- In practice
|The basic installation|
It seems that digital cinema will have completely taken over the baton from traditional 35mm projection within two years. In recent years, many cinemas already became familiar with digital projection, but still as many theaters did not. Therefore, many exhibitors still have questions. Actually, a lot of information can be found about this topic - but what is suitable for your situation?
Digital cinema projectors can roughly be divided into 2 types. The first group is based on Texas Instruments' DLP cinema technology. This technology, which was developed in 1987, literally gave birth to digital cinema and has offered the possibility to project in 2K (2048 x 1080 pixels) resolution since 2004. From early 2010 on, the 2nd generation of this 2K technology has been supplied under the name of series 2.
DLP cinema technology forms the basis for all digital cinema projectors from Christie, Barco and NEC (including the brands Cinemeccanica and Kinoton that use Barco technology). The projection part of all these brands is similar in many details. However, components are not interchangeable. The various brands differ in the following issues:
All DLP cinema projectors in the market will be presented later in this chapter.
Secondly, there is the projector from Sony based on their SXRD technology. These projectors have been on the market for some 5 years and offer the possibility to project in 4K resolution (4096 x 2156 pixels). Since the end of 2009, the SRX-R320 projector has been on the market which comprises the most recent technology, similar to series 2 DLP cinema projectors.
In the meantime, Texas Instruments have also been busy; since early 2011, 4K DLP cinema projectors are also available. In addition, the projector manufacturers announced that certain 2K projectors can be 'upgraded' to 4K resolution.
The projector: 2K vs. 4K?
It is obvious that the choice of a projector may quickly lead to favouring 4K technology, but is this really necessary and does it make sense? The answer to these questions (beyond all marketing stories) is often no. However, the choice of 4K has to be given serious thought.
Let us first keep to 2D projection. To be able to see the quality difference between 2K and 4K, one does not only require a 4K projector but also a 4K film. Unfortunately, these are still not available very often these days. From time to time films are released in 4K (Karate Kid, Salt, The Dark Knight Rises etc.) but with the increase in 4K projectors, this number will certainly grow in the coming years. If 2K content is played on a 4K projector, this content will be upscaled to 4K resolution. Obviously, manufacturers indicate that this greatly improves the image quality compared to 2K, but the bottom line is that it remains a computer that complements the missing information according to its software; in fact, it therefore remains a 2K image.
When comparing 2K and 4K projection, one may notice that the details of 4K are much better. However, the further we go away from the picture, the less the difference will be noticeable. Visitors in the back of the auditorium (which usually has the best seats), will see the difference much less than visitors in the front. What's more, in a normal situation a visitor cannot compare anything; during the screenings, there is no switch between 2K and 4K projectors. Compare it to digital photography. To get a good 10x15 print-out, a 4 megapixel photo file is sufficient. If we want to print this picture in poster size, then we require a much higher resolution. However, if we look at an enlarged picture from a considerable distance, then the result is okay again. Resolution, screen size and viewing distance are closely related to each other in this context.
In addition, it is also the question of how delivery of digital content will develop in the future. Currently, there are significant differences between the different films (caused by codecs and compression techniques used). The quality of the final presentation is of course closely related to this.
In many cases, exhibitors have an unfounded fear that the future will only bring 4K. This fear is unjustified. Compare the quality of 2K to that of 35 mm; for the visitor it is the same and often the quality of 2K projection is better. As far as content delivery is concerned, because of the file format used by digital cinema it is also ensured that a film can always be played out in 2K and 4K, without requiring a separate disk or file. It certainly is a good effort that manufacturers continue improving their technology and that cinemas watch out to have the latest technology in their theatre.
3D and 4K projection
If a Sony projector is used for 3D projection, it no longer projects in 4K resolution. The way these projectors handle 3D makes it impossible to maintain 4K resolution. The Sony projector is the only one that uses a double lens and splits up the imaging chip in two, in order to generate 2 separate images (separately for the left and right eye). Despite the reduced resolution, this technology provides an amazing 3D image.
It is also possible to screen 2D films in this way, to avoid having to change the lenses each time (see also the section about the Sony SRX-R320 projector). In this case, both for 3D and 2D projection the resolution is 1998x1080 pixels for widescreen and 2580x1080 for CinemaScope. In case one anticipates that a projector will many 3D films, this issue must be considered when taking a decision.
There is not much to say about 4K DLP cinema projectors and 3D. It seems that all existing 3D systems can still be used and that 3D projection in 4K will be possible in the future. However, it will mainly depend on the studios and the servers whether it will be worthwhile to release 3D content in 4K from a technical point of view. 4K in 2D involves a huge data transfer, and 4K in 3D will involve even more.
4K projection and the server
To be able to project 4K images requires more than just alterations to the projector. The amount of data that has to be processed for 4K is 4 times as large as for 2K projection. This is impossible via the traditional video transfer link (2x HDSDI 292 SMPTE). Therefore most server manufacturers now opt for an Integrated Media Block (IMB). As a result, the video board is no longer placed in the server but directly in the projector, which entails a shorter video data transfer. In this way, it is not only much easier to build up a connection with a much larger bandwidth, but transport is also much safer as the enclosing projector forms a safe environment. However, the storage of the content then takes place on a (in this case, stripped-down) server. Between the server and the media block there is a PCI-E connection, or in some cases ethernet, which allows transporting the secured data to the IMB more easily.
Now, as the upgrade to 4K has become reality with TI systems, it may be assumed that the server as we know it today has had its day, and that the IMB principle is the future in both 2K and 4K. Following Doremi and GDC, Dolby have also presented their IBM recently. Sony have used a media block since the introduction of their projectors. The media block is fully integrated in the projector and is a part of the secure part of the projector. Although this initially looked very odd, it now seems that all manufacturers will follow this path in the future.
By the way, developments in image quality go further than just increasing the resolution. Currently, studios and film directors are also seriously looking at increasing the frame rate, Peter Jackson's The Hobbit being the first one at the end of 2012. For a while, various servers (e.g. Doremi) have offered the possibility to play out specially processed content at 48 frames per second (fps). Further developments even go up to a speed of 60 fps. The changes to server and projector are minimal while the effects on the projection quality and especially the steadiness of the projected image are huge. Of course, this development requires well adapted content, but due to the simple implementation this may soon become reality.
Below you will find a list of digital cinema projectors that are currently available in the market. Overall, the main features are listed or reference is made to a similar type. Over the last year a number of 4K projectors have been launched onto the market. These are not yet included in this overview.
There is a separate touch screen available that can be mounted on the projector, but you can also opt for a laptop computer on which the (free) Barco Communicator software runs, and which is equal to the touch screen. Via the network, it is possible to access all projectors on a laptop. The projectors use 'special' xenon lamps, which are available from the main brands. Remarkably, Barco only uses 1 adapter for fitting the xenon bulb. The length of the bulb has been adapted to the projector.
The projector has a particularly attractive modular construction which allows changing components quickly in case of fault. Barco is the only one having a lamp module which allows switching the lamp power without having to dismantle the xenon bulb (see also the chapter on xenon bulbs). Moreover, the projectors allow the smoothest integration of Dolby 3D for which no DCF100 controller is required since this functionality is integrated into the software of the projector. All Barco projectors have a very simple way to set the convergence of the projectors.
The xenon bulbs for the B series are similar to those for the C series, obviously with more powerful bulbs in the largest model. The integration of Dolby 3D is the same as for the C series, as is the modular design. The system for an easy adjustment of the convergence - important for the installation - has also been adopted. The 19B is usable up to 3 kW and requires a single-phase 230 volt 20 amp mains connection. The B series projectors have built-in control for the external exhaust.
Christie projectors have a "no-nonsense" construction, both inside and outside. They are characterized by a very high light output and, in addition, are completely operated via a touch screen. Usually, this touch screen is located at the back of the projector, but it can also very easily be installed at any other place required. Depending on the projector type, there are one or more filters. These have to be replaced at certain intervals. All projectors use a liquid cooling system for the internal components.
A special feature of the Christie projectors is the so-called LampLOC function. After installing a xenon bulb, the projector itself shall automatically calibrate the optimal lamp settings (X, Y and Z axis) for a maximum light output. All projectors have 3 status indicators on the back, so that a malfunction of the projector can be seen at a glance.
German company Kinoton offers digital projectors that utilize Barco technology for the projection part. These projectors are equipped with 1.2" series DMDs, similar to the B-series projectors from Barco. The projectors are upgradable to 4K. Unlike Barco's projectors 'normal' xenon bulbs can be used. However, the maximum light output can only be achieved with a special xenon bulb.
The lamp house is a company-owned design and cannot be changed as one module, as it is the case for Barco projectors. An exhauster is integrated into the lamp house. The projector requires a 400 volt 3-phase 16 amp mains connection. The projector is very different from the competition, with its sturdy construction (heavy use of metal, adapted cooling system, etc.).
NEC is the only manufacturer offering 4x HDSDI input as a standard, which can be useful if besides projection via the server, HDCAM or 3D satellite receivers are used for events. This means that no cables need to be replugged. Since the NC3200S is currently the only projector in the series with 1.2" DMD chips, it is the only NEC projector upgradable to 4K.
All projectors use liquid cooling for the internal components (a maintenance-free system) and use several air filters that have to be replaced at regular intervals. Standard xenon bulbs (i.e. types used in 35mm projectors) can easily be used (however, maximum light output is not reached that way). This could be an interesting alternative if the light output is sufficient, for instance if there's no need for 3D projection. The projectors have indicators on the back that allow for checking the projector status at a glance.
CineAlta 4K SRX-R320
The built-in server, the LMT300, which Sony calls Mediablock, is inseparably connected to the assembly. All components of the Sony projector are placed in a housing: the 'cavity'. Contrary to a DLP cinema projector, where the data stream between the projector and server is secured, in this case the entire interior of the projector is secured. Opening the projector breaks this protection, and therefore the ability to play protected content. The projector provides only 1 external video input (DVI-D). This can be expanded: DVI-D and HDSDI interface boards are available.
Operating the projector is done by means of a touch screen on the projector. This does not only allow for operating the projection part, but also most of the functions of the server. There is a simple LCD display on the back of the projector for warnings and error messages. The top of the projector includes a 'traffic light' that indicates the status of the projector by means of different colors and blinker frequencies.
The projector has a motorized zoom lens to screen 4K. However, lens shift is not automated. This may cause problems if the projector is installed in the central axis of the screen and masking has to be used.
A separate lens is required for screening 3D. This lens was developed in conjunction with RealD and is currently the only 3D system available for Sony. If this lens is used, the resolution is no longer 4K but 1998x1080 for flat and 2580x1080 for scope. Exchanging the lens can be done by the projectionist, but it is not a simple job that can be done between two screenings. The whole construction (M10 bolts, thin multicables) is simply not suitable for a quick changeover. It is possible to screen 2D via the 3D lens in a very high quality (but not 4K), so that changing the lens is only required if there are only 2D screenings with 4K content scheduled for a longer period of time.
The server has a storage capacity of 2 TB and features a RAID array of 7 (!) disks, including a 'hot spare' (disk that can automatically take over a faulty disk during operation). The server has several plug-in cards with 16 outputs and 8 inputs. Ingest is possible via the network or via USB 2.0. The user interface (Sony calls this the Screen Management System or SMS) can be seen on the touch screen of the projector or (more in detail) on an external PC or laptop with the (free) Sony software.
The automation has no possibility to use macros, which makes start and pause a little complicated. However, the server can use a show in a show, so that from the start, pause and end of a show separate sub-shows can be made, which can easily be integrated into a show (as if they were macros).
The intermission is worth mentioning, since it has only recently become possible. The Sony projector is the only projector that allows pausing the content and screening other content during the intermission. This allows for instance screening trailers during the intermission. No other server has this option. A show can be started remotely, but external start commands have to be linked to a particular show (thus pressing the start button does not simply start the appropriate show). This makes a remote start or automation rather difficult.
The Sony projector comes with a 1500VA UPS unit and requires next to a normal power supply for UPS (230 volt 16 amp outlet) a single-phase 230 volt 25 amp power supply for the rectifier. The Sony projector is suitable for lamps up to 4.2 kW. For smaller auditoria, 2 and 3 kW xenon bulbs are also available. With a 4.2 kW xenon bulb, the Sony projector is suitable for 3D projection for screen widths up to 15 meters.
Apart from the storage of films, the server is also responsible for the automation and control of the entire auditorium. The interface of the server and its user-friendliness largely account for the user-friendliness of the entire installation.
The DSS200 is the latest generation of Dolby servers. This Linux-based server has a 2.8 TB storage capacity (RAID 5). The server is limited for the user to the possibilities of the interface.
The advantage of the Dolby server lies with the integration of the various auditoria in a cinema. For up to three screens, the servers themselves form a TMS system; this means for instance that the status of the other servers can be seen on each server. Shows and content can also be exchanged easily. If there are more than 3 screens, a DSS100 can be added, which then serves as a TMS / LMS server. The operation of the Dolby DSS200 is very easy and overall feedback about the server is very positive.
Possibilities for automation of the server are a little behind other servers such as the Solo G3 and Doremi. The Dolby server has no macros and therefore cannot compile commands and process them in a controlled way. Especially at the beginning of the screening and during an intermission, this makes the server less flexible and the functions often run a little less flexible. In addition, when programming a show, each command has to be entered separately.
The server has an integrated automation card with 10 outputs. There are also several inputs which each have a fixed function. It is a little bit cumbersome to manage and determine the outputs, as this is done by modifying an XML script. The pulse duration of the contacts is fixed at 500ms. In case a more complex automation is required (more outputs, inputs, other pulse duration, combinations) a Jnior network automation interface can be added. In contrast to the Doremi server, the automation is serially driven. Recently, a new software version has been announced wherein major improvements with regard to automation and control have been included. It will thus be possible to use macros. The exact release date is still unknown.
The Dolby DSS200 (obviously) supports the Dolby 3D system, and also XPAND and MasterImage. To our knowledge, there is no support for RealD yet, as the ghostbusting required for this system is not supported by the server. Ingest of content is possible through the network, USB 2.0, built-in eSATA bay and DVD Player. If an external storage is required, it has to be connected to the server by means of optical fiber. Operation is done via keyboard, mouse and monitor, this may be placed with one of the servers.
The Dolby DSS200 features a 16 channel Digital AES audio output. Thus, a DMA8 plus (or a simpler D / A converter) is required for an analog 6ch input. The user does not have to make many settings on the server. Updates must be enquired with Dolby and are only provided on request (a KDM is required to install the update). The Dolby DSS200 does not have a normal on / off switch or shutdown procedure, as it should remain switched on 24/7.
DCP2000, DP2K4 servers
The possibilities for this server are endless and, in all cases, the automation can be programmed in such a way as to proceed a show smoothly, however challenging this may be. Due to the possibility to include different commands in macros, even complicated combined functions (e.g. screening an intermission image for 20 seconds and the control of light and sound) can be included in 1 simple command. External commands (e.g. fire, etc.) can also be entered as a standard, so that these are applied in every show.
The server has 8 external automation inputs and outputs. In this context, it has to be noted that these cannot simply control everything. There are interfaces available in the market that provide these outputs with relays so that light, curtain, frame, audio, etc. can be controlled safely and easily. The server can also be expanded by means of a Jnior automation interface that has 8 inputs and outputs. That in turn can also be expanded with 4 additional inputs and outputs. In total, the server may provide 20 inputs and outputs to manage external control commands.
Popular 3D systems like RealD and Dolby 3D are supported by the server. In addition, with additional equipment the server offers the possibility to stream content (e.g. satellite) over the network to the server. The reliability of the server is very high. Faulty drives etc. can easily be repaired or replaced by the user himself. The server has 2 power supplies for redundancy purposes.
On the DCP2000, ingesting of content is usually done via USB 2.0 or via a Gigabit network connection. An extension to an external eSATA connection is also possible. The DP2K4 server has a DVD drive, network, USB 2.0 and eSATA bay to ingest content. The server has an AES digital audio output with 16 channels. Doremi provides a simple D / A converter for converting to analog audio. This enables the continued use of older audio processors. In addition to operation with a TMS system, the server can also be easily operated remotely using a free VNC client.
Solo G3 (previously XDC G3; no longer sold)
The advantages of the G3 server lie in the easy to use interface and the possibility to add additional functions to the most common controls. For example: when pressing play, the xenon is always ignited, frames and curtains are controlled, the audio is switched to the correct format, etc. None of these functions needs to be programmed in a show. The same applies to intermission, stop, etc.
In addition, this server also uses so called auto-transitions. This means that the server itself can decide in what format and encoding (MPEG-2, JPEG-2000, 3D) content is to be played-out. The server automatically transmits this to the projector. Consequently, a format change doesn't need to be indicated anywhere in the show. This option, in combination with the simple automation, makes it possible to program a show just by dragging the required advertising, trailers and main movie in the required order and choosing an intermission point.
The Solo G3 has 16 relay outputs and 8 inputs for automation. Ingest is possible via Gigabit network, USB 2.0, external eSATA and an eSATA bay. The server also has a DVD drive and it supports the RealD and Dolby 3D systems. The server comes with a 15" Elo touch screen; mouse and keyboard are not required.
The Solo G3 includes 4 network connections for projector and audio processor (no extra switch required). There is a connection for regular content and a separate connection for external control commands. The server has an AES digital audio output with 8 channels. An extension with channel 9 t / m 16 is possible to allow for Dolby 7.1 reproduction. XDC provided a simple D / A converter allowing a conversion of the audio signal to 6 analogue channels.
Many cinemas in the Netherlands and other countries like to include an intermission in a feature film show. From time to time, installers are therefore asked whether this is possible and whether it is also possible to clearly announce this intermission to the audience.
Since many server manufacturers have their roots in the U.S. and intermission is largely an unknown concept there, most of the systems therefore do not provide this possibility. Consequently, with most of the servers it is not possible to pause the content screened (e.g. the main movie), show a film in the intermission and then continue with the main movie. This does not mean that it is not possible to (temporarily) pause the play-out, which can be done in most cases, but it is not possible to 'squeeze in' other content.
However, TI projectors offer the possibility of a 'trick', as test patterns can be stored in the projector. That way it's also possible to add an intermission picture. During the break, the server retrieves this picture in the projector and the audience gets the message 'lntermission!'. How easy and flexible this is depends on the server. As previously mentioned, Doremi and the G3 are especially strong in automation and this intermission point can be set at will. A Dolby server can also do this, but how easily this can be done depends on the projector used.
The Sony projector is a special case. The media block in this projector can pause the show and during this intermission any kind of content can be played out. This may be a simple intermission image or a separate show with trailers. After a set time (or earlier if the command is given before), the show continues with the original content.
|Last Updated on Wednesday, 19 December 2012 15:45|