Spears & Munsil UHD HDR Benchmark 2020

Đĩa Hiệu Ứng Để Cân Chỉnh HDR Cho TV

 

Đây không phải phim điện ảnh mà là tổ hợp rất nhiều đoạn video ngắn dùng để kiểm tra cân chỉnh HDR của màn hình TV

 

 

 

Introduction
Using the tests on the Spears & Munsil UHD HDR Benchmark to adjust your display is not difficult and performing the basic calibration should take 30 minutes or less. It’s important to be methodical and careful while performing the adjustments, and to understand what to look for in each test. Before beginning you may want to review the detailed background articles about the basic adjustments found on the Spears & Munsil web site. Reading these is not required to get a good picture, but it’s helpful for understanding the theory behind each test pattern.

Preparation
Perform the calibration under the same lighting conditions you generally use to watch quality material like movies. In general, video looks best when the room is as dark as possible, but it’s most important to duplicate the real lighting conditions you will be watching under. If there are windows in the room that let in sunlight and you tend to watch movies at night, then the calibration should also be performed at night. If your display has multiple picture memories and you watch the display under multiple lighting conditions, it may be worthwhile to perform the calibration separately for each of the lighting conditions and assign each one to a different picture memory.

When you’re ready to perform the calibration, first turn on your display and Ultra High Definition (UHD) Blu-ray player and let the system warm up for 15 minutes or so, preferably playing some real material. The demo footage on the Spears & Munsil disc is a good choice, but most movies work fine as well.

While it’s warming up, gather the following materials:

• Pen and paper
• The Spears & Munsil disc (if it’s not already in the player), blue filter (optional), and this guide.
• The original remote for the UHD Blu-ray player. (we recommend not using a universal remote, as you may need to access special functions that are only available on the original remote)
• The original remote for the display (again, preferably not a universal remote)
• If the video passes through any receivers, switchers, or video processors, you’ll want the original remotes for those.
• The owner’s manuals for the player and display, and any receivers or processors that the video signal passes through.
• If you’re calibrating in the dark, you’ll want a small flashlight or headlamp to make it easier to see the remotes, paper, booklet, etc.

During the calibration, your primary location should be your normal seating location while watching movies. If possible, that location should be centered, i.e. facing the screen directly rather than at an angle, but if that’s not practical use your actual movie-watching location; don’t calibrate from the center unless that’s where you normally sit.

Take some time to familiarize yourself with the display remote. You can do this while the system is warming up; it won’t cause any harm to bring up menus and so forth during the warm-up time. Make sure you know how to bring up the video settings menus and reach the Brightness, Contrast, Color, Tint, and Sharpness controls. Consult the owner’s manual if needed. It is a good idea to write down at this point the current video setting values so if needed you can reset everything and start over. Write down every menu item, not just the five main ones mentioned above. If the display doesn’t give exact numbers for each setting, just write down their visual position as best you can, like “far left” or “dead center” or “two notches below far right.”

While viewing a pattern, you can use the left and right arrows to move to the previous or next pattern without needing to return to the menu. To return to the menu from a pattern, you can press the “enter” button or the “top menu” button. Using left and right arrows to move to the previous or next pattern is especially useful while viewing SDR patterns. The menus are always in HDR, so moving back and forth from SDR patterns to the menu causes the display to switch back and forth between HDR and SDR modes. This can take extra time.

 

 

Focus
If your display is a front projector (an independent projector that projects onto a separate screen, as opposed to an integrated “rear projector” where the screen and projector are all in the same box), you will want to check the focus, as small focus errors can mask issues and artifacts. Flat-panel displays like LCD, OLED or plasma do not have focus. Integrated rear projectors can only be focused by a trained technician.

Use your Blu-ray remote to select the Chroma Alignment pattern. Look at the five small crosshairs in the center of the screen and the four corners, and adjust the focus until the lines are as sharp and clear as possible. If your projector has motorized focus, stand close enough to the screen to see the individual pixels and use the remote to focus until the pixels are sharply defined squares. If you must stand at the projector to adjust focus, we recommend using binoculars to view the screen at high magnification while you turn the focus dial.

A few extra tips about focus:

• When the projector is completely focused, if the spaces between the pixels are distracting, as though the image looks like it’s being viewed through a window screen, it may be worthwhile to defocus the lens a tiny amount to spread the pixels slightly. Defocus only enough to reduce the gaps between the pixels; do not defocus until the pixels overlap each other.
• If it is impossible to get the entire screen in sharp focus, try to find a happy medium where each of the five crosshairs is roughly the same level of blurriness. If it is impossible to get all the crosshairs acceptably sharp, you may want to check the flatness of your screen, whether your projector is pointed perfectly centered and perpendicular to the screen, and whether the lens has any smudges or dirt on it.

Video mode settings
Once the system has warmed up, it’s time to start adjusting. Most modern displays have an overall “Picture Mode” setting, and several advanced picture settings. It’s important to get these set correctly first.

SDR First, Then HDR
Several popular displays derive their High Dynamic Range (HDR) settings from the Standard Dynamic Range (SDR) settings, so you should first run through the calibration steps below with the SDR versions of each pattern (under the “SDR 709” menu section on the Spears & Munsil disc).

You need to be sure your player is sending an SDR signal to the display and not “upconverting” the SDR signal to HDR. Check your display’s settings menu or info page, which will usually tell you whether the TV is currently in SDR or HDR mode. If you are displaying an SDR pattern, but your display is in HDR mode, look through the settings on the player to see if there’s an “HDR upconvert” setting or something that sounds similar, and turn it off. (Keep in mind that the menus on the Spears & Munsil disc are always displayed in HDR, so you need to first select and display an SDR pattern, then check the display’s menu UI to see what mode it’s in.)

Run through all the steps below with the SDR patterns. Once you have the settings correct for SDR, move on to HDR and run through the same set of steps. The instructions are almost identical in each mode; when there are differences we’ll call them out below with “SDR Only” and “HDR Only” labels.

Picture Mode
There are no standards for what these modes do, and the names vary considerably. Generally if there is a “Movie” or “Cinema” setting, that is the one to use. On some displays, the “Movie” or “Cinema” mode is preset and locks out all the other picture controls. In that case, or if there is no “Movie” or “Cinema” mode, try using “Custom,” “Normal” or “Standard.” Avoid anything that sound like it makes the picture extra-bold, like “Vivid” or “Dynamic”, or modes that sound like they’re optimized for a single purpose like “Sports” or “Game”.

 

 

Advanced Video Modes
For the most part, we recommend turning special picture “enhancement” modes off. They are usually optimized for low-quality video and bright environments, and actually will harm the picture quality of high-quality video like UHD & Blu-ray Discs when watching in a low-light environment.

Set these to Off or 0 (write down the original setting first):

• Noise Reduction/Noise Filter
• Black Tone
• Dynamic Contrast
• Shadow Detail
• Flesh Tone
• Edge Enhancement
• Black Corrector
• Contrast Enhancer
• Live Color
• Smart Dimming
• Color Enhancement
• Ambient Light Sensor
• Motion Plus/Cinema Motion/Smooth Motion/Real Cinema
• Auto Iris

If you encounter a mode with a similar name to one of the above settings, or a mode that is described in the owner’s manual as a video enhancement or improvement, it’s best to turn it off.

If you are curious to see what some of these modes do, our recommendation is to wait until the calibration and adjustment is done, then try them systematically, one at a time. Turn one on, run through the test patterns and view some video to see the results, make notes if needed, then turn it off again and move to the next. Some of them will throw off the adjustments you’ve made, and you’ll see that clearly on the test patterns. Some won’t appear to do anything obvious, which in our view means leaving it off is the safest bet.

Special cases:

• Color Temperature / Color Tone. Setting this perfectly requires test equipment, but usually if there is a “Cinema”, or “Neutral” option, that is often close to correct and is a good choice. If that is not offered, “Computer” or “Normal” are other good choices. “Cool” is not generally a good choice, as commonly it sacrifices color accuracy to get higher light output. It is worthwhile putting up the 11-Step Crossed Gray Scale pattern and trying the different color temperature settings. Any setting that makes any of the gray steps seem to have a colored tint are probably bad choices. It’s not uncommon to have more than one setting that looks essentially white. Unless you have the test equipment necessary to check color temperature, just select one that looks as neutral as possible.
• Backlight. SDR Only: This setting is adjusted using a 100% window test pattern (Windows->Grayscale->100%). You measure the window with a light meter and adjust the backlight until the window’s luminance is 100 cd/m², which is the standard for the professional video monitors used to master movies and TV shows. If you do not have access to a light meter, a good starting point is to turn it to the middle value. For HDR, don’t change the backlight setting.
• Black Level or HDMI Black Level. This should be set to “Low”, “Video”, or “Standard”. It should not be set to “Normal”, “PC”, or “Extended”.

Setting display area
To properly set this, you’ll want to bring up the framing pattern from the Video Setup menu or the Image Cropping pattern from the Advanced Video->Evaluation section, using your Blu-ray player remote. The goal is to see as much of the picture area as possible with no cropping or distortion with 1:1 pixel mapping.

When looking at the Geometry patterns from the Advanced Video->Evaluation section, each of the boxes along the top and bottom should be the same width, and the boxes along the left and right edges should be the same height. If they are not all the same, some kind of non-linear zoom is being applied; look for a “zoom”, “wide mode” or “aspect” button on the remote or setting in the video menu, and try modes until the boxes are all the same width and the maximum amount of image is visible. As a cross-check, bring up the Geometry pattern from the Advanced Video->Setup section and make sure that the squares look square and not rectangular and the circles look circular and not oval, across the entire screen.

On the Image Cropping pattern, the edges of each box should be fully visible. If some of the boxes are cut off by the edge of the screen, the display has overscan, and it’s a good idea to turn it off. Look in the menus for a “Screen Size” or “Display Area” or “Overscan” setting. Change that setting to “Full Size”, or “No Overscan” or try the various modes and controls to try to show the entire image.

The ultimate goal is to get the pixels in the disc image mapped to the pixels on your screen 1:1, so there is no digital scaling going on. To check for scaling, look at the single-pixel and two-pixel checkerboards in the center of the Image Cropping pattern. When there is no scaling being performed, they should look evenly gray, and should essentially match the gray level of the rest of the screen background. When the image is being scaled up or down, the checkerboards will have blotchy patches of dark and light, and the size of the tiny squares will vary. If you find that it is impossible to get both all the pixels on the edges visible and achieve 1:1 mapping of the pixels in the checkerboards, it is better to get the 1:1 mapping than it is to show the entire image. Small amounts of cropping on the edges will be less problematic overall than digital scaling of the image.

On some displays it will be impossible to eliminate the overscan and show the entire cropping pattern. In such cases, select the mode that shows as much of the image as possible without distortion. If the display has picture position controls, you should use them if needed to center the image on screen by moving the picture up, down, left, or right until the amount of cropping on the left matches the amount on the right, and the amount on the top matches the amount on the bottom.

Performing the basic video adjustments
The basic adjustments should be done in the following order, using the patterns listed in parentheses:

• Set a Default Color Space
• Initial contrast (Video Setup->Contrast)
• Brightness (Video Setup ->Brightness)
• Color (Video Setup ->Color And Tint)
• Tint (Video Setup ->Color And Tint)
• Recheck contrast (Video Setup ->Contrast)
• Sharpness (Video Setup ->Sharpness)
• Color Temperature (Video Setup ->Color Temp)
• Bias Light (Video Setup ->Bias Light)
• Set a Final Color Space (Video Setup ->Color Space Evaluation)

 

 

Set a Default Color Space
The PDF form you can download from www.spearsandmunsil.com and print is a handy place to write down the settings you arrive at as you work through the calibration. If your player has a setting for output color space, start by setting it to 4:4:4 Y’CbCr (sometimes just called “4:4:4”) and write your calibrated numbers in the center of the form under the 4:4:4 column, as you work through the following steps. If your player doesn’t have a color space setting, or doesn’t have a 4:4:4 color space as an option, use whatever column seems closest, or write in whatever your player calls it. Later you can come back and write down the calibration settings for the other color spaces, if there are other spaces available and if they are different.

Initial contrast
HDR Only: Broadly speaking you shouldn’t touch the contrast control in HDR mode unless you believe it is set drastically wrong. The tone-mapping algorithms used to map high-brightness content to your TV are developed with the default contrast setting, and often very little effort is made to make them work well with a different level. You can move the contrast around while displaying our contrast pattern to see what it does, but write down the default level and move it back after you’re done.

It’s also completely normal for clipping to occur in HDR mode, as part of the tone mapping process. Very high-brightness content like the test patterns on the Spears & Munsil Benchmark must be compressed and even clipped at times, and this is by design. By changing between different peak levels using the disc menu, you can see some of what the tone mapping is doing, and you can move contrast to see what happens, but there is no clear standard as to what the contrast control should do and no clear “calibrated” setting for it.

SDR Only: It’s a good idea to start by setting the contrast to a reasonable value that doesn’t clip the highlights. This ensures that other patterns and adjustments will be accurate and not thrown off by clipping.

Start by bringing up the Contrast pattern from the Video Setup section using the Blu-ray remote. Bring up the display’s Contrast control (labeled “Picture” control on some displays) using the display remote. If you haven’t already written down your current Contrast control setting, write it down now. Try raising the contrast control all the way to its highest setting. You will probably see many of the on-screen white bars blend into the background and disappear. You may also see a subtle color shift in the white background. In addition, check the color channel clipping boxes along the top and bottom of the screen. When the contrast is set too high, you will not be able to see a small darker colored box in the middle of each of them. Now reduce the contrast control until the highest bar is just barely visible, and you can see a small darker box in the center of each of the colored boxes at the top and bottom of the screen. If you can’t make the highest bar visible, or make a small darker box appear in one or more of the colored boxes, no matter how low the contrast goes, lower the bar until as many bars as possible appear. Now find the highest-numbered bar, and raise the Contrast control until that bar disappears, then lower it one notch, which should make it appear again. If not, lower slowly, a notch at a time, until that bar becomes barely visible.

Now bring up the Clipping pattern from the SDR BT.709->Evaluation section. There are six sections to check different kinds of clipping, but for this purpose, you only need to look at the red, green and blue squares. Each one should look like concentric squares of increasing or decreasing brightness. If all of the colors look like concentric squares and not a solid square, then you’re done and can move on. If one or more of the colors are clipped, try reducing the Contrast control and see if the concentric squares appear. As with the Contrast pattern, the object is to turn Contrast down to the highest setting that shows as many of the concentric squares as possible. If reducing the Contrast control doesn’t reveal any new concentric squares, then return it to the value you found using the Contrast pattern.

For more information, please read our article Setting the Contrast Control.

Brightness
Now you are ready to set the Brightness control. Bring up the Brightness pattern from the Video Setup section using the Blu-ray remote, then bring up the Brightness control using the display remote. If you haven’t already written down the current Brightness control setting, do so now.

Try raising the Brightness control all the way and then lowering it all the way and watch what happens to the pattern. With the Brightness control at maximum, on most displays you will see four vertical bars on screen and a checkerboard pattern in the background. With the Brightness control at minimum, on most displays you’ll see a completely black screen. If you never see the two leftmost bars no matter where the Brightness control is positioned, then your display or player is clipping the below-reference image data; use the Alternate Brightness Adjustment mentioned lower down.

Standard Brightness Adjustment
Turn the Brightness control up until all four bars are visible on screen. Then turn it down until the two leftmost bars disappear and the two rightmost bars are visible. The far-right bar will be slightly easier to see than the middle-right bar. If there are several settings of Brightness that make the left bars invisible and the right bars visible, you may be able to get a more precise setting by looking for the setting that makes the background checkerboard just barely visible.

Alternate Brightness Adjustment (when you can’t see the left bars)
Turn the Brightness control up until the two right bars are clearly visible. Turn the Brightness control down until the middle-right bar disappears, but the far-right bar is visible. Now turn the Brightness control back up slowly until the middle-right bar just barely appears.

For more information, please read our article Setting the Brightness Control.

Color
This adjustment is entirely optional on modern displays, and in fact we recommend not changing it. The color control was designed to compensate for problems inherent to analog video. In digital video, there should have been no reason to ever change this control, but for quite a few years display manufacturers shipped televisions that still had the same analog issues even in digital mode. In our experience, we’re finally at the point where 99.9% of modern displays get this setting right out of the box. Even if they get it wrong, it’s often not possible to fix it using the Color control. If your display has a blue-only mode or you have a filter, you can use this pattern to confirm that color decoding is roughly correct, but our recommendation is just to skip this adjustment.

For this adjustment you’ll need a colored filter or a display with a blue-only mode. Some displays do not have a blue-only mode, but it’s worth checking the advanced settings menus and/or the owner’s manual to see, because usually the blue-only mode is easier and more accurate than using the filter. If your display does not have a blue-only mode, then the Spears & Munsil blue filter is the best bet as it allows the user to select 1X, 2X, or 3X strength to help get an accurate calibration with different displays with different color spectra. Other blue filters from other companies like THX, Joe Kane, or Disney may also work, but be sure to check if they are completely cancelling the green channel before using them.

Checking the Filter Strength
The colored filter works by showing you the blue color channel only, filtering out all the green and red. Typically any filter will remove enough red to be usable, but the color spectrum of the green channel and the blue channels overlap on nearly all displays, so it’s necessary to first check that the green channel is being cancelled before using the filter.

First bring up the Color and Tint pattern from the Video Setup section and look through the 1X side of the filter. Look at the three rectangles on the left side of the pattern. Through the filter, all three should look absolutely black. If any of the rectangles look at all brighter than the black space around them, then switch to the 2X side of the filter. If any rectangle is still brighter than the background, then you’ll need to fold the filter in half to make a 3X filter. The 3X filter is nearly opaque, and to use it you may need to make the room completely dark or nearly so. This is the exception to the rule about calibrating in the same light you normally watch movies in; for this adjustment, if you need to make the room dark to make the filter work, do so.

For more information, please read our article Using the Spears & Munsil Calibration Filter.

Setting the Color control
Once you know what strength of filter to use, bring up the Color control with your display remote. If you haven’t already written down the current Color control setting, do so now. Look through the filter and watch the large blue rectangle in the upper right with a white rectangle around it as you move the Color control up and down. You’ll see the relative brightness of the blue and white areas vary. Moving the control one way will make the blue rectangle brighter, and the other way will make it dimmer. Adjust the Color control until the blue and white areas are as close in brightness as you can make them (when viewed through the filter).

Tint
As with the Color control, we do not recommend adjusting the Tint control. The instructions below are for reference if you feel like confirming that the color decoding is roughly correct.

Setting the Tint control uses the same pattern and the same filter strength you already worked out for the Color control, above.

Bring up the Tint control using your display remote. If you haven’t already written down the current setting, do so now.

Look at the magenta and cyan rectangles in the lower right. The object is to set the Tint control so that the magenta and cyan areas have the same brightness when viewed through the filter. Look at those rectangles through the filter and move the Tint control up and down to see how the brightness varies. Then adjust the control so that the inner rectangle is as close to the same brightness as the outer one, when viewed through the filter, as you can make them.

Most displays come from the factory with the Tint control set correctly or very close to it, so don’t be surprised if you don’t need to change the control at all, or only need to change it a notch or so.

For more information, please read our article Setting Color and Tint.

Recheck Color
On some displays changing the Tint control can affect the Color setting and vice versa, so you may need to move back and forth between the Color and Tint controls until the entire right side of the pattern looks the same brightness when viewed through the filter.

Recheck Contrast
SDR Only: At this point it’s a good idea to redo the Contrast control adjustment, as changes made to the Brightness and/or Color controls may affect the appropriate Contrast setting. Follow the same instructions given above to check the Contrast and Clipping patterns to set the Contrast control to the highest level that doesn’t clip.

Sharpness
The Sharpness control is perceptual, so it has no “calibrated” setting other than the one that works best for your particular display, seating position, and eyes. Sharpness is generally a good thing, but not if it makes the image look strange, so the goal is to turn it up as high as possible without adding artifacts to the image.

Bring up the Sharpness pattern from the Video Setup section using the Blu-ray remote, and then bring up the Sharpness control using the display remote. If you haven’t already written down the current Sharpness setting, do so now.

Try taking the sharpness control all the way up to see what happens. On most displays you’ll see white “halos” around the darker lines in the image, and sometimes even several concentric halos. You will also generally see that the diagonal and curved lines look stair-stepped or jagged. (You may want to get up from your normal viewing position just to look carefully at the screen and see the halos and stairsteps, but then sit back in your normal viewing position to continue the adjustment.) You may also want to turn the Sharpness control all the way down and see what happens. On most displays, the lines will be smooth, with no jaggedness or halos, but the lines will not look crisp and sharp. You are trying to strike a balance between the crisp & sharp look and the artifacts like halos and jaggedness.

While sitting in your normal viewing position, turn down the Sharpness control until the halos are no longer clearly visible and the lines look smooth and not jagged. The lines should look crisp and sharp, but should not have extraneous artifacts, noise, or blockiness.

Set Color Temperature
First see if your display has a setting for color temperature, which is sometimes called “white point.” It may be in an advanced or secondary video menu. If it doesn’t, skip this section. If it does, put up the Color Temp pattern from the Video Setup section. Try the various color temperature settings on the display to see the range available. You are looking for a setting that appears pure white, with no hints of yellow or blue. It is not generally possible to get a perfect color temperature setting without calibration equipment, but it’s usually possible to avoid the obviously wrong settings. The correct color temperature for a video display is D65, sometimes labeled “6500K”, so if there is a color temperature with one of those names, that may well be a good choice. If there are several that seem equally neutral white, select one of them in the middle of the range and move on.

Choose a Final Color Space
Many current Blu-ray players offer a range of output color spaces, for example “4:2:2”, “4:4:4”, “RGB”, etc., and most displays can handle all or most of those spaces. At some point, all video has to be converted to RGB, and the video on the disc is always stored in 4:2:0 Y’CbCr, so the choice of which color space to output from the player is really a choice as to which device will do which portions of the color conversion process. The whole conversion chain is 4:2:0 Y’CbCr to 4:2:2 Y’CbCr to 4:4:4 Y’CbCr to RGB (which is sometimes redundantly called “4:4:4 RGB”). In real processing chips, some of those steps may be combined for speed, but conceptually those are the processing stages. So if you output 4:2:2 Y’CbCr from the player, the display will do the rest, converting to 4:4:4 Y’CbCr and then to RGB.

You might think that it shouldn’t matter which device does the conversion, but it turns out that there can be large differences between different devices’ color conversion hardware. For example, some displays convert whatever they receive to 4:2:2 Y’CbCr so they can do signal processing (usually because they’re working with an off-the-shelf chip that can’t handle anything else). So if you feed these displays RGB your processing chain gets extra complex: 4:2:0->4:2:2->4:4:4->RGB->4:4:4->4:2:2->4:4:4->RGB. Since each conversion involves small degradation’s to the picture, this is not an optimal approach. With those displays, you’re usually better off sending 4:2:2 and letting the display do the processing and conversion. And that’s just one issue; there are innumerable ways that either the player or the display can make mistakes or degrade the signal in processing, making it impossible to recommend a general approach.

Clearly it can be complicated to figure out which one produces the best picture, but we’ve combined the patterns most useful for evaluating color conversion into one handy “Color Space Evaluation” pattern. Doing the full evaluation will take at least 10-15 minutes and requires making some notes. For convenience, we’ve put a color space evaluation form on the back of the disc booklet. For a larger version, you can download a printable PDF.

Performing the tests
Start by setting the output on the player to 4:4:4. If you haven’t already done so, run through the basic calibration steps for contrast (SDR only), brightness, sharpness, and color temp (and look at color and tint if you like) and write down the numbers you arrived at on the form under the “4:4:4” heading. Then switch the output on the player to 4:2:2 and run through the calibration again. You may not need to adjust anything. If your player has RGB mode, do the calibration again for that mode. If you have even more modes you may want to use a separate piece of paper or print out a second form and write in the mode name in place of one of the ones on the form.

If there are differences in calibrated settings between the different modes, check to see if the display is automatically remembering settings separately for each mode. If not, if the settings are only different by a notch or two, it’s probably not necessary to change them during the evaluation. If there are significant changes, especially in the Contrast or Color controls, you should change them as you change modes.

Once you are sure that you have the correct settings for each input picture mode, run through the various tests listed on the bottom of the form putting a check in the box to mean “pass,” and leaving the box unchecked for “fail.”

If you can select modes in both your player and your video processor, our recommendation is to start by trying the various modes in your processor, leaving the player in factory default mode. Choose the output mode that scores best and set the processor in that mode, then move to the player and evaluate all the various modes the player can produce. If you end up changing the player’s output mode, you may want to return to the processor to re-evaluate in case the input mode affects the processor’s output. If you want to be completely comprehensive, you may want to try every possible combination of player and processor mode separately.

Important note: If you are running the HDMI signal through a receiver or switcher and find problems, especially with clipping, you should try taking the receiver or switcher out of the chain and connecting the player directly to the display to see if that fixes the problem. There are several receivers, switchers, and video processors that will clip the signal passing through them, even if they aren’t doing any processing of the image. Also check the web sites of the manufacturer of your receiver or switcher to see if there is a new firmware, as this might correct some or all of the errors.

With each of these patterns, it will be easier to see the differences if you stay on one pattern and switch back and forth between the various color spaces, rather than running through each pattern with one color space and then moving on to the next color space. Some of the differences are subtle and you may need to move back and forth between the spaces a few times to really see clearly what the differences are, if any. You will also want to get near the screen for this evaluation, since these tests can involve some differences that are harder to see from a distance.

The test pattern you’ll use to do this evaluation is the Color Space Evaluation pattern, found in the Video Setup and the Advanced Video->Evaluation section of the disc. Let’s take a look at the various sections of the test pattern you’ll want to look at and what to look for in each:

Chroma Alignment
The center of the Color Space Evaluation pattern contains shapes that are designed to show any misalignment between the chroma channels and the luma channel. These misalignments can be caused by mistakes or shortcuts in the chroma upsampling, and it’s not uncommon to find that changing the format sent from the player to the display changes the amount of chroma misalignment.

Look at the eight long thin diamond shapes to the left and right of the center of the pattern. (Horizontal Alignment) Each of them has a single straight line of chroma pixels laid on top of a long skinny diamond in the luma channel. When the alignment is correct, the chroma should be centered on the diamond, and the diamond should look completely symmetrical, with the same amount of color overlap on both sides.

Now look at the four skinny diamond shaped just above and below the center of the pattern. (Vertical Alignment) Again, the colored line down the middle should look perfectly centered on the gray diamond shape.

When looking at these patterns, you may need to get right up next to the screen, because the difference can be quite subtle. Most people find it easiest to see the alignment clearly against the middle-gray background, as opposed to the black or light-gray. If you wear glasses, make sure you are looking directly through the center of the glasses, as if you look through the edge of the glasses the chromatic aberration of the lenses will shift the colors visually.

Put a check in the row labeled “Chroma alignment” for any mode where the chroma lines are centered in their diamonds. If multiple modes have properly aligned chroma, put a check for all of them. If none of them are properly aligned, put a check for the mode that is the closest to correct, or for none of them if none of them are close to correct.

Chroma Bursts
Near the four corners of the middle section of the pattern are twelve sets of thin colored straight lines, three in each corner. There is one horizontal, one vertical, and one diagonal in each corner, and each corner has a different color combination. These sets of lines are called “bursts” or “frequency bursts”. Next to each is a small “zone plate” pattern, which is a set of concentric colored circles.

The bursts should have clear, bright colors that look identical to the colors in the circular patterns next to them. If the colors are muted, or the burst looks solid gray or any other color, it shows that chroma resolution is being lost during one of the upsampling conversions. If the horizontal burst is muted, that shows a problem in the 4:2:2->4:4:4 conversion. If the vertical burst is muted, that shows a problem in the 4:2:0->4:2:2 conversion.

Another thing that’s fairly easy to tell from this pattern is the quality of the chroma upsampling being done. If the chroma upsampling is being done using an algorithm called “nearest neighbor” then each chroma pixel is just being copied four times to make the new upscaled chroma image. This is fast and easy, but produces blocky, jagged diagonal colored lines instead of smooth colored lines. Bilinear upsampling uses a linear interpolation algorithm to create the replacement pixels when it scales up the chroma channel, and looks much better. Bicubic upsampling uses two cubic interpolation curves to produce a very smooth and clean chroma channel, and is generally considered the best commonly used algorithm

Put a check in the row labeled “High-frequency detail” for all modes that have clean, bright, colorful high-resolution chroma bursts. If no modes have good bursts, put a check for the mode that has the best-looking ones.

Put a check in the row labeled “Upsampling bilinear or better” if the upsampling is clearly something better than Nearest Neighbor. You might also want to look at the diagonals and curves in the zone plate sections nearby (the four circular colored patterns in the corners) as well. Sometimes it’s easier to see the differences on one or the other depending on the specific display.

Chroma Upsampling Error
For this test, just look at the diagonal chroma bursts. If the Chroma Upsampling Error is present when you use one or more of the modes, the diagonal lines will look very jagged, or sometimes will actually have small horizontal zigzags on the edges. It can be hard to tell the difference between nearest neighbor upsampling and chroma upsampling error, but both cause jagged diagonals and both are bad, so if you’re not sure, leave either or both boxes unchecked. In general you want the smoothest chroma diagonals for the best picture possible.

After viewing this pattern with all of the different output modes selected sequentially, put a check in the row labeled “Diagonals smooth” for the mode that has the smoothest-looking diagonal lines. If they all look the same, put a check in all the boxes.

Ramps
A “ramp” is a smooth gradient of color or gray that goes from one color to another or one level to another as you move across or down the screen. There are six ramps on this pattern: two vertical ramps on each side (one luma and one chroma per side), and two horizontal red and blue ramps just above and below the chroma alignment patterns.

Each of the ramps should look smooth and even, with no bands or streaks anywhere along it. The two ramps in the center should not have a wide solid colored area in the center, but should vary from black to full red or blue at a thin peak in the center and back to black.

After looking at the ramps in each color space, put a check next to “Ramps clean” if the ramps look smooth and even with no bands or streaks.

Tracking
This section in the top center of the Color Space Evaluation pattern tells you (very roughly) if the display is following the ST2084 EOTF curve for HDR content (or the BT.1886 / 2.4 gamma EOTF curve for SDR content). If the display follows the curve perfectly, the patch in the center of each rectangle should blend in with the rectangle around them. Most displays have at least some deviations at some levels. Some deviate all the time at all levels.

In order for this pattern to work, your display needs to be able to show a single-pixel checkerboard at correct brightness levels. Some technologies can’t do this because of technical limitations, notably LCOS. There also are some displays that do some kind of internal processing that make this pattern not show tracking correctly. On such displays, you’ll get zero matching boxes no matter what version of the pattern you look at.

Each of the six boxes that make up this pattern have a solid outline that is encoded at a particular absolute brightness (for HDR) or implied relative brightness (for SDR). The inside of each box is a checkerboard using two levels that are designed to visually average out to the same level as the outside of the box, assuming the brightness tracking is correct.

To score this section of the pattern, write down the number of boxes where the center section blends cleanly with the outside of the box. You may need to move a few feet away from the display to properly see the single-pixel checkerboard blend visually into a solid shade of gray.

HDR Only: This pattern comes in different versions with peak brightness at various levels for testing displays with different capabilities. You can change the peak brightness using the settings menu or by pressing the up-arrow on the remote while displaying the pattern. Start with the lowest brightness (600 cd/m²), then try the next brightest, and so on. Versions of the pattern designed for higher brightness than your display can produce are unlikely to show perfect tracking, which is normal.

Color Space Conversion
The boxes near the bottom center of the pattern are to check a common error in doing the color conversion from Y’CbCr to RGB. All UHD signals are supposed to be converted using the equations in the BT.2020 specification, not the BT.709 specification (which is for HDTV) or BT.601 (which is for standard-definition NTSC). You should see a green ramp and a red ramp with regularly spaced boxes arranged along the length of the ramp.

At some point on each ramp, the small boxes will blend with the ramp behind. When the color space conversion is being done correctly, the red and green boxes will fade out at the same point along the line; you should be able to see the same number of boxes in each. When the color space conversion is not being done correctly, you’ll see more red boxes than green or vice-versa.

HDR Only: If the color space conversion is (correctly) being done using the BT.2020 spec, you’ll see the same number of red boxes as green boxes. If the color space conversion is (incorrectly) being done using the BT.709 spec, more green boxes will be visible than red boxes. If the color space conversion is (incorrectly) being done using the BT.601 spec, more red boxes will be visible than green boxes.

SDR Only: If the color space conversion is (correctly) being done using the BT.709 spec, you’ll see the same number of red boxes as green boxes. If the color space is (incorrectly) being done using the BT.2020 spec, a few more red boxes will be visible than green boxes. If the color space conversion is (incorrectly) being done using the BT.601 spec, many more red boxes will be visible than green boxes.
Score this test pass or fail, based on whether you see the same number of green and red boxes or different numbers. It can be hard to see the faintest box in each line, so if you are seeing only a 1-box difference, consider that a “pass.”

YCbCr Clipping
These boxes test whether the Y’CbCr channels are getting clipped at the reference high/low levels before being converted to RGB. This is always wrong; clipping should always be done as late as possible in the display pipeline, and certainly only in RGB.

If Y’CbCr is being kept intact until RGB conversion, there should be clearly visible lighter or darker small squares in the center of each of the four larger squares. If one or more of the channels in Y’CbCr is being clipped, one or more of the smaller squares will not be visible.

For more information, please read our article Choosing a Color Space.

Evaluation
When you’re done, hopefully one mode will have the most boxes checked, and most of the time that will be the preferred mode to use. In some cases, you may find that one specific issue is more distracting for you than the others, and in that case you’ll want to choose among the modes that doesn’t have that particular problem. Set the player to the mode that has the most checks in it, and if necessary set your brightness, contrast, etc. to the numbers you wrote down previously for that mode.

For a more comprehensive look at choosing a color space you may want to read our in-depth article called Choosing a Color Space.

Finishing up
At this point, you have completed the core picture adjustments. It’s a good idea to run through the entire set of patterns, quickly, just to check that everything is still correct. Some displays may have interactions between the Brightness and Contrast controls (and even other controls like Sharpness), so it’s possible that you may need to make small tweaks to the controls on the second pass through them. Once you feel confident that the controls are all set properly, it’s a good idea to write down the calibrated settings along with notes about the date, equipment, and viewing conditions. Save these settings somewhere safe so you can quickly apply them if the display gets reset for any reason.

If you tend to watch under several viewing conditions, such as a brighter “day” environment versus a dark “night” environment, you may want to run a calibration in both conditions and compare the differences. Usually they will be similar, but you may find that Brightness needs to be turned up a few notches in a bright environment to compensate for the extra light falling on the screen. If your display has multiple picture memories, you can store the two calibrations in them and switch as needed. If your display does not have multiple picture memories, you can leave the calibration set for whichever environment you use the most, or the environment where you watch the most high-quality material, or split the difference between the two to get the smallest deviation from calibrated in both environments.

If you wanted to check the effects of some of the picture modes you turned off at the beginning of this process, now is a good time to do so. As mentioned earlier, try turning them on one at a time, and running through the test patterns and viewing the video montage (under “Demonstration Footage”) to see what the effect is on the image, if anything. Some of the modes will control settings that only come into play with standard definition content, or only affect moving images and not test patterns. As before, our general advice is to leave picture settings you don’t understand to “off.” Mostly you’ll find that high-quality video looks best with the minimum processing.

That’s it! Please let us know if you have comments or suggestions on the disc, the instructions, our web site or anything at all.