Friday 24 August 2012

About DCPs and digital cinema

A friend asked me about showing his movie (can't call them 'films' anymore) at a film festival. And the festival asked him for a 'DCP' and something about JPEG-2000 or MPEG-2. This friend and many others, are used to showing their movies at informal gatherings, as DVDs, sometimes even Blu-ray disks, or, showing a movie file off a standalone player like the WD player. Some even connect their laptop to a TV or small projector, and show it.

The WD player is an amazing device. It enables you to connect a hard drive or even pen drive and play a variety of movie files. AVI, MPG, VOB, MKV, MOV, WMV, nearly any type of file can be played off it. And you can connect the WD Player to any HD TV set or projector. It even works with Mac formatted disks. Actually I think every festival and public theatre should have a WD Player, or permit their projector and sound system to be hooked to one.

To return to 'DCP'. This stands for Digital Cinema Package. It's a file format, or rather a bunch of folders with files, which can be read by a device called 'Digital Cinema Server'. Which is a computer with some special software that can play DCPs. Most multiplexes in Mumbai and other Indian cities have one. Connected to a high resolution projector.

The compression used in making a DCP is usually JPEG-2000. And file format is MXF. Picture is compressed, while sound is not. Wikipedia has a complete technical explanation here...

Without going into a detailed technical explanation about DCPs, I'll touch upon how they are made.

There is usually some software on a PC based system that takes DPX or TIFF files for picture and WAV files for audio, and 'encodes' (nerd word for convert) them to a DCP. These can then be encrypted and locked with a 'key'. The key ensures that the file can only be played at a specific location and on a specific range of dates. So that's a kind of a anti-piracy mechanism.

So where do you get a DCP made?

In Mumbai, Reliance Media Works, Real Image, UFO, Scrabble, and some others make these. But they all need DPX or TIF files as picture, and WAV files as audio. If your movie has subtitles, you can 'burn' these in to the picture. Or, provide them with an ASC file which contains subtitles in a special text format. So these are switchable subtitles. You can also provide subtitles in multiple languages and the theatre where the movie is to be shown can switch the language at will.

What if, like most independent movie makers, you have an output off FCP or Avid. In the form of an Apple ProRes or DV, MOV file? When then you're out of luck. Most of these DCP creation places cannot read anything except DPX or TIF. So you need to convert your MOV file to DPX or TIF first.

I've done these conversions for many of my friends and many have been successfully shown in theatres.

There are even software packages that let you make your own DCP. Even with a key. Qube, Quvis, Fraunhofer and others make such software. I'm thinking of investing in some such software but watching and waiting to see how the demand grows (or not).

But what if you don't want to go through the trouble of making a DCP and you're happy showing it off a WD player? Well then go with it. Most theatres that have a Digital projector have one with either a DVI or HDMI input. You can connect the WD Player to the projector with the appropriate cables.

Sound may be a bit of a problem though. If your sound is stereo, then the theatre sound system will accept a stereo input with the appropriate cables. Theatres usually have such a sound system to play music before the movie begins. If your sound is Dolby 5.1, then the theatre's Dolby processor may or may not have compatible inputs for a WD Player. Though a Dolby processor will have six separate analog inputs. In that case you'll need more than cables, you need a decoder to convert the WD Player's digital output to six analog outputs.

Some months ago I showed a full 3 hour feature at the Cinemax theatre playing Apple ProRes files off my laptop who's video display output was connected to the theatre's projector. And sound system connected to the stereo output of the laptop. At the Pixion theatre (where i used to work, not any more, though) we had a permanently connected MacPro from one of the edit suites to a digital projector. And the six track output to the theatre's Dolby system. So we showed many a movie here off FCP with full Dolby surround. Sadly, the Pixion theatre is no longer operational, I believe.

Lastly, a Blu-ray disks also not a bad choice. They are reasonably easy to make, full HD in resolution, and carry up to 8 tracks of audio for full surround. And you can add subtitles which can be switched or or off as needed.

So these are the choices one has, for showing one's movie or short film at a less endowed film festival or theatre, or if one has a budget that does not permit making a print or a DCP.