-
Slowing down audio and video to then sync when sped up
Ok, so am very new to this, but what I did and trying to figure out is the following:
I slowed down an audio track in FCP by 40% ie to 60% (in the Modify > Change Speed section) then I recorded the video with singing.
Then I brought it all in and sped it up by 40% to 140% and brought in the original audio (which of course is at 100%), BUT it doesn’t sync up.
I must be getting conversion rates wrong. Am currently trying to speed it up by 160% as the footage seems too slow for the audio.
If anyone knows the conversion rates let me know. Have a feeling they are 1.25? Cheers!
Many thanks!
-
7 Replies
-
SOLVED, but if anyone is interested 165% did indeed work, ie adding the 40 plus a quarter on top did sync up with the original audio.
-
Well, logic would suggest that you’d need to speed up by 166.6666666666666666 (etc) %
so 165% would be close enough (i.e., it would take a while before you’d notice it slipping) -
Hi Andrew, Cheers for that….so where am I going wrong…ie. what’s the calculation?
-
You start with 100 apples. You take 40% of them away, you have 60 apples. You want 100 apples again. If you add 40%, that’s 40% of 60 apples, which is 24 apples. You want 40 apples over your 60 apples, which is 2/3, which is 66.66667%. After you slow down the footage, the reference frame changes with it.
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Many thanks!
The ten year olds amongst this forum will be grateful that you used apples to explain this 🙂
-
It’s how Ms. Diane taught me this and, to this day, I still visualize apples when working with fractions. No nagging intended. OK, maybe just a little. 🙂
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Hehe, well thank you. I appreciate you taking the time to answer no matter how 🙂
Reply to this Discussion! Login or Sign Up