Is Dolby Cinema the new THX

How the movie theaters defend themselves against home cinema and streaming

The cinema industry has fluctuated between desperation and euphoria in the past few months: the complaints at the beginning of the year that 2018 had not sold so few tickets in this country as in decades were followed by jubilation over the outstanding box office result of the film "Avengers: Endgame".

The assessments of the future of cinema are similarly divided. There is only one thing they all agree on: The greatest threat to the cinema is video streaming services - above all Netflix with its own films such as "Bird Box" and "The Highwaymen", which would have previously been shown on the big screen . But that's not all, you get the blockbusters on Netflix in 4K resolution, with an extended color space and increased contrast range (High Dynamic Range, HDR) and 3D sound. As a result, the picture and sound quality in a lovingly furnished home cinema is better than in the average cinema.

The cinema operators have to come up with something to keep attracting visitors. So-called “Premium Large Format” (PLF) halls have been gaining ground for some time. They offer large, floor-to-ceiling screens, sophisticated all-round sound systems, comfortable armchairs and other amenities. In 2018 there were around 3370 PLF screens worldwide.

The trend is also noticeable in Germany: the first cinema in Germany opened in Munich's Mathäser Palast in mid-May, which was converted into a "Dolby Cinema" according to Dolby specifications. Shortly before, IMAX - with a current global market share of almost 65 percent, is clearly at the top of the PLF and also represented in five locations in Germany - that it would install the world's largest screen by 2020 in Leonberg near Stuttgart.

The new movie palaces

Today cinema operators can choose between practically turnkey PLF systems from countless suppliers. In contrast to IMAX and Dolby, German cinema-goers should not be familiar with many names. The Chinese company CGS, number 2 in the world market, is primarily represented in its home country.

This year, however, some old friends have been added: Sony celebrated its world premiere with its “Sony Digital Cinema” in January at the “Galaxy Theater” in Las Vegas. THX, formerly a real house number in the cinema with the seal of approval of the same name, wants to re-establish itself with “THX Ultimate Cinema”: At the end of March, the company announced that it would be opening a hall of the "Regency Village Theater" in Los Angeles that would be furnished according to its specifications by summer opens. THX has won CGS as a partner for this.

It is difficult to establish a generally applicable rule as to the size of the canvas from which it falls under the "Large Format" category. The model in Munich's Dolby Cinema is around 15.7 meters wide, while the screen in the Dolby Cinema in Eindhoven is 20 meters and that of the Sony Digital Cinema in Las Vegas is 21 meters. IMAX, on the other hand, only speaks of “large walls” from a width of just under 23 meters; the model in Leonberg is said to be around 38 meters wide.

In addition, IMAX developed an image format with an aspect ratio of 1.43: 1 for its analog 70 mm format, which requires particularly high screens. Even if the digital variants of the system only offer 1.90: 1 as an alternative to the usual digital widescreen format 2.39: 1, the height difference in the picture is still considerable: over a width of 20 meters it is 2.10 meters.

Currently all systems work with projection, a double laser installation is common in order to achieve a usable brightness on the large screens - even with 3D films. In some cases, proprietary technologies are also intended to get the most out of laser technology.

Dolby Cinema

Dolby designed its PLF system as a complete package: cinema-goers want to be transported into another world before the film starts. Therefore, one does not enter the hall directly, but through a small passage, in which a clip produced for the film with a suitable sound is projected across the wall.

The image technology called "Dolby Vision" includes a special technology on the two 4K projectors that ensures a completely free light path. So no filters are used, nor is anything mounted in the front of the lens. According to Dolby, the result is a maximum brightness of around 106 candelas per square meter (cd / m2), converted to 31 foot Lambert (f L).

Conventional 2D projectors usually only achieve just under 48 cd / m2 (14 f L), which is reflected in the recommendation of the Digital Cinema Initiatives (DCI). In the case of 3D projection, only half is left at best. In Dolby Cinema, on the other hand, 3D films run at around 48 cd / m2. This allows relaxed 3D enjoyment, as the eyes are not so strained in dark scenes.

An equally important factor is contrast, which describes the relationship between the darkest and the lightest signal level. With a normal cinema projection with xenon lamps, this is around 2000: 1 and often only goes up to 3000: 1 with lasers. With Dolby Vision, the projectors create over a million to one, according to Dolby.

To avoid stray light, the hall and furnishings are anthracite / black; only a blue strip of light on the walls and blue lamps on the steps provide lighting before the performance. Care is also taken to ensure that the light strips on the floor pointing the way to the exits do not shine unfavorably. Finally, the projectors support the extended BT.2020 color space for richer colors.

As expected, Dolby relies on its latest, object-oriented surround system “Dolby Atmos” with up to 64 separate channels for the sound. This allows the usual side and rear loudspeaker arrays to be broken up and the surround boxes to be controlled individually instead. There are also ceiling speakers for height effects.

IMAX with laser

In 2008, IMAX dared to make the leap from analog 70 mm film to digital projection under the name "IMAX Digital". The implementation, however, received criticism because the system used two xenon projectors with a resolution of only 2K each. A few years ago the company brought out a revised version with “IMAX with Laser” with 4K models. This technology is used in Berlin, Karlsruhe and Sinsheim and will also be used in Leonberg.

What has remained is the approach of projecting the images from both projectors superimposed with a tiny offset and increasing the perceived resolution - an important point with the large screens. In IMAX halls with laser projectors, screens in 1.43: 1 format will be installed again in order to be able to show digital versions of the “classic” 70 mm productions, for example.

According to IMAX, your laser projection system has a brightness of 22 f L (around 75 cd / m2) and is thus well above the DCI recommendation of 14 f L (48 cd / m2), but behind Dolby Cinema with its 31 f L (106 cd / m2, see above). When asked about this, IMAX CTO Brian Bonnick told c’t that "IMAX with Laser" provided a sharper image that also had a higher contrast within the image.

This is achieved through high-quality lenses and our own projection technology. It completely dispenses with the glass prism, which is otherwise mounted in the front of the micromirror array (DMD) in every projector with a xenon lamp or laser. The DMD then directs the light back through the prism to the screen.

Instead, IMAX sends the red, green and blue laser light in a patented light housing directly onto the mirrors - thus ensuring that the bright areas in the image do not lighten the dark ones. The case is also made of Invar, a very heat-resistant iron-nickel alloy. According to Bonnick, this construction can be cooled much better, so that the otherwise usual deformations on the mirror mountings and the associated blurring do not occur.

According to Bonnick, it is just as important that the IMAX system automatically calibrates itself between performances. The technology in the hall is also connected around the clock to the IMAX service center, which monitors all system components and sends technicians in case of problems.

The automatic calibration also includes the 12-channel sound system that IMAX developed for the "IMAX with Laser" rooms. Specifically, it works with seven full-range speakers (instead of the typical combination of satellite speakers and subwoofers) on the lower level, four height speakers (ceiling speakers) and a height center. The latter makes sense because the very high IMAX screens also offer effects that run from the lower to the upper center. According to Bonnick, the system has sufficient reserves to (automatically) compensate, for example, the failure of a woofer in such a way that the audience does not notice any restriction in the sound reproduction.

ScreenX

The "ScreenX" system from the Korean group of companies CJ, which promises a 270-degree viewing experience, plays a special role. For this purpose, the normal screen is extended to the right and left by additional projection screens - ideally in a ratio of front (width of the screen) to the sides (front edge to the last row of seats) between 1: 1.5 and 1 : 2. There are already around 200 converted cinema halls in 18 countries, including Switzerland and France. German cinemas have not yet been included.

Since 2018, CJ has also been offering ScreenX in combination with its "4DX" system, which was previously offered separately, in which the cinema seats move in line with what is happening on the screen and other effects such as wind and fog are triggered.

At the end of February, CJ announced that upcoming ScreenX cinemas will exclusively use the DTS: X 3D sound system. However, this agreement does not affect the 200 existing installations worldwide, which are still not tied to any particular sound system.

Cinema LED screen

The general equation "Best image quality only with double laser projection" has not been valid for two years: The first cinema room opened in which a DCI-certified LED screen was used instead of projection technology. When it comes to the “Cinema LED Screen”, which Samsung markets under the name “Onyx”, some people might think of the “The Wall” screen, which has already been presented several times at trade fairs. In fact, both are made up of individual modules, but The Wall is aimed at the home and office market and works with smaller LEDs.

Onyx started with a 10.3 meter wide and 5.4 meter high model, which can also be found in two German cinemas (in the "Kinopolis Main-Taunus" in Sulzbach and in the "Traumpalast Esslingen"). A 14-meter-wide version has also been running in a Beijing cinema since the end of 2018 - which indicates that LED projection screens will be able to play in the PLF category in the future.

The screen area of ​​the Beijing LED wall is almost twice as large as that of the smaller model, but nothing has changed in the 4K resolution. Samsung gives the maximum brightness for the 14-meter version with 88 f L (around 300 cd / m2) at. The screen only runs at full speed for 3D films, around 67 f L (230 cd / m2). That's still more than double the 2D value of Dolby Cinema. In addition, according to Samsung, the screen beats the specified contrast ratio for Dolby Cinema of over a million to one.

The good brightness and contrast values ​​have another advantage outside of film operation: The screen walls can be used for conferences and e-gaming events where the hall cannot be completely darkened.

Samsung is open about the sound. Although the manufacturer offers cinema operators a suitable solution from its subsidiary Harman, a DTS: X 3D sound system is being used for the first time in Beijing. Like Dolby Atmos, it works with audio objects and height channels.

Samsung is unlikely to remain the only provider. Sony presented the prototype of a cinema screen at a cinema fair in 2017. NEC, Barco, Christie and LG should also have their eyes on screen walls as a potential business area.

Suitable material

All laser projection systems and screens have one problem in common. It is true that every film camera from the cinema sector is able to deliver an HDR image. However, if you play the currently available DCI copies via the systems, you only get an image with the usual contrast range (Standard Dynamic Range, SDR). In this respect, special versions are needed in order to be able to show what the solutions really do.

For Dolby Cinema, versions of films with images in HDR format Dolby Vision and 3D sound in Dolby Atmos are produced. 40 films have been announced for 2019 so far. This should not be confused with titles that only offer Dolby Atmos sound, as these are also shown in normal cinemas.

IMAX has to put in more effort because the films are brought to their own aspect ratio of 1.91: 1 - although it should be noted that some films are already being produced at least in part appropriately with regard to this utilization. IMAX ’proprietary" DMR "system (Digital Media Remastering) also includes a noise reduction algorithm, as the film grain can have a disruptive effect on the big screen in HDR. In the interview, however, the IMAX CTO emphasized that the filmmakers would decide whether and to what extent the noise suppressor should be used.

According to US media reports, THX expects 30 specially mastered films for "THX Ultimate Cinema". There is still no concrete announcement for Sony Digital Cinema, but the head of Sony's cinema division has already stated that the possibilities are currently being explored. So far nothing is known of special film mounts for Samsung's LED screen.

With ScreenX, the effort is as expected, greater and the collaboration with the studios even more important, as it requires material for the side screens, which the filmmakers ideally produce at the same time as the shooting. The content must then be adapted to the look of the main image in post-production and delivered together with it (also encrypted). The films from which ScreenX variants were made include "Captain Marvel", "Shazam!" And currently "Pokémon Detective Pikachu".

HDR initiative

Current developments show that Hollywood not only wants to create an HDR standard for the cinema, but also has its eye on the screens. DCI, behind which Disney, Paramount, Sony Pictures, Universal and Warner stands, published two drafts in parallel in November 2018: one to expand the digital cinema specification to include HDR and one for HDR on cinema screens (called here "Direct View Displays" ).

This coupling played into the cards of industry representatives, who argue that only LED screens have the necessary combination of brightness and contrast to be called HDR-compatible. When projecting, even with a double laser, they speak at best of an enhanced contrast range (enhanced dynamic range, EDR).

After the projector manufacturer expressed displeasure with this approach, the DCI followed up with a statement at the end of March in which it emphasized that a new version of the digital film copies (Digital Cinema Package, DCP) with HDR information was not only available on screens, but also would target HDR-capable projection systems.

Hollywood's desire for an HDR standard is understandable: no studio should want to produce different versions for all possible playback systems. It is fitting that Samsung is emphatically open to Onyx when it comes to the HDR format, although the company has developed HDR10 + as a format to compete with Dolby Vision for home cinema.

Conclusion

All in all, the newer developments around video streaming and home theater technology are obviously also driving innovations in the cinema sector. The cinema-goer can be happy about it: Instead of “shoe box cinemas” there are more and more movie theaters that deserve this name. On the other hand, cinema operators have to recoup the considerable investment in large halls and modern technology. In this respect, it is also exciting to see how the prices for tickets will develop over the coming years - and for drinks, popcorn and the like in the cinema. (nij)

This article first appeared in c't 12/2019.