AVPro Edge

Aug. 1, 2022 - While a good many people experienced flight delays around Memorial Day and onward, at least one guy had a clear shot on the highway to the danger zone. Top Gun: Maverick, finally debuting after a nearly three-year delay, has kept Brinks drivers working overtime by dominating the early summer cinema box office. The long-awaited sequel to Top Gun (thirty-six years…but who's counting) during heavy release promotion, urged theatrical viewing in an IMAX theater. I admit an eager desire in attending however, what for me has to be one of the most inexplicable Hollywood decisions since United Artists and Universal both turned down Star Wars, IMAX theaters run a movie a mere two weeks, only to then change features.

As of this writing, Top Gun: Maverick has grossed over $1Billion dollars…that's a lot of folks feeling the need for speed. Perhaps an epiphany of sorts, I noticed the IMAX cinema local to the AVPro St. Petersburg office once again has the film booked. Nonetheless, film aficionados continue making the pilgrimage to IMAX cinemas for a first-hand experience they cannot duplicate in the home. Or is that in the process of changing in a big way? Let's follow Mav for a few clues.

IMAX, EH?

Worldwide, there are approximately 1,600 IMAX-capable cinema facilities licensed by the Canadian firm, with most differing substantially from the original IMAX concept of near-total audience envelopment in their "Classic Design" dome and Omnimax theaters, both contributing to establish the concept at exhibitions and world fairs since the 1960's. As purpose built structures, these theaters featured steep row angles placing the audience much closer to the screen in comparison to conventional movie theaters, this capability due to 12K resolution delivered by the 70mm film format exclusively utilized at the time (technically, 65mm film in the camera, printed on 70mm film for projection).

Today, the majority of IMAX-specific theaters are in retrofitted auditoriums reflecting the "Multiplex Design" concept, presenting studio theatrical releases which have undergone the IMAX DMR process (more on that below). These facilities tout laser projection and 1.91:1 screens (compared to the Classic Design, 1.43:1 aspect ratio suited for IMAX film cameras and their unconventional application of the 70mm film format) which better accommodate Hollywood's offerings. One difference readily noticed by those who've previously visited an original Classic Design venue is the resolution drop to one third that of 70mm film, from the present use of 4K laser-based digital projectors. 

Though not pertaining to IMAX Enhanced for the home, it merits mention that IMAX 70mm is, literally, a 90 degree departure from Hollywood's initial attempt, that being Fox Film Corporation's 1929 introduction of Fox Grandeur, the original 70mm film format. The film path for the Fox method was vertically through the projector, identical to the 35mm Academy Format. Referred to as 15/70 film, derived from the 15 parallel sprocket perforations per frame, IMAX film is projected horizontally from a platter designed to support the substantial weight of a full length feature. Differing also from traditional Hollywood formats where film is unspooled from the outer circumference inward, IMAX uniquely is the complete opposite, travelling outward from the inside circumference at 6 feet per second. IMAX raw film has a cost of $3.00 per foot, or $18.00 per second of viewing time. Today, nearly all IMAX theaters use proprietary laser-based digital projectors supplied by Barco, with filmmakers utilizing IMAX certified digital cameras from Arri, Panavision, Red Digital Cinema, and Sony. None have the 12K resolution of 70MM film, but those days are approaching as fast as an F/A-18 Super Hornet. Black Magic introduced a 12K digital camera at 2022 NAB this past spring, which awaits certification. 

BIG PICTURE + BIG SOUND

Some years back on September 4th, 2018, IMAX and DTS announced their coming together with, as worded in the press release, the creation of the first single certification for both home theater video and audio gear called IMAX Enhanced (IE). The partnership aims to capture the heightened cinematic experience IMAX visually delivers, coupled with the visceral impact of a DTS soundfield, converting your viewing room into Hollywood's TCL Chinese Theatre. Leading consumer electronics manufacturers quickly adopted the format, introducing AVR's, surround processors, televisions and some speakers earning IMAX Enhanced certification (speakers weren't required to do anything different, such as THX with directionality and frequency response control, just be able to adequately handle the full-range signal). But as the fanfare subsided and content thinned, so it seems did demand. It just may be that Top Gun: Maverick, sure to be released on IMAX Enhanced UHD Blu-ray, will rekindle a keener interest in this largely dormant, um… well, what do you call it? It isn't a format per se. For Audio, IE uses DTS:X, an existing surround format onboard nearly all modern AVRs. 

Video-wise, theatrical content undergoes improvement during a process called Digital Media Remastering, though on the consumer side nothing more than an HDR requirement prohibits viewing IMAX Enhanced streaming or discs on suitable displays. Nothing is overly-demanded of IMAX Enhanced video hardware, apart from confirmed, superb performance manufacturers design into top-tier displays, which in turn are certified by IMAX. IE stipulates a 4K HDR10 display, capable of proper calibration and correctly calibrated, will likely pass IE's certification process. Certification assures the display will recognize the IMAX Enhanced flag, intended to launch video displays into the most appropriate viewing mode for 24fps content, disabling all processing features that allege image fidelity improvement. As any accomplished calibrator can tell you, as well as demonstrate, these features largely do the opposite. Typically, "movie" or "cinema" mode from most manufacturers – certainly in their best offerings – also turns such things off. IMAX and DTS are counting on the cumulative employ of an IE certified chain of products, working in unison, to exhibit the declared strengths of the DMR process in the consumer's home.

IMAX DMR and What It Does

Xperi, owner of DTS since 2016, indicates the audio track for IMAX Enhanced is specifically remixed from the IMAX theatrical file for playback on consumer equipment. Metadata includes an encoded flag which signals a certified DTS-X equipped processor to playback the mix as prescribed by the IE DMR process. The unidentified crossover frequency used is roll-off specific to IMAX Enhanced sound tailoring, and only used with IMAX Enhanced program material on certified audio products. Metadata does not perform channel steering, nor does it contain objective audio enhancements for the main channels. All content below the crossover point is diverted to the LFE channel, with the IE mode performing additional enhancement to the LFE channel through the certified AVR or processor, compared to when IMAX Enhanced is disabled. In IMAX theaters, the sound system can be as much as 12.0 full range channels (no dedicated LFE, all channels encompass the entire audio spectrum, just as a pair of floor-standing, full-range, hi-end stereo speakers like Wilson Audio Specialties or MBL might). 

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By Michael Hamilton