Sync issues in varicam 24p….DVD RAM audio sources

[Chris Bell]

A sound mixer friend sent me the following response to your post. He is not registered here, so I am posting on his behalf. Hope this helps.

“I would say that it sounds like a pullup or pulldown issue. He doesn’t
mention which way the drift is going. He should post the actual TC and
sample rate specs the sound recordist used to record the tracks. He should
mention what NLE app he’s using. Sounds to me like he’s just trying to input
BWF files straight into FCP which will bring in the audio but not the TC
metadata. He needs to convert the BWF files to Quicktime files using Sebsky
tools and then he will have his timecode as well.”

[Josh Drisko]

Great! thank you. here’s what I know…..the audio drifts behind the video – you see someone speak, then hear them, so that must mean the audio isn’t being pulled down right? I was told told the sound guy recorded at whatever the DP did, that would be 24fps, or 23.98 I guess. But he’s the one who said we could just drag the audio files straight from the DVD RAM into FCP. And that’s what I’m editing in by the way, the latest FCP. I looked at the specs of the files in FCP and they’re 48k, 24-bit. TC says source but they all just start at 00:00:00:00. After reading your post I looked at the source clips and sure enough they’re WAVE files with iTunes icons. I guess I need to do the Sebsky conversion you mentioned. Is that a free software that I cn download? will doing that conversion fix the drifting as well as the TC? this is great help, i’m just now entering the vaicam, HD world so the more I can learn the better.

I’ll start looking for Sebsky in the meantime.

thanks!

j

j-dog edits
jwalkerdrisko@mac.com

[Josh Drisko]

I’ve found and downloaded Sebsky. neat program, but I haven’t been able to get a conversion to work yet. everything still drifts just as bad. i’m sure i’m doing something wrong in the process, any ideas? I would also love to know how to see what specs the audio was recorded at.

thanks

j-dog edits
jwalkerdrisko@mac.com

[Tony]

I hate to say it but somewhere in the chain the decision not to record audio to the camera @#$%% you up.

Some DP’s don’t want the extra cable dangling from the camera. Othertimes the audio guy just is too damn lazy to provide the proper audio snake to the camera so he can feed sound and listen to a audio return for confidence monitoring. Or yet another reason would be the sound guy insists the audio on the camera is not good enough and that the external audio recorder is the only way to get quality audio.

I won’t argue any of the logic behind these excuses except to say the responsiblility lies with the production company or editorial department to demand steps be taken to reduce the amount of time wasted in post production with attempts to fix field production issues.

The single greatest failure in production is the lack of detailed analysis of how precisely to accomplish the post production workflow before a single frame of footage has been shot.
In order to succeed you must first start at the end of the chain and work your way backwards to discover all the loopholes.

You did not mention how the timecode was jam synced. Did you use a lockit box or Deneke SB-T timecode generator to slave the audio recorder so the camera and did the audio recorder have common timecode? Did you shoot a smart slate with has visual timecode as a reference?
What was the frame rate on the audio recorder. Was the timecode NDF or DF?

I would advise taking the files to a professional audio facility and hire them to assist in fixing this nightmare.

Learn from this experience and never allow yourself again not to have a backup plan or secondary audio recording as a fallback.

There is no such thing as “we’ll fix it in post” …. at least not cheaply.

Good luck,

Tony Salgado