Audio from slow-mo

Hello, I can't understand how the workflow with 60fps clips works.

Lemme explain: let's say I shoot 24fps with an off speed recording of 60fps. (most of the time because I want to have the OPTION to use the clip either on regular speed or slow mo)

When I import my clips on Premiere the VIDEO CLIP is at 60fps but the AUDIO is 24fps.

So, when I have to use them at regular speed, I have to unlink the audio, speed up the video and relink.

MOST annoying is that I cannot preview them with the sync audio....

Is there someting I'm missing or doing wrong?

Thanks

When filming in off speed mode audio and video will always be out of sync because they are not interlocked together like in normal mode. So if you do a 60fps into 24fps project frame rate your video will be slowed down by 2.5 (= playback at 40%) but your audio will still be in real time.

Why don't you just shoot in regular 60p and when necessary slow down the footage in Premiere by interpreting it as 24fps. That way your audio will stay in sync no matter what.

Thank you for your reply!

I'm brand new in the Blackmagic world. My understanding was that,in order to shoot high frame rates you need to activate the off speed function.

I'll study the menu better now, because of course my first choice was to just shoot 60 fps and eventually convert to 24fps.

From what I understand the slow mo option only changes the FPS metadata to change how it's going to be interpreted when you bring it into a NLE, or when you play it to preview it you would like to have it slowed down automatically. If you don't need this, it might be better to avoid using the off speed feature. if anyone can confirm what I'm saying that would be great

I want to have the OPTION to use the clip either on regular speed or slow mo

I think it's best to make that decision when you shoot, not after.

I agree. My problem is my lack of knowledge of the whole setup menu

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From what I understand the slow mo option only changes the FPS metadata to change how it's going to be interpreted when you bring it into a NLE, or when you play it to preview it you would like to have it slowed down automatically. If you don't need this, it might be better to avoid using the off speed feature. if anyone can confirm what I'm saying that would be great

No that isn't the case.

If shooting off speed - video and audio are not sync interlocked in the camera hardware anymore.

For example:
Normal mode 60 fps
-> audio is clock-sync to the video / audio and video are realtime
-> interpret frame rate in post to 24 fps - audio and video will stay in sync and playback at 40%

Off speed mode 24/60 fps
-> audio is unlocked and will drift over time / audio is 100% realtime but video is at 40% speed
-> during playback audio will stop after 40% playtime
-> interpret frame rate in post to 60 fps - audio and video will playback at 250% and audio will stop after 40% playtime (unless the tracks get un-linked and only video gets speedup)

That is also the reason why you shouldn't record in 60/60 fps instead of 60fps because audio will drift over time. (Unless you do not care about audio)

Awesome. I believe we got the perfect answer. Thank you!

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-> interpret frame rate in post to 60 fps - audio and video will playback at 250% and audio will stop after 40% playtime (unless the tracks get un-linked and only video gets speedup)

Good points, the ones who shoot the video should tell the ones who edit to be careful with that and think about this NLE feature. This is doable in Premiere Pro, probably all the NLEs out there too

That is also the reason why you shouldn't record in 60/60 fps instead of 60fps because audio will drift over time. (Unless you do not care about audio)

Did you mean 24/60 (or even "anything different than 60" / 60) ?

Call me crazy: if you're shooting any non-standard speed, my advice would be to record sound on a separate audio recorder, synced with the camera. And use a clap-stick. (Even better a timecode slate.)

Did you mean 24/60 (or even "anything different than 60" / 60) ?

No. I meant any combination in HFR mode will have non-interlocked audio.

Exactly. And that means trouble.