Cinema to go Digital

It’s time to say goodbye to celluloid. Major blockbusters like Revenge of the Sith and Farenheit 9/11 have already been shot in digital and transferred to film for cinematic showing. As reported by the BBC, Hollywood studios are backing a new digital standard right through to the cinema screen, after making a deal on how digital projectors should be standardised. Digital Cinema Initiatives, a joint venture between most of the majors : Disney, Fox, MGM, Paramount, Sony Pictures Entertainment, Universal and Warner Bros. Studios, released their final version of the specification on the 27th of July.

The specification

There are two levels of quality dubbed 2K and 4K : smaller cinemas with lower budgets may not have a 4K projector to begin with, but then some films may only be released at the 2K standard since the 4K standard would likely have much higher production costs. No doubt a lot of celluloid to digital transfers will happen initially before directors all make the switch to filming direct to digital.

2K means 2048 x 1080 JPEG 2000 @ 24 or 48 FPS (but at the same maximum bitrate) with 12 bits per subpixel for a total of 36 bpp. 4K is the same except the resolution is 4 times better : 4096 x 2160 and can only be encoded at 24 FPS. The standard provides for 16 channel uncompressed audio, 24 bits per sample at 48 or 96kHz. Subtitles use PNG images and an XML reference file for timing information.

These image sizes equate to a minimum 2.2 megapixel (2K) and 8.8 megapixel (4K) camera format respectively. The aspect ratio is 1.896:1, so widescreen presentations like the aforementioned Star Wars film, at 2.35:1, would in fact be projected at 4096 x 1743. At the theatre, they will need 1TB of storage per screen, as a film will be about 300GB and they need to be able to store a minimum of three full movies. The equipment will be required to sustain 307Mb/s and therefore have at least gigabit networking. Basically the bitrate will be around 250-300Mb/s.

What does this all mean?

Theatres will be able to receive “media” directly over an encrypted high speed network, and store it for showing during the film run. This will make for easy widespread releases of films into theatres across the world with little physical transport costs. The only cost will be bandwidth, but given the size of files they’ll be transmitting – and securely – the infrastructure will not be cheap to begin with. Or else they’ll have to send large hard drives to the theatres but their size will of course reduce transport costs compared to reels and reels of film.

There are a lot of security features in the standard which make it difficult or impossible for cinema staff to downsample the format to a DVD format for example. However, when the studios come to release to DVD, the quality should be at least as good if not better than film conversion is currently as the source itself is digital. Since they’ll be using a digital format for cinematic showing, the DVD conversion process should be easier to manage and therefore cheaper. No doubt DVDs themselves won’t come down in price.

Quality of the projected image may not match a perfect reel of high quality 35mm film, but there will be no degradation over time. It would seem that the key aim of the standard is to ensure a level of quality for image and sound in all theatres, and to allow the cinema experience to outclass all but the best theatres with the best prints in all theatres which meet the standard.

I’m really looking forward to seeing a cinema with this setup, the quality is likely to be superb. I’m going to miss film grain though. Just as digital photography (and especially digital photo manipulation) has led to a world of unreal images and a perfection in certain shots which is too pure, cinema too will follow and lose that grainy, imperfect quality. If you prefer vinyl over CD for similar reasons, today is a day to lament the passing of celluloid.


  1. So the 2K spec doesn’t include 30fps? Why would they do that when HDTV can so easily? Will the studios actually make action movies at 48fps instead? 24fps is too slow and I’m disappointed that 4K won’t do it. The extra detail will be useless when a simple camera pan or tracking shot blurs everything.

  2. Simon

    4/8/2005 at 11:36 pm

    I’m assuming that since regular celluloid film is all at 24fps today, the standard seeks to stay in line with that. Also, with 48 and 96kHz that makes precisely 2,000 and 4,000 samples per frame respectively. It’s also a question of bandwidth no doubt.

    I think that fast action movies may look better at 48fps but 4K@24fps for low movement frames will look pretty damn nice.

    I’m with you on the 30FPS though, although I’d be most interested to find out more about high def movie material that was actually shot at that framerate. Revenge of the Sith was shot at what appears to be the 2K standard, and the level of detail was pretty reasonable.