's kinda hard to display something darker.
BTB is necessary for scaling and to help maintain proper black levels for CRT displays if the BTB data is on the disc.
Most digital displays can output WTW when calibrated correctly. And if the player can output BTB then it is most likely outputting WTW too. If no BTB is output, then WTW is probably clipped also.