Many users will not have the problems passing the Blacker Than Black and
Peak White data anticipated by these comments, but this approach to
setting up gray scale levels will work whether or not your setup has that
problem.
First of all, try the alternate data formats from the OPPO to your AVR and
from your AVR to your display. Some devices only clip YCbCr or only clip
RGB.
Note
If you use what the OPPO calls RGB PC Level there is no place in
the data format for Blacker than Black (BTB) or Peak White (PW) data
so they will, necessarily, be clipped. Other devices often call this
format something like "Extended RGB" or even "Enhanced RGB" although
there's certainly no reason to prefer it for home theater use. The PS3
calls it "RGB Full" (although the PS3 has a bug that even clips BTB
and PW data when using "RGB Limited").
What the OPPO calls RGB Video Level and others usually call "Studio
RGB" will pass BTB and PW data to properly engineered and set up
receivers and displays. For some background on what's going on in these
data formats and some hints as to why you might prefer one over the other
when paired with particular hardware, see What if I want to set the color
space manually?
Again, it is worth trying to find a way to set up your hardware to pass BTB
and PW data, but with some AVRs and displays you just won't be able to do it.
In that case you can still use the Spears & Munsil disc to calibrate
your video levels.
I'm going to assume you are directly connected to a display. If connected
through an AVR, you have an additional point of adjustment.
The first suggestion is that you leave the OPPO's Picture Adjustment
settings at their factory default values. Try calibrating using only the
controls in your Display. If that doesn't provide a complete solution,
next look for level adjustment settings in your AVR. If that also doesn't
provide a complete solution, or if you are having problems coming up with
display/AVR settings that work for all your source devices (and your
display/AVR don't provide separate memory settings for use with different
devices), then, finally, use the controls in the OPPO.
The reason for this is that the OPPO puts out "correct" levels at its default
settings. So if you find things are not right using those default settings
then that's an indication there is something wrong in the settings in your
display and/or AVR.
One more preliminary
The factory default settings in most displays are flat out wrong
for best quality viewing. These are the justifiably disparaged "torch
mode" settings -- way too bright and contrasty, overly sharpness
"enhanced", way too blue a color temperature, and overly red pushed to
compensate for the faulty color temperature. The "torch mode" settings
are designed to be eye catching in garish store lighting. So do not
hesitate to move away, often far away, from the factory default
settings.
Everybody has to do that.
Many modern displays offer "picture modes" that are different combos
of factory default settings. Avoid like the plague any modes labeled
"vibrant", "dynamic", "scorch your eyballs" or the like. Try to find
one labeled "movies".
If you can't figure out which to use, pick the one that looks darkest
and softest and start from there. And don't assume you can pick just
any "picture mode" and alter it via user settings to be
correct. "Picture modes" often make hidden setting changes in the
background that you can not alter from the user controls. So find the
correct "picture mode" to begin with and make your adjustments from
there.
So again, assuming you are directly connected to a display:
- You will use the Brightness control in the display to adjust Black
levels (a good way to remember this is that they both start with "B").
- You will use the Contrast (or Picture) control to control White
levels.
The two controls interact so you will need to iterate to find the sweet
spot setting for both of them that works best.
The next thing you need to know is that the data coming off an SD-DVD or
Blu-ray disc encodes "Black" as digital 16 and "Reference White" as digital
235. The range from 1 to 15 is the Blacker than Black data (not intended to be
seen) and the range from 236 to 254 is the Peak White data (intended to be
seen but not essential). 0 and 255 are reserved values.
The Spears & Munsil charts actually label blocks that have been encoded with
values above and below Black and Reference White.
- Use the Dynamic Range Low chart for a best look at Black levels.
- Use the Dynamic Range High chart for a best look at White levels.
- Use the Contrast chart to view both at the same time in an image
that's got a kind of "in between" average image brightness.
So what you do is lower the Brightness control until 17 and above become
invisible (blend into the black background) and then raise it until 18
becomes slightly visible (and perhaps just the slightest hint of parts of
17 are also visible -- i.e., a few "dither pixels" light up). Note that
you should not see 16 = Black or below. All of that data should merge
into one, uniform, indistinguishable "Black". Also note that you will need
to check this sort of thing in a darkened room.
Note
Some displays have "floating" black levels that vary according to the
average brightness on screen. So if you look at say the Pluge Low
and Pluge High charts you may see a distinct change in your
effective black levels. Some such displays have dynamic brightness or
automatic brightness settings that can be turned off to prevent
this. If not, you will need to pick a compromise Brightness setting
that works well across a range of content for you. Typically you would
target a lower Brightness setting that works well in dark scenes so
that you don't see noise in dark scenes -- at the expense of losing
some "near black" details in brighter scenes.
At the other end, lower Contrast quite a bit. The bright blocks in the
Dynamic Range High chart should be visible although you won't see any
above 234 due to the clipping in your display or AVR. Now raise Contrast
until whites have a pleasing "whiteness" to them rather than looking
grayish, but don't raise it so far that you lose the ability to
distinguish the blocks at and below 234. If those blocks at and below 234
start to blend into one common "white", lower Contrast until they become
visible again.
Note
If your display and AVR don't clip the BTB and PW data you still
want to adjust Black levels so that 16 and below are completely
invisible. At the other end, see if you can find a Contrast setting
that is high enough to give a pleasing "whiteness" to whites but also
low enough so that you can distinguish the Peak White blocks all the
way up to 252 or even 253. The "correct" Contrast setting will almost
certainly be quite a bit lower than its factory default setting.
You may find that you have a small set of Brightness/Contrast pairs that
look equally good. If so, you can choose between those pairs by viewing
the gray scale ramp on the Contrast chart. Pick the pair that produces
the smoothest look to the ramp -- the least amount of "banding".
Brightness and Contrast control the end points of the gray scale ramp. The
response of the display to values between Black and Reference White is
controlled by the Gamma setting. Many modern displays have Gamma set too low
by factory default as this gives "false pop" to the imaging in stores. Just
another "torch mode" setting.
Adjusting Gamma is complicated. Doing it right requires an optical sensor
tool. Nobody has much luck trying to do full Gamma curve adjustments by eye
alone -- although some displays offer a single, all in one Gamma adjustment
that may prove helpful. So I'll only point out here that if you do adjust
Gamma you will probably find that Gamma, Brightness, and Contrast all
interact. So you will need to iterate -- re-checking Brightness and Contrast
as you adjust Gamma. (Proper Gamma correction is a major factor in eliminating
"banding" or "false contours" in your video. So it is worth the effort to get
right. But as I said, this is complicated).
There's a whole Calibration Forum here. Check out the sticky threads in
that forum for additional suggestions.