Hi everyone,

I'm about to edit a film that will be shot using a Sony EX3, recording at 23.976fps, in progressive mode "24P". Sound will be recorded separately on an Aaton Cantar.

It seems like any normal NTSC production, but as I live in PAL land, this is all a bit confusing...

Let's start with the shoot questions:

- What TC should be used on the sound recorder? 29.97 or 23.976?

- Also, we'd like to link the TC of the camera with the TC of the Cantar to speed up the synching process: can I use 23.976TC for this? Or use 29.97 on the Cantar and record it as audio on track2 of the camera?

- I now understand after much reading that 48048Hz should only be used with material shot at 24fps and post-produced at 23.976. Am I correct?

Any other advice welcome!

Take a look at www.24p.com and www.zerocut.com.  The first is written by Michael Phillips, Avid Technology 
film guru and the second is written by Alan Stewart, former Avid employee and current film editor.  Both resources are
excellent. 

pierreh:

- What TC should be used on the sound recorder? 29.97 or 23.976?

You can use either one. You can have sound record with 29.97 or 23.976 TC (if the Cantar - and firmware version - support it). 

pierreh:

- Also, we'd like to link the TC of the camera with the TC of the Cantar to speed up the synching process: can I use 23.976TC for this? Or use 29.97 on the Cantar and record it as audio on track2 of the camera?

If you can have everyone on the same 23.976 TC, I would do it. It just makes sense in this day and age. You just need to make sure the Cantar (with whatever firmware he's using) can record at 23.976 TC, and if your production is using smart slates that the slates he's using also support it 23.976 TC. I tried to do an all 23.976 TC workflow a few jobs ago and the smart slates are what killed the idea - the slates my mixer had wouldn't do it. 

Looking at the specs for the EX3 it looks like it has a BNC in for TC and XLRs in for Audio. So, technically it's possible to pipe it either TC or Audio. The considerations for this are that you may need to tether the camera to the sound recordists cart with a cable in order to pipe the TC / Audio. If your recordist has wireless transmitter gear to send the TC / Audio wirelessly, and the camera guys don't mind adding a receiver box on the camera (added weight) then you could also send TC / Audio wirelessly.

Another consideration is how are you going to be synching? In telecine/transfer? In the Avid? Both? Neither? Are you hoping to bypass a traditional telecine bay and just load your masters directly into the Avid? Will there be anyone on your show (producers, the director) who will want to see DVD dubbs or dailies with sound? If so, you need to think about how that element and that sync will be done.  If you can pipe your sound recordists mix track(s) to the camera (either with a cable or wirelessly) then your original camera masters will be sunk. You could use these to generate dubbs for screening purposes. If, for whatever reason, you can't pipe sound to the camera and you have people who need to see sunk dailies then you need to figure out how and at what stage you're going to do that. If you're going to be synching in the Avid using the original BWF audio then having both the camera and the Cantar sharing the same TC is going to be key - you can autosync via StartTC and you're off to the races.

Note: One additional note about using the Cantar and synching in the Avid. If you want to use Polyphonic BWF files, you may want to ask your recordist to "PolyRotate" his tracks. The Cantar normally records the mix tracks on channels 7+8. Channels 1-6 are used for the isolated mics. For editorial this can be problematic, so Aaton developed a process called Polyrotation. This will re-arrange the channels so the mix tracks are on channels 1+2 and the isos are on channels 3-8.

pierreh:

- I now understand after much reading that 48048Hz should only be used with material shot at 24fps and post-produced at 23.976. Am I correct?

Yes. If you're shooting HD, rolling @ 23.976, you're already running at "video speed." The sample rate for 23.976 digital videotape is full-rate 48.000 kHz.

48.048 would only be used if you're shooting 24fps film which would then get pulled down in telecine to 23.976. During that process you would also pull your audio down to 48.000 for xfer to digital videotape.