Tuesday, October 14, 2008

Tech Note: Iron Man on Blu-ray Disc

I recently received my copy of Iron Man on Blu-ray disc and made an interesting discovery. You may have read about this on forums already but I'm talking about it here for those that don't want to wade through the 3,000 post mega-threads on AVS. As you probably know, the Blu-ray release of Iron Man was recalled at the last minute due to an authoring error. Apparently, some reviewers had trouble with their pre-release copies. I found in my research that there is an old and new UPC code and the old one was covered by a decal when the disc was replaced by the manufacturer. Well, there is still a quirk with the replacement disc that I discovered when I viewed the film.

Iron Man includes an excellent Dolby TrueHD soundtrack. Unfortunately those of us who own certain model receivers (Onkyo 805 in my case) will note that the sound lacks the punch and dynamic range we've come to expect from lossless sound mixes. I watched the entire movie and felt underwhelmed by the sound even when I turned it up quite high. I remembered an early review I'd read which said the standard Dolby Digital track actually had more punch and the TrueHD track was enabling Dynamic Range Compression automatically. I played the movie again checking the Late Night mode on my receiver. Sure enough, it was set to Auto. Turning it to Off made a huge improvement. I watched the movie through two more times and was much more impressed. I also discovered that powering down the receiver resets the Late Night mode on all TrueHD tracks to Auto. I have to manually turn it off for every Blu-ray that has Dolby TrueHD. Auto doesn't always mean compressed but Off is a guarantee that there won't be any range compression. I had always wondered why some TrueHD movies required a higher volume level than DTS Master Audio. I believe I now know why. By the way, this only applies if you're bitstreaming the audio. Analog or PCM won't exhibit this behavior.

Advice: check the Late Night setting on your receiver every time you watch a TrueHD enabled movie. You don't have to worry about DTS because Late Night mode is only for Dolby codecs. This may also not be the case for all receivers and processors. I believe Onkyo and Yamaha use the same DSP chips so you Yamaha owners might want to check this out the next time you watch Iron Man.

Thanks for reading and enjoy the view!

Thursday, October 02, 2008

The Samsung Color Management System

Samsung's newest flat panel TVs are quickly becoming a reference standard for calibrators. The user menu boasts the most complete set of adjustments I've seen outside a projector. There is even a comprehensive color management system (CMS). These controls are available on all Samsung 1080p TVs, LCD and plasma, 32 inches and up. As mentioned in other articles on this blog, there are also controls for gamma and white balance. It's so nice not to have to navigate an arcane service menu to find these adjustments. With the user menu, I can achieve a nearly perfect calibration in all respects. In this article, I'd like to focus on the CMS. I recently learned a new technique that has allowed me to achieve a high level of color depth and reality. Thanks to Doug Blackburn, Widescreen Review writer and ISF calibrator, for his research and instruction on the new Samsung CMS.

A CMS has two major goals: achieving the correct colors and the proper amount of each color. In layman's terms, you want the three primaries and three secondaries to match the SMPTE standards on the CIE triangle. This standard is also referred to as Rec 709 which is the HD color space. Most TVs with a CMS allow you move the color points to make this happen. What Samsung allows which is a real plus on a consumer TV, is adjustment of the luminance of each primary. There is a standard for that as well but most CMS equipped TVs won't allow adjustment of the color luminance independently. Below is a CIE chart from a 650-series LCD.

It's not absolutely perfect but I've never been closer on any other TV. What the CIE chart doesn't show is the luminance of each color. That is the third axis that I can now address thanks to Samsung. By using a luminance calculator, I can input the actual measurements of each color at 75IRE and find out what the luminance should be. My initial measurements on this TV showed the luminance levels to be about 20% too high for green and blue while red was almost perfect. You can see what needs to be done: the balance must be restored! By using the Custom mode in the Color Space menu, I can adjust each color individually. Once I dropped the luminance of green and blue, I had each color within .5fl of the correct number.

The net effect is a more realistic color representation. The "looking through a window" effect is heightened and the sense of depth and dimension in the image is greater. You see, low black levels aren't the only thing needed for a great image! Samsung has added a feature that makes their TVs truly capable of unprecedented image accuracy. Thanks to the ISF, the community of independent calibrators and probably influential internet forums like AVS, manufacturers are finally delivering displays that offer accurate image modes in addition to their retina-searing showroom ones. These latest Samsung panels can provide an image to rival any professional monitor. I have revisited the current-generation Samsung TVs I've calibrated to adjust the CMS and I now employ this technique on all Samsung flat panel calibrations.

Thanks for reading and enjoy the view!