25fps v 24fps

Anything and everything to do with DCP-o-matic.
rtX
Posts: 83
Joined: Tue Apr 22, 2014 6:08 pm

25fps v 24fps

Post by rtX »

Not a dcp-o-matic problem, but I just thought I'd share an issue I encountered today. I took my DCP which was mastered/shot at 25fps to a well-known screening facility in London. Two of their three screens were unable to play a 25fps DCP. They can only play 24fps and a few other frame rates. I was told that only 1 in 100 films are at 25fps and that although a DCI standard, I'd always encounter issues if I continued to use a 25fps version especially in the UK and the USA. As it happens, I'd had the sound re-pitched to 24fps anyway as I was planning to make a 24fps master for the USA anyway (needed for NTSC conversions), and so now I'm making a 24fps DCP version of the film, too even though it will be 4% longer.

As many cameras can shoot at 24 and 25, it might be worth shooting at 24 to avoid this hassle.
Carsten
Posts: 2804
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: 25fps v 24fps

Post by Carsten »

There are a lot of 25fps DCPs distributed nowadays. There are two different issues - one is, that officially, 25fps is only supported in SMPTE packaging, not Interop. Yet there are a lot of servers around that support 25fps in Interop as well.

Now, there are some old servers around that do not support 25fps J2k DCPs at all, not in Interop, not in SMPTE packaging. Dolbys DSS100/DSP100 is the most prominent, and that is still used a lot world wide.

So, yes, if you do not know exactly which servers your content will be played on, choose 24fps. DCP-o-matic has no trouble to create a 24fps DCP from 25fps footage.

For some releases, mastering facilities create both a 24 and 25 fps DCP.

- Carsten
amiga78
Posts: 15
Joined: Tue Apr 15, 2014 4:07 pm

Re: 25fps v 24fps

Post by amiga78 »

I'm reading that "a SMPTE DCP with 25/30 fps and a 24 fps interop backup is the safest way" -for delivering to cinemas at the moment.

And I'm trying to get my head arround this "ISDCF Mixed Distribution Package". Does that mean delivering a SMPTE and Interop DCP in the same folder since these two formats seam to share the same .xmf files and only the .xlm files differ? Am I correct?

Also since DCP-o-matic can make both SMPTE and Interop and also both 24fps and 25fps would it be possible to render both in one go instead of two separate folders and twice the render time?

I'm just thinking, since the recommended way to deliver a DCP is to deliver two DCPs, would it not be awesome if we could render both at once. 8-)