Can Pulldown Removal Affect Sound Synching? at DVinfo.net

Peter Moretti · September 14th, 2007, 03:42 AM

I am plannig to record double to both my HV-20 and a Sound Devices 702 recorder. The recorder's audio track will be synched the camera's video and audio tracks in my NLE (Xpress Pro or Vegas).

Does removing the pulldown introduce any additional problems with synching externally recorded audio to the footage?

I don't believe it should, but I've found sometimes the only stupid question really is the one you didn't ask.

THANKS A LOT for the help.

Glyn Williams · September 14th, 2007, 05:30 AM

It could.

Reverse telecine is converting the 24p material in a 60i container to clean progressive 24p.

But... the 60i is really 59.94fps - and reverse telecine should be producing footage at 23.976fps. Almost 24 but not quite.

If the process you use puts the footage into a 24fps container, the audio could end up drifting slowly out of sync in long shots.

By my reckoning, a single 5 minute long take would drift by 1/3 second by the end.

Wes Vasher · September 14th, 2007, 08:12 AM

That's a good question Peter. My thought would be if you stick to 23.976 as Glyn pointed out you'll be fine but without doing a several minute test to find out who knows for sure. One would want to use a clapper throughout the video so you'd have some peak audio points to check for sync.

September 14th, 2007, 03:42 AM	#1
Peter Moretti Trustee Join Date: Mar 2007 Location: Sherman Oaks, CA Posts: 1,259	Can Pulldown Removal Affect Sound Synching? I am plannig to record double to both my HV-20 and a Sound Devices 702 recorder. The recorder's audio track will be synched the camera's video and audio tracks in my NLE (Xpress Pro or Vegas). Does removing the pulldown introduce any additional problems with synching externally recorded audio to the footage? I don't believe it should, but I've found sometimes the only stupid question really is the one you didn't ask. THANKS A LOT for the help.

September 14th, 2007, 08:12 AM	#3
Wes Vasher Major Player Join Date: Jan 2006 Posts: 440	That's a good question Peter. My thought would be if you stick to 23.976 as Glyn pointed out you'll be fine but without doing a several minute test to find out who knows for sure. One would want to use a clapper throughout the video so you'd have some peak audio points to check for sync. __________________ Clips \| Stills

September 14th, 2007, 05:30 AM	#2
Glyn Williams New Boot Join Date: Jul 2007 Location: Sheffield, England Posts: 22	It could. Reverse telecine is converting the 24p material in a 60i container to clean progressive 24p. But... the 60i is really 59.94fps - and reverse telecine should be producing footage at 23.976fps. Almost 24 but not quite. If the process you use puts the footage into a 24fps container, the audio could end up drifting slowly out of sync in long shots. By my reckoning, a single 5 minute long take would drift by 1/3 second by the end.