"High Definition Benchmark" BD Edition by Stacey Spears and Don Munsil - Page 17

I will take a look at UP this weekend. Video black should be at 16 at all times.

If there is an issue, I can send them mail.

I just took a look at the test pattern on UP.

1. The gamma pattern does not work. There is a fundamental problem with that style of gamma pattern. I ran into it a few years ago when building a similar pattern.

2. To use the brightness pattern, you have to put your nose to the screen. While it can be used, it is difficult to set correctly. It is easy to set brightness high with this pattern. It looks like the far left bar, on the side you are supposed to see, is at 17. They go up from there as you move to the right. On my display, their pattern, when set correctly, matches our disc.

3. Their contrast pattern should be avoided.

I sent mail to a friend who has a direct link to the powers that be.

WHY!? Why include such a disaster on the disc when it is so wrong?
With all do respect, what's your friend going to do, have them recall all the discs?
Everyone trying to use those patterns will now be dummer for having done so, and more importantly their displays will be f'd up because of it.
This, from a company like Disney, is just ridiculous.

I believe these are the same patterns that have used on previous BD titles. So, they have been around awhile.

I know that John, Andrew and Lee's home theaters don't clip headroom.

o

I recently bought the Oppo BDP-83. It's great that the Spears & Munsil disc comes with it. This is the first calibration disc that I've felt comfortable using with a plasma. I've got a Panny 65PZ850U.

1. With the brightness set at high I can see the left two bars and the checkerboard pattern. I then turned the brightness down so that the left two bars disappeared. The faintest right bar is still visible. However, the checkerboard pattern is also barely visible. Is it best to keep lowering the brightness until the checkerboard totally disappears or is lowering the brightness until the two left bars disappear enough? If I continue to lower the brightness, the checkerboard disappears and the dimmest right bar is still very barely visible.

2. In the Contrast pattern, the #19 bar is barely visible. I can't see the #18 bar at all. At the bottom of the Contrast screen, I can barely see the the #247 box. I can't make the #18 box appear no matter how much I play with the basic Picture/Brightness controls. Is that acceptable?

3. When I go to the the Dynamic Range High and Low screens, the patterns continuously flash on and off. What does this mean?

Thanks, I appreciate the thread.

Just to clarify, do you mean using the PLUGE High pattern?

When set correctly, on the Low pattern, the left two bars should be invisible and the right two visible. The checker should also be visible. From your seating position, the checker should be really difficult to see if gamma is correct.

If your display is DLP or Plasma, you may see something where the left bars are because of dither.

2. The high APL of the contrast pattern makes it difficult to see the black bars on the top. This pattern should not be used to set brightness. The level of bar you see, on black, will depend on several factors, including gamma. I think it 19 or 20 is the minimum you see with a proper gamma. I need to double check at home.

3. The flashing was added to make it easier to see the bars. The 253 bar is difficuilt enough to see flashing, much more difficult when static.

Hope this helps.

Thanks for the reply. I have a Plasma.

1. No, I mean with the PLUGE Low Pattern. I thought you were supposed to turn up the brightness until you can see all four bars and the checkerboards. I though you were then supposed to turn the brightness down until the left two bars disappeared. That's what I did, but I wasn't sure if I should keep lowering the the brightness until the checkerboard disappeared.

With the PLUGE High pattern, I can see the 2 right bars. The lightest bar on the right is barely visible. The checkerboard is not visible at all on the PLUGE High pattern.

2. I'm using the Contrast pattern to adjust contrast using the "Picture" control on the Panny. I did try to use the brightness control in conjunction with the Picture control to see if I could get a better result with the top row of bars. I was trying to get lower numbers around 240 on the bottom and 18 on the top.

I went into the pro-setting on the Panny and set the Gamma adjust to Full1. The adjustments allow for "Normal/MID/Full1/Full2". Full1 made the top bars brighter and now I can barely see bar #18. I can still see up to bar 245 on the bottom row. The MID gamma setting looks better to my eye with real material, but the Contrast test pattern suggest otherwise. I guess I need to get accustomed to FULL1.

3. The highest bar I can see on Dynamic Range High is 247. After that it's all white. The highest bar I can see on Dynamic Range Low is 17 (just barely). The Low is good but the High is not?

Thanks again. You have a great product.

Stacey, some encoders only accept 10-bit or 8-bit 4:2:2 input. When your source is at or greater than 10-bit and sampled at 4:4:4, what pre-processing do you recommend? Do you dither to those formats or merely round? The encoders, meanwhile, will dither down to 8-bit 4:2:0. How do you avoid unnecessary conversions?

Also, I've found you a little goodie. I'm sure you can guess what it is. Send me a PM and I'll link you up.

I tend to only use encoders that accept 8-bit 4:2:0 input when possible. This way *I* control it all. I am a control freak.

I tend to try dither and round from any bitdepth. Its just time. I am not sure I could handle a job where I was supposed to encode for a living. I would never ship anything because it could always be improved.


No, stop as soon as the left two bars go away while still keeping the right two visible. The checker is at 16 and 17, so just barely above black with the 17.

If you are going to adjust gamma, use the image cropping pattern. Choose the gamma that makes the center checker the closest to invisible.


If you turn contrast down, the other bars do not show up? I know that on some Panasonic plasmas, there is a menu with an option called "Input" that fixes this problem. You may have to turn it down to -1 or -2. Its been a while.

Are encoders affected by a source that is chroma subsampled versus one that is not? Will you have improved motion estimation and thus better compression efficiency with the latter?

Hello,
I recently purchased a Panasonic 50V10 display, a Sony BDP-S760 Blu-ray player (both purchased locally) and a copy of your disc from AV Science. My question concerns calibrating the television for viewing both SD and HD content as well as calibrating the television to view BD.
I have an HDMI cable coming from the cable box going to the HDMI 1 input on the tv. Should I connect the HDMI cable from the cable box to the pre/pro that I'm using for HDMI switching (Rotel RSP-1570 pre/pro) instead?
My goal here is to have the best possible picture that I can get on both SD and HD as well as Blu-ray discs. Any help with this would be appreciated.
Thanks.
Rick

While I can't say what all encoders are doing, I am pretty sure most convert to 4:2:0 as the first step. Several encoders do a poor job of converting to 4:2:0. Cinemacraft was applying progressive downsample to interlaced content last time I looked at it.

When you use the disc, you are calibrating for that specific source. With HDMI, it should be easier to match sources. e.g. If you wanted to use the disc, in your BD player, and apply the same settings to a cable box, you would need to ensure you are sending out the same resolution and color space. Even then, its not 100% because you don't know if the cable box is sending out the same color space correctly. On top of that, TV stations levels appear to be all over the map. SyFy was terrible at this. Their black level is elevated compared to other stations.


I would try sending your BD player straight into the TV and through your Rotel and compare the two looking at several test patterns. This will let you know how one path compares to another. I assume your BD player must pass through for audio.

Stacey, thanks very much for your reply. I'll follow your suggestions and see how the patterns look.
Best regards,
Rick

Wow, that's crazy. Thank you for looking into it. Does this mean that the entire movie could have been mastered incorrectly, or do you think the problem is confined to the test patterns?

I suspect the movie is fine.

I've been wondering if there is a particular test pattern that may be useful in setting Backlight level, as opposed to brightness. Surprisingly, switching backlight between 0 and 10 on my display doesn't seem to impact the pluge patterns, so how would I find the ideal backlight level? My display (sony xbr4) also has two power save modes which complicates things further. I usually keep BL at zero (with power save off) but am wondering if it may be too dim (or too bright since no powersave). Does backlight level boil down to just personal preference?

Backlight shouldn't really affect your black level setting. It really just determines the overall light output of the display, so whatever is sufficiently bright for you in your particular viewing environment, according to your preferences.

I assume you don't have the equipment to measure greyscale, but sometimes particularly extreme (high or low) backlight settings can alter the greyscale a bit, and it is simply something to be aware of if calibrating your display.

Interesting. I would have thought that backlight could affect gamma somehow. I don't have anything to measure grayscale, but just out of curiosity, are there specific tendencies for the effect on grayscale? For instance, if backlight is too low, will grayscale be too red or too blue? or vice versa?

Just wondering, is there a specific range of light output, in footlamberts, that is considered ideal?

The backlight shouldn't really have any effect on gamma at all. It is just making everything brighter or darker, and assuming there is no dynamic backlighting going on, then that keeps everything exactly the same with regards to gamma. If you've got a dynamically backlit (say with LEDs) LCD display, then all bets are off, and yes gamma will certainly be involved, among many other things. I am assuming just a fixed non-dynamic backlight.

the footlamberts you want IMO really depends on the viewing environment and what you're watching. For people in really bright rooms who want to watch sports all the time I might turn it up pretty high, and the footlamberts may be 50-70 or even higher depending on the display. For more reference movie watching in a dark room, I would be much lower, say 20-30fL. Also depends partially on hoe big the screen is. People tend to remain satisfied with lower fL on a larger screen than on a smaller screen, in my experience anyway.

I haven't really kept track of extreme backlight settings so I can't make any generalizations about that. It's just something to be aware of, and set backlight close to where you want it rather early on so the display remains stable as you're calibrating it.

Which RGB dynamic range setting would you recommend, Limited or Full? I might be mistaken, but I think I could see every step in the ramp test on limited, so what exactly is the difference that Full would make? Is it the sort of thing where you should definitely use Full if you have it, or is it more complicated than that?

One possible suggestion for future Benchmark? Would it be possible to make a smaller pattern for Pluge High, Low, Contrast, Color that are displayed towards the upper right and lower right (or can be moved around the 4 corners).

The reason I ask is that many TV's menu and sliders interfere with some of those patterns. In particular my Samsung plasma tint and color sliders are right on top of the Color pattern making it hard to adjust. However I do love that my TV comes with a blue only option to properly adjust for the 2! On this pattern it looks like the outer 2 blue bars adjust the color and the inner 2 are used to adjust for tint right?

One other weird thing I found with this pattern and my TV is that when I switch the PN50b650 color scheme from auto to custom the darker blue bars no longer match the smaller squares below them, even though custom was still at default (which should be the same as auto).

The limited / full naming is misleading as far as names go. Full is probably expanding. 16-235 gets expanded to 0-255. Values below 16 and above 235 are truncated. If this is the case, I would use limited.

If it is sending another color space, then you probably need to adjust for the new color space. One of the key things that must be done, when comparing color spaces, is to re-adjust all picture controls. Changing color spaces has tricked people into thinking one produces more saturated colors or deeper blacks than another. In reality, you need a different calibration for each. Once equalized, those differences go away.

I agree that full means expanded, but I thought that limited was the setting that truncated below 16 and above 235, not the other way around. So you are saying that expanded actually takes the value 16 and interprets it as 0, displaying something darker than it should be?

I had thought that expanded just allowed you to see otherwise invisible levels (<16, >235),while limited kept those values invisible. That is not the case? Very confusing.

So just for an example, if level 10, below video black is coming through from the source, that can be seen on limted, but on expanded it would be clipped because 16 is the new 0, so to speak?

That is why I dislike the naming. Limited sounds, well, limited.

Here is the best way to test. Put on the Dynamic range high. Switch between limited and full. You may need to adjust contrast down to see all the bars. Are the bars visible in both or just one mode? If one mode, then use that mode. If they are visible in both, then more to do.


Yes.

OK, Thanks. I actually tried both modes and could see all the levels of the Dynamic Range high pattern on both, not sure why. I tried both on the Dynamic range Low pattern as well and could see all levels if I turned up the brightness.


The thing that frustrates me the most about all of this is that there is a caption that says something like, "using Enhanced will increase the quality of the picture on HDTVs."

Sorry, I'm still stuck on this. If you're not supposed to see anything below level 16/video black anyway, then why would it matter if everything below 16 was clipped when using the Expanded RGB range option as opposed to Limited?

I mean, isn't the goal of the pluge low pattern to essentially clip everything below 16? I have read that as long as you calibrate afterwards, you should have the exact same results using Expanded that you would using Limited, but that doesn't seem to be the case; I can see a clear difference and I prefer the look of Limited.

In an xbox 360 article, I read that with RGB Limited, "blacks are displayed as gray" because of the way the TV interprets them, but that doesn't seem to be the case at all. There is so much misinformation out there.

It's nice to see below video black when adjusting the black level (brightness). Not necessary but nice. If your video chain passes values below 16 you adjust black level up until 16 appears then down until it disappears. If you don't pass values below 16 you adjust black level down until 17 disappears and then up "a click".

Of course none of this has to much to do with matching colorspace. That's your goal. If your source material is video level -- 16-235 (e.g. anything but a game) -- then ideally each step of the display chain is also at video level.