Editor's Note: Each Friday, High-Def Digest's own HD Advisor will answer a new round of questions from our readers. If you have home theater questions you need answered, send an email to HDanswers@gmail.com.
Answers by Joshua Zyber
IMAX Digital Theaters
Q: I was extremely disappointed in the IMAX digital showing of the new 'Star Trek'. I went expecting the 70mm experience, and found it was basically a 2-projector digitally produced image. Although I have not compared it to the “standard” theater release, I did some research and found there is a great deal of controversy about the IMAX label being used on something seriously inferior to 70mm IMAX film. How do you weigh in on this?
A: As you've noted, there are two types of IMAX theater out there. The original IMAX configuration consists of huge screens (approximately 72'x53'), and movies projected from 15-perf, 70mm film stock (referred to as IMAX 15/70). IMAX film has a frame size almost 10 times larger than traditional 35mm, and even 3 times larger than standard 65mm stock. Content natively shot on IMAX film, such as the nature documentaries and short subjects that routinely play in IMAX theaters, exhibit breathtaking clarity and detail when projected in their original format.
When Hollywood movies shot on 35mm film are projected in IMAX 15/70 theaters, the image is blown up to the larger film stock through a process known as "DMR," which stands for "Digital Re-Mastering." (Yes, the letters are jumbled, but "DRM" is already an acronym for "Digital Rights Management," which is something else entirely.)
In recent years, the IMAX corporation has shifted to digital projection. Newer IMAX theaters utilize two 2k-resolution DLP projectors. Digital IMAX theaters also usually have much smaller screens, averaging 58'x28'.
Personally, I'm with Aziz Ansari on this. I feel that digital IMAX theaters are essentially false advertising. The company lures audiences in with the IMAX name, which promises a huge screen theatrical experience. What you get instead is a screen barely larger (sometimes not even) than a standard theater, using projectors the same resolution as any other DLP cinema. The company does not distinguish one type of theater from another in its branding. You have to do your research beforehand to find out which type of IMAX you'll be getting at an IMAX theater. Really rubbing salt in the wound, most theaters add a surcharge to IMAX ticket prices.
Furthermore, I have to say that I'm not a fan of the DMR upconversion process, regardless of whether the results are projected in a 15/70 theater or a digital theater. (I have confirmed with IMAX that movies projected in their digital theaters also undergo DMR upconversion.) From their own description of it (emphasis mine):
"The image on a 35mm film frame is comprised of a fine grain structure like that of all photographic images. This grain when projected on to the IMAX screen looks like a TV channel that isn't quite tuned to the station. Removing this grain while preserving the quality of the underlying image is the basis of IMAX DMR.
To create the brightness and clarity that audiences have come to expect from The IMAX Experience®, IMAX uses a proprietary computer program to make the images sharper than they were originally, while colors are adjusted for the unique technically superior characteristics of the IMAX screen."
In other words, to convert 35mm movies to the "IMAX Experience," the company digitizes the footage, applies Digital Noise Reduction to remove grain, and then applies artificial sharpening and Edge Enhancement to sharpen the picture back up. You'll note that, in our Blu-ray reviews here at High-Def Digest, we frequently complain about the negative consequences of DNR and EE in video transfers. As bad as those artifacts look on your HDTV at home, the problems are only magnified on a large theatrical screen.
IMAX will argue that the proprietary computer programs they use for the DMR process are more sophisticated than those used for home video. I beg to disagree. Every IMAX DMR presentation I've seen has exhibited an obvious lack of textural detail and consistent (often severe) edge ringing artifacts.
As a videophile, I do not recommend viewing Hollywood movies in an IMAX theater, except for special cases where portions of the movie were photographed on real IMAX film, such as 'The Dark Knight' or 'Transformers: Revenge of the Fallen'. In those instances, you should seek out an IMAX 15/70 theater. In digital projection, the IMAX sequences are downconverted to the same 2k resolution as the rest of the film. However, be warned that, as good as the IMAX scenes in those movies will look in 15/70, the rest of the 35mm footage will have undergone DMR tinkering.
For my money, I prefer to view 35mm movies in a quality 35mm theater rather than an IMAX theater. If the movie was photographed digitally or utilized a Digital Intermediate during post production, the best option is to find a good (non-IMAX) DLP theater, which will project the original digital file provided to them by the studio, rather than a DMR'ed manipulation of it.
Region-Free Blu-ray Playback
Q: I assume you have region-free Blu-ray capabilities as I've seen you review imports in the past. I've been looking into getting a backup player which is not region locked or at least switchable. The other issue is my trusty old DVD player is dying and preferably any multi-region Blu-ray player would be multi-region for DVD as well... and if it's at all possible, throw decent DVD upscaling into the bargain. Most of my Googling around on this issue has thrown up two options: very cheap and nasty looking south-east Asian units which look like they'll fall apart out of the box, and very expensive professional modifications of brand name players which presumably void the warranty. What other options have you found?
A: I'm only aware of two Blu-ray players that can be made region-free for Blu-ray playback out-of-the-box just by entering special codes on the remote control.
I use an LG BH200 Blu-ray/HD DVD combi player for this purpose. I managed to pick one up at the tail end of the model's life cycle, when it was being blown out at discount prices by the Best Buy chain. With the right sequence of numbers on the remote control, the player can be switched to a designated region. (There is no "all-region" setting, so you may need to change the region depending on the disc being watched.) In addition, the player also has excellent DVD upconversion from the QDEO processing chip. On the other hand, the unit has a number of quirks. If you play a disc with 50 Hz content on it, the player cannot convert it to 60 Hz. You will need to connect the player to a display compatible with 50 Hz signals. Also, the unit has a reputation for being glitchy with many newer Blu-ray discs, and HD DVD discs in general. Unfortunately, the model is long-since discontinued, and LG's firmware support for it is sketchy at best.
Recently, the Momitsu BDP-899 hit the scene, likewise promising region switching with a remote control sequence. From my understanding, it has a similar limitation regarding 50 Hz content. I have not used this player myself, and cannot comment on its quality. Given Momitsu's history, I wouldn't expect much out of its DVD upconversion. Prior Momitsu DVD players were based on poor, flag-reading deinterlacing chips.
The other option is to buy a brand name player that's been hardware modified to remove region restrictions. As you've found, these tend to be very expensive, and the modification voids any manufacturer warranty. Also, depending on the model, you may find that some don't support 50 Hz content at all.
Although I'm not at liberty to post the details (please don't email to ask; I won't respond), I've heard that there is a bootleg firmware available for one recently-released Blu-ray player that will allegedly hack it for region-free playback at no extra expense. I have not actually tried this firmware myself. Again, this modification is not authorized by the manufacturer, and will void the warranty. Attempt it at your own risk.
DTS-HD Master Audio on 'Terminator 2'
Q: I recently purchased the 'Terminator 2: Skynet Edition' Blu-ray. It has a 6.1 DTS Master Audio soundtrack advertised on the box. When playing this Blu-ray, my Denon 3808CI shows 6 channels as being input, so it looks to me like its 6.1 discrete channels. However, there is some discussion in the forums that claim this Blu-ray disc is really a 5.1 soundtrack with a matrixed sixth channel, like some DTS-ES DVDs use. For DTS Master Audio, are all channels always discrete? Or, does the DTS MA spec also allow for matrixed channels, like the DVDs have? And, specifically, does this 'T2' Blu-ray actually have a 6.1 discrete channel soundtrack, or a 5.1 soundtrack with a matrixed sixth channel?
A: The DTS-HD Master Audio spec allows for up to 7.1 discrete channels of audio on Blu-ray. According to this post at the Home Theater Forum by disc producer Van Ling, the Master Audio soundtrack on the Skynet Edition Blu-ray of 'Terminator 2' is a 5.1 track with a matrixed sixth channel.
Some questions that the HD Advisor receives are best answered by our readers. If you can help to answer the following question, please post your response in our forum thread linked at the end of this article. Your advice and opinions matter too!
CCFL Backlights in LCD TVs
Q: Why do a lot of modern LCD TVs employ some form of CCFL strobing for adjusting the level of the backlight? For those that are sensitive to this, setting the backlight lower produces a visible rainbow effect in high contrast scenes, not unlike what was seen with DLP displays. Do LED backlights dim via the same method?
Check back next week for another round of answers. Keep those questions coming.
Joshua Zyber's opinions are his own and do not necessarily reflect those of this site, its owners or employees.