Recording audio at 24 or 25 fps
 

I've been working with an Edirol R-44 mostly on short films during the last months. A few weeks ago I shoot a commercial, and after a few days the producer came back to me and asked If I had recorded the audio at 24 or 25 frames per second.

Honestly I didn't know what to answer because the R-44 has no time code capabilities.

Now the question is:

Is this a setting that really affects the sync between picture and sound? If so, how can I know if my R-44 records at 24 or 25 fps?

All your help will be greatly appreciated!!

Regards,


Andres.

Your producer's question is nonsense. There is no such thing as a frame rate for audio. With timecode the frame numbers correspond to the image frame rate but without TC frames just don't exist. 1 second of audio is 1 second of audio regardless of how fast the camera in the room was shooting pictures.

I agree with Steve, but why did the producer want to know exactly that?

Was their any actual film involved in your production or was it all completely on digital tape?.

Cheers.

Ditto again for the above.

Might as well let your producer know that you can do complimentary frame rate conversions on the audio at no extra charge for anything you are requested to record. Make yourself as useful as possible. :-P

Andrew

It was shoot on the Red One. Would it be different if it had been shoot on film??


Thanks.

Not without timecode that's associated with the audio.

Very possible the producer assumes the audio is being recorded with timecode synched to the video... timecode that is generated by the Indi-sphere.

What kind of clapboard and slate are you using?

Hi Jack,

what exactly do you mean by Indi-sphere?

We were using a simple clapperboard, nothing digital involved, and no connections between camera and recorder.


I'm also confused because of other job I did for a film school. There I worked with the Nagara V. We had no TimeCode connection between the camera (35 mm) and the Nagara, but they asked me to record the audio at 24 fps. I changed the setting to 24 fps but I think what it actually does is to define the format of TimeCode the Nagara will be receiving from an external source; is that correct?

Thank you all for you answers.

Regards,

Andres.

The digital audio equivalent to frames per second is the sample rate, with the video standard being 48kHz. One second of audio contains 48,000 samples no matter what speed the camera is running or what the timecode, if present, reads and 48,000 samples of audio will play back in one second. When timecode is used, it provides a cross-reference so you can know that "this" sample of audio was recorded during the same period of time that "that" frame of video was being recorded - that's all. Timecode settings on the recorder, when present, have no impact whatever on the speed that the audio is recorded or will be played back. Back in the analog days, when old-fashioned magnetic tape was used and a track of linear timecode was recorded on tape alongside the audio, the recorded code actually controlled the speed of the "resolver" that bounced the audio from the 1/4 tape master to magnetic perf film for editing. But that dissappeared along with the passing of editing on a Moviola or Steenbeck and manually cutting and splicing negative. Unfortunately some producers and others who should know better haven't yet got the word. I'll repeat, there is no such thing as a frame of audio, hence no such thing as frame rate for recorded audio, and the timecode setting or lack of it has no effect on playback speed what so ever.

Thanks Steve,

that is a great explanation, and it makes this point clear... now all I need to do is explain this to the producers :)

While talking about this with an editor, I found that another reason why they ask this, is because when they import audio files in Avid they are prompted to select a TimeCode format. I guess that as Steve explained, that is just for positional reference.

Thank you all for the help!!!

Andres.

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