Hello. I am working on a 25P multicamera project. In one of the cameras (Blackmagic) they have used the high speed recording (HFR) function that does not maintain the synchronization between video and audio. This has produced 60fps files (which when linked from a 25P project are in slow motion) with the audio playing at normal speed (audio ends before the middle of the video). When working on the timeline the Media Composer crashes and I have to restart it. I have been able to continue working if I remove the audio of the HFR clips from the timeline but there are still crashes. Is there a way to match the audio speed to the video speed? (and not with timewarp since I need to do multi-camera with 25P material). Thank you

H, 

Which codec are these files encoded in? Is this linked or Avid managed?

Prores LT. Linked

Tentaor:

In one of the cameras (Blackmagic) they have used the high speed recording (HFR) function that does not maintain the synchronization between video and audio.

That is precisely the way HFR is meant to work - it is slow-mo, destined to be played back at the target rate of 24/5p or whatever. Therefore the sound will be far out of sync. It is an anomaly of BMD cameras that you are even able to record sound in HFR. I own an Ursa camera and HFR, or High Frame Rate, is a button that you press for instant slow-mo, the sounds continues to be recorded at the nominal rate. HFR is not 60p standard frame rate, in this instance, and sound should be disregarded for ingest. 

If it was meant to be sync rushes, then your cameraperson made a mistake by not exiting HFR mode. Unfortunately there is little you can do to remedy it, since 60p into 25p does not make, no matter how you divide it.

The Canon C300s also do this thing of recording the audio with slow mo pics. As Mercer says, if it's meant to be in the group then the camera person should be feeling sheepish.

Otherwise, remove the audio, group all your 25p footage together and then lay the HFR stuff on V2 above the grouped footage as closely as possible to a common sync point - example - someone smashes a glass so find the smash at 25p and then find the smash at 60p and use sync point editing to line them up.

I have to do this often and I find it the most sensible way to deal with it. Editors can then just pop up a layer to use the slowmo clip if necessary.

Andi

Thanks.  I assume that this workflow is the one I should use but unfortunately I don't understand why Media Composer hangs when having these files in the timeline

Thanks.  I assume that this workflow is the one I should use but unfortunately I don't understand why Media Composer hangs when having these files in the timeline