Recording with audio playback slowed down 65% what speed do I need to speed the video back up to to get it into real time?

Ian R. Brown wrote:

If you have slowed the video down in FCP X all you need to do is click on the Retime button, select Normal 100% and it will go back to its original state.

Hi

No, I think you misunderstand me. I havnt slowed the video down.

The video is still at 100% Normal, what I need to do is make the video quicker so that it matches up with the 100% Normal Audio (that is currently 65% slower).

This will make it look like everyone is running round in the video but the singer will look like theyre lipsyncing at the correct 100% Normal Audio speed.

shippo_uk wrote:

Ive recorded a test video with audio/music playback slowed down 65% what speed do I need to speed the video back up to to get it into "real" time?

If I'd slowed the audio playback down 50% I would make the video 100% faster.

If I'd slowed the audio playback down 100% I would make the video 200% faster.

So its obviously somewhere inbetween speeding up by 100-200%

Sorry but its melting my brain today and I cant remember the calculation.

thanks

I think I'm about to answer my own question here.

50% slower audio x 2 = 100% faster

100% slower audio x 2 = 200% faster

therfore

65% slower audio x 2 = 130% faster

xfggfx wrote:

When you say 65% do you mean that you were miming to the song (for example) at 65 beats per minute instead of 100bpm? in which case you sped the music up (to get it to normal) by 100/65 %

If you mean you reduced it by65% then it was playing at 35% on the mime day and you have sped the music up by 100/35 % to get it back to normal.

The video presumably would have to be retimed by the same percent either way...now where is my calculator...

Someone please check my logic as i am quite likely to be completely wrong...

Hi

Lets take your example.

The song should be at 100bpm. I slowed it down by 65%, so its then played back and mimed to at 35bpm (100bpm-65%=35bpm).

To get it back to 100bpm........I need to........arrrrggghhh my brain hurts.

hey all

Thanks for the advise on this. I will explain a little more what am have/am intending to do.

I have used Audacity to slow the song down (Effect>Change Tempo)

Audacity will allow me slow the original song down by up to 99% (Or anything in-between up to 3 decimal places)

Unfortunately I am working to a time restraint of 12 minutes per clip (as my DSLR will only allow up to a 12 minute clip).

The song at normal speed is 4 minutes long.

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Originally I slowed the audio down by 50% (Making the audio 8 minutes long), lip synced to it using a rasta blaster and recorded the video using my DSLR at 720p 50fps.

I then imported the video and audio I had been lip syncing to into FCPX.

I sped up the video by x2 (equivalent to speeding it up 200%)

Retime>Fast 2X

Layered the PROPER normal speed audio back over the top and all was fine.

Test video complete.

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(You can ignore the 65% slowed down audio I mentioned earlier if you like, that was just an example of a slower than 50% audio test)

Firstly what I really want to do is to be able to slow the AUDIO down as much as possible (But still within the restraints of only being able to adjust FCPX retiming within a whole 1 percentage in the final video edit), but have the AUDIO of the song as near to/under 12 minutes as possible.

I will then re-record the video again to this new slowed down audio.

Secondly I will speed up the video from 12 minutes to 4 minutes.

Thirdly I will layer the correct 100% Normal AUDIO on top.

The FINISHED video should then look like everyone is wizzing around at high speed but the guitar playing/lyrics look like they are being played/sung at the normal speed.

Whatever happens (due to the constraints of FCPX) I need the calculations to work so that FCPX is retimed exactly to a whole 1% for the final video to sync up correctly.

So what I need to know in a nut shell is:-

What calculation do I use to work out the percentage to slow a 4 minute song down to a 12 minute song?

What calculation do I use to work out the percentage of how much I need to then speed the 12 minute video up to turn it back into a 4 minute video?

My mind is melting 🙂