Alternative framerates have never been part of the DCI 'spec'. Just as now you can not guarantee that a specific server is able to do all 25 or 30 or even 48 or 60fps (e.g. Dolby DSS100).

At some point, SMPTE took over, while DCI is basically restricting themselves to 'minimum' recommendations.

I know that there is a group working on even more/stranger framerates for archival/historic purposes (e.g. 16fps oder 18fps).

Fact is - a lot of analog and electronically shot footage is  now 23.97 with 48KHz audio, and a lot of that footage will be source to DVD-O-MATIC conversion in the future.

Those servers with MPEG-2 and h.264 support will usually also offer 23.97/23.98 support.

I admit it would not be safe to recommend a 1:1 23.97 conversion just because it is possible with DVD-O-MATIC, but that's no reason not to include it, as has been done with other frame rates.

I just don't like unneccessary conversions ;-)

Maybe Wolfgang has better references?

- Carsten

P.S. - I just looked up the datasheet for our Sony SRX-R515 - it quotes 29.97fps for DCI content, but not 23.97/23.98 . However, 23.98 is of course supported over HDMI. 

Christie projectors support 23.98 over HD-SDI per spec, as do some Doremi servers. 

Hmm...do we want dvd-o-matic to have/enable experimental features? ;-)