Sound is 1 frame ahead

[Jose Luis Diaz]

Hi,

I’m having a rare problem with a RED ONE in these days.
This is a shooting at 25fps progresive. This is a TV MiniSerie. TV in Argentina is PAL, not NTSC.
We use a Denecke SB-T connected to the camera.
Everything is OK. RED ONE shows the lock and the chain. Sound recorder is jammed with our Denecke SB-T once per 4 hours. Sound recorder is a brand new Sound Devices 788.
A guide sound is sent to one channel of RED ONE.

But as soon as we sinchronize that image material with sound recorded in Final Cut Pro using "Merge" using TC as link the sound is around one frame a head of the guide track in the camera. I asume that the guide sound is in sync. That no delay can happend.

Why sound is one frame a head?
Do you have a clue?
Have any of you heard about anything like this?

Thanks in advance.

José Luis Díaz

 

[Gunleik Groven]

Quite common...

The signal processing of the image is a bit heavier than that of the audio, thus you get a "fixed" difference... seems to be the explanation.

Gunleik

 

[Jose Luis Diaz]

Oh!
I see. So, nothing I can do except to move +1 frame each sound clip in my ProTools.
Ok. Thanks Gunleik

Edit: Gunleik, there is a way to add an offset of -1 Frame of TC in RED ONE?
I mean, there is a way that RED ONE could record TC with a -1 frame?
Thanks

 

[Marc Wielage]

What I would suggest is that you offset the sound timecode by one frame -- assuming you're talking about a 1-frame offset in a separate sound recording.

If you're talking about a 1-frame offset within the Red itself, don't overlook the possibility that you're seeing a 1-frame offset in your monitor. Many, many LCD and plasma monitors delay the picture about a frame, creating lip-sync issues.

 

[Jose Luis Diaz]

Thanks Marc for your answer.
It is not a delay built by the monitor. The very same sound is fed to camera and to sound recorder. Once synchronized in FCP thanks a procedure called "Merge by TC" shows the sound recorded in Sound Devices 788 one frame ahead of the very same sound in the camera. It is not a delay provoked by the monitor. You can see the delay in Time Line. The sound that is imported with the image is one frame late in comparison with the sound coming from the sound recorder.

 

[Marc Wielage]

In that case, shift the timeline on every take and lock the clips. Problem solved.

There are a few recorders -- the Deva and Fusion are two I can think of -- where you can do a timecode offset while recording on the set to avoid this problem. But even on Red projects, I've never had a client ask for it. They just deal with it in post, having the assistant editor slide everything 1 frame (or whatever the offset is).

 

[Jose Luis Diaz]

Ok.
I will ask production sound mixer to research if in Sound Devices 788 it is possible to do a timecode offset of +1 frame.
In case it would not be possible I will move 1 frame later all production sound tracks in ProTools.
Thanks Marc.

 

[paulherrin]

it seems there should be a more reasonable answer to fix this. is it not possible to write a script that could handle that task?

or if i'm reading gunleik's prediction right, could we add an option in redcine-x to offset the timecode on the r3d?