Home Theater & Sound "Video Noise"

Video Noise

November 2009

I Want to Make My Picture Better: Part One

So you have this HDTV and you’ve been watching it for a while, but you’re getting a nagging feeling that the picture isn’t as good as it could be -- and you’re not sure how to improve it. In fact, you’re not even sure you’d know if it was better once you start messing with things. If that sounds familiar, this month’s and next month’s columns will provide some guidance.

First, let’s define better. In my world, better means more accurate. That is, the TV more accurately represents the movie or TV program as it was originally captured. Video is very well defined in terms of quality. There are standards for colors and shades of gray; shadow detail should be visible and not crushed into black; highlights should be visible and not blown out or too dark; and color shouldn’t be too intense, unless that’s how the movie was intended to look. Every shade of gray should be as close as possible to the D65 point, which in the world of xy color coordinates is x=.3127 and y=.328. You may have heard that 6500K is the ideal color temperature, and it is. But color temperature doesn’t account for green. In fact, you can achieve a color temperature of 6500K and still have way too much or too little green. So instead of obsessing over color temperature, we should focus on the D65 point, which ensures that red, green, and blue are all in proportion, producing proper shades of neutral gray and white. There are test patterns for measuring grayscale steps and color, while other patterns help you adjust your controls by eye so you can improve their accuracy without actual measurement.

To improve your picture, you have four options. You can:

Adjust the user-menu controls by eye
Adjust the user-menu controls with the assistance of a test/setup disc in your Blu-ray or DVD player
Purchase a colorimeter and software, and learn how to calibrate your own TV
Hire a professional calibrator

This month, we’ll cover the first two options.

Adjusting your menu controls without assistance

I’d like to offer guidance for adjusting your controls, but it’s a real crap shoot when you have no reliable reference. All I can suggest is that you disable all the controls in the user menu that have automatic or dynamic in their name. Set the sharpness control to about half of the factory default value. If the factory setting is 50, set it to 25. If the control is set to zero and can be lowered to -30 and raised 30, you’ll never really know what the best setting is without a test pattern. Ultimately, a test pattern is the only way to know where it should be set. Sometimes zero is the right setting; other times it isn’t, but only a test pattern will reveal the appropriate setting.

Any noise reduction or NR controls can almost always be set to Low (or On if your only choices are On and Off). A few years ago these controls were so severe that they often did more harm than good, but manufacturers have started providing settings that can be used without harming good images. Noise-reduction settings typically operate only on standard-definition programming, and conservative use of them in newer video displays can actually be helpful. That said, setting them to Medium or High will often impair quality. If you have a mode called Cinema, Movie, THX, Pure, or Theater, select it. And if you have color-temperature settings like Warm, Neutral, Standard, and Cool, the Warm setting will often be the most accurate. Be aware, however, that if you’re used to the Cool setting, which makes the picture too blue, the Warm setting might seem overly yellow for the first few days. Neutral may be the best choice for a few HDTVs, but try Warm first. If it still seems too yellow after three days, switch to Neutral.

Factory settings are almost always terrible for image quality, and modes named Vivid or Dynamic are likely to be the worst choices. Again, we’re assuming here that the highest-quality image is the most accurate image. So if you’re watching football, the grass, uniforms, crowd, and sky should look like what you’d see if you were at the game. But looking accurate doesn’t always mean looking great. Take night games, for example. Some stadium lights will make grass look blue -- even in person -- so adjusting the image to create a vivid green will likely throw off the rest of the picture.

Adjusting your menu controls with a setup disc

If you’re not very technical, the Monster (yes, that Monster) HDTV Calibration Wizard setup disc (DVD format) is probably your best choice. Everything it helps you with relies on simple photos or simple moving images. You won’t learn much about your HDTV, but it will help you adjust some controls much better than if you had no help.

If you want to learn more about your HDTV and how images are made, as well as how controls will change the images, Digital Video Essentials: HD Basics (Blu-ray) is by far the best disc out there. Shop around and you’ll find it for as little as $16 from some reliable mail-order sources. As an example, the disc will walk you through setting the brightness control, and if you ever need to recheck it, you’ll be able to watch the tutorial again or go directly to a test pattern.

200911_spears_munsil.jpg (23584 bytes) If you already know the setup basics and you want a more technical disc, Spears & Munsil’s High Definition Benchmark: Blu-ray Edition is about $25 at most mail-order outlets. It doesn’t offer all the behind-the-scenes information and explanations that you’ll find on the Digital Video Essentials disc, but if you already understand the basics, the Spears & Munsil disc is the next level, technically.

When you use one of these discs in a disc player, it’s important not to have made any adjustments to the disc player that will alter the video. The machine should simply send the disc’s data to the video display. This doesn’t always happen, as some players have setup menu choices that can alter the video in undesirable ways. For example, some Sony Blu-ray players let you choose between Theater Room, Standard Room, or Bright Room. Among these, the only setting that won’t change the video encoded on the disc is Standard Room, so you should never use the other settings. If you own a disc player and you aren’t sure what some of the settings are, or if they alter the video, you can search online owner forums for your particular machine and hopefully learn from other owners what your settings will do and whether they’re useful.

Next month we’ll take a look at your remaining options for improving your picture.

. . . Doug Blackburn
db@hometheatersound.com

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