24fps or 25fps?

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It’s a common dilemma in the UK for filmmakers: do you shoot at 24 or 25 frames per second? Until a couple of years ago, I would have said 25 every time, but with DCPs and Blu-rays now about, and most TVs capable of handling a range of frame rates, the answer is not so clear-cut. Unlike aspect ratio or shooting format, the decision has no discernible creative impact on your project, merely a technical one. And it’s so easy to convert between the two that it often feels like it makes no odds. Nonetheless, to help anyone on the horns on this dilemma, here’s my round-up of the respective advantages of each frame rate.

The Case for 25fps

  • If you need to record to any kind of tape format at any point in your process, 25fps is what you need.
  • The same goes for PAL DVDs.
  • If your film is going to be broadcast on UK TV, it will be transmitted at 25fps.
  • Since your camera’s running in sync with the UK mains supply’s alternating current, you don’t need flicker-free ballasts for your HMIs. Having said that, pretty much every time I’ve hired an HMI, it’s come with a flicker-free ballast as standard anyway.
  • If you’ve made a 25fps feature film that isn’t quite long enough for distributors to classify it as a feature, the extra running time you squeeze from exhibiting it at 24fps might make the difference.

The Case for 24fps

  • For maximum compatibility, Digital Cinema Packages should be authored at 24fps.
  • The same goes for Blu-rays. (Blu-rays do not technically support 25P, but they support 50i, which can contain progressive 25fps content. However, discs authored to the 50i spec apparently will not play on most US machines.)
  • If you shoot at 24fps and need to convert to 25fps for any reason, your film will become 4% shorter, making it that extra bit pacier and able to squeeze into a shorter slot at a film festival.
  • If shooting on film, your postproduction facilities will be much more comfortable with 24fps material. We really freaked out our lab on The Dark Side of the Earth by shooting 25.
  • Many traditional film projectors will only run at 24fps.

Can you think of any other factors that I’ve missed?

I’d say the balance has tipped in favour of 24fps. However, I think you’ll find that many people in the UK (outside of the celluloid world) are still more comfortable with 25‚Ķ. for now.

24fps or 25fps?

Stop/Eject Cast and Crew Screening

Me, Georgina Sherrington, Amelia Edwards, Therese Collins and Oliver Park at the screening
Me, Georgina Sherrington, Amelia Edwards, Therese Collins and Oliver Park at the screening. Photo: Denis Baudin

Last weekend Stop/Eject, two years in the making, got its first proper screening at the Mac in Birmingham, to an invited audience of cast, crew and sponsors.

The film had been in postproduction for fifteen months – as long as my feature Soul Searcher. With every film I make I want the quality to improve, which means more time, and I want to do fewer jobs myself and turn them over to talented specialists, which again means more time because they’re all fitting it in as a favour around paying work.

The DVDs and Blu-rays arrived in the nick of time.
The DVDs and Blu-rays arrived in the nick of time.

So it might have taken a while, but it was worth it, and it seems that everyone who came along on Saturday agreed. Those of you cast/crew/sponsors who have a Blu-ray copy will be able to see the huge difference wrought by editor Miguel Ferros versus my original cut.

But even since picture lock back in January the film has come on leaps and bounds. The actors were all convinced that the edit had changed since they saw it at the ADR session, but actually all that had changed was the soundtrack. Henning Knoepfel’s sound design and Scott Benzie’s beautiful music, both delicately mixed by Jose Pereira, bring a whole new dimension to the film. Again, if you have the DVD or Blu-ray, be sure to check out the Superior Sound Reproduction featurette for a glimpse into the transformative process of postproduction audio.

Georgina Sherrington. Photo: Paul Bednall www.paulbednallphotography.co.uk
Georgina Sherrington. Photo: Paul Bednall www.paulbednallphotography.co.uk

The day itself was really nice, with most of the key people attending and everyone having a good time. After the screening many of us went on to Fletcher’s Bar and Restaurant to drink, chat and gather around a TV to watch Record & Play: The Making of Stop/Eject.

As usual with these events there is a tinge of sadness. Will I ever see some of these lovely people again? Will we get to work together in the future? With all the good will going round at a premiere, you want to start shooting a new film with the same team the next day, but of course it never works out that way.

Anyway, thanks once again to everyone who came and everyone who supported Stop/Eject. Venice Film Festival has already turned down the film, but there are plenty more to enter and you’ll all get to see it eventually on the festival circuit or (ultimately) online.

Stop/Eject Cast and Crew Screening

Making a Digital Cinema Package

The finished Stop/Eject DCP. Not as cool as a roll of 35mm.
The finished Stop/Eject DCP. Not as cool as a roll of 35mm.

Now that huge reels of 35mm film are all but obsolete, Digital Cinema Packages (DCPs) are the new means of getting a film to a cinema. Many top film festivals will only screen off a DCP or 35mm print, and in terms of picture and sound quality and compatibility it is your best option for screening at theatrical venues in general. Much has been written about how you can make a DCP at home for nothing, but having just gone through the process myself for Stop/Eject I’m going to round up some of the best sources of information I came across and enlarge on the area of disc formatting which hasn’t been too well covered elsewhere.

To ensure maximum compatibility of your DCP you need to:

  • convert your film to 24fps if it isn’t already at that frame rate
  • use a standard 2K aspect ratio, 2048×1080 or 2048×858
  • put it on a disc that is EXT3 formatted
  • supply that disc in a Cru Dataport DX-115

I’ve spoken to filmmakers who have ignored many or all of the above and still run their DCPs successfully in cinemas, but I decided to play it safe and do all of the above, except the Cru Dataport, which was a little too expensive. Instead I bought a 500GB LaCie Rugged USB drive and put my DCP on there. Read Knut Erik Evensen’s excellent blog post on DCP delivery for more info on Dataports and USB compatibility.

The formatted drive as seen in Ubuntu, with the DCP files copied over
Step 5: the formatted drive as seen in Ubuntu, with the DCP files copied over

So, here is the process I went through. I was starting out with 25,409 uncompressed 16-bit TIFF files representing each individual frame of Stop/Eject, and six mono 24-bit linear PCM WAV files for the 5.1 surround soundtrack. The TIFFs were in 1080P (1920×1080) letterboxed to an aspect ratio of 2.35:1.

  1. First of all I used Photoshop to batch convert all the TIFFs to the 2048×858 aspect ratio. This is actually 2.39:1 rather than the 2.35:1, so it meant cropping a sliver of the actual picture off the top and bottom, not just the black bars, as well as enlarging the picture slightly. It took my poor iMac about 12 hours to convert the 25,409 frames. I’m sure there’s quicker batch conversion software out there than Photoshop if you hunt around though.
  2. Next I used a free piece of audio software called Audacity to slow down each of the six audio files by 4% so that they will match the images when they run at 24fps. (Stop/Eject was shot and edited at 25fps.) Thanks to Matt Cameron’s blog for this tip.
  3. Then I downloaded and ran OpenDCP, the brilliant free software that actually creates the Digital Cinema Package for you. It’s very simple to use, but check out the help Wiki and Danny Lacey’s seminal blog post to guide you through it. The end result was six files: four XML files and two MXF files, one for sound and one for picture. Encoding at the default bitrate of 125mb/s, which the Wiki says is more than good enough for 2K at 24fps, Stop/Eject’s DCP was just under 17GB, so about 1GB per minute.
  4. Now the tricky bit – copying those six files onto an EXT3 formatted drive. EXT3 is a Linux file system, and is not supported by MacOS. So I downloaded Ubuntu, a free operating system which does support it. (Choose the 64-bit download unless you have quite an old computer.) The downloaded file is a disc image (.ISO) which you can burn to DVD using Disk Utlity (found in the utilities sub-folder of MacOS’s Applications folder). Then restart your Mac, with the DVD still in the drive, and hold down C when you hear the chimes. This will boot up your Mac in the Ubuntu operating system. (You can release C when you see the black screen and Ubuntu logo.)
  5. Once Ubuntu was running, I right-clicked the LaCie Rugged in the list of drives in the lower left of the desktop and chose format from the contextual menu. To get more than the default options, I clicked Disk Utility in the dialogue box that came up. I could now select EXT3 as the file system (leaving the other settings at their default values). When I clicked format, Ubuntu didn’t seem to be doing anything, but after a few minutes the Disk Utility showed that the volume had been created. I could then close the Disk Utility, and drag and drop the six DCP files from another hard drive (MacOS formatted) onto my newly EXT3 formatted LaCie. Apparently you can put these files inside a folder if you want, but again to be extra safe I put them in the root directory.

After completing the DCP I took it to the Courtyard, my local arts centre, where head projectionist Simon Nicholls was kind enough to let me test it. To my very pleasant surprise it worked perfectly, uploading at about real time via the Doremi server’s USB 2 socket and playing shortly afterwards with superb sound and picture quality. Much as I love celluloid, the ease and cheapness of this process are breathtaking, the purchase of the hard drive being the only cost. I’ll let you know how I get on running it at other cinemas.

Making a Digital Cinema Package

2012: The Year that Film Died

Dark Side camera negative lab rolls
Dark Side camera negative lab rolls

A couple of weeks ago I screened the 35mm print of The Dark Side of the Earth‘s pilot at the last FilmWorks¬†session in Bristol. It had been about 18 months since I last ran the print, and I was shocked how much attitudes towards celluloid had changed in that time. People were acting like they hadn’t seen a roll of film in 20 years, like I was some kind of whacked-out nostalgia hippy for wanting to shoot on 35mm. (But it still looked fucking awesome on the big screen.)

Digital cinema is one of those things that’s been lurking on the horizon for ages, then suddenly, silently… it’s here, like it’s always been here. Projection of moving images from celluloid is very, very quickly becoming extinct, as is acquisition of moving images on celluloid. Suddenly the likes of Christopher Nolan and Quentin Tarantino, staunch defenders of shooting films on film, are starting to look a bit loony, although I agree with them completely.

In September Fuji announced it would cease manufacturing of film stock, leaving only Kodak in the “market”, if such a word can be applied to an unwitting monopoly.

Dark Side mute print
Dark Side mute print

So we’re quickly heading towards a world in which “film” is a word completely divorced from its original meaning. Plastic strips coated in light sensitive emulsion will no longer play any part in the production or consumption of “films”.

The other day I went to see The Hobbit: An Unexpected Journey. Although I chose to see a 2D 24fps screening, Peter Jackon’s sedate trilogy has been made in 3D at 48fps. The higher frame rate produces smoother motion which most people will associate with news broadcasts and documentaries. Overall the aim seems to be to make watching a film more like experiencing real life – sharper, smoother, three-dimensional. But is that what we really go to the cinema for?

It’s not what I go for. I want the scratches and the weave and the flicker because without them there is no magic, there is no suspension of disbelief. I want escapism. I want film. It seems I’m to be disappointed for the rest of my life.

2012: The Year that Film Died