Welcome, Guest
Username: Password: Remember me

TOPIC: Multicam 23.98fps in a 25fps timeline pitch issue

Multicam 23.98fps in a 25fps timeline pitch issue 25 Oct 2019 20:36 #102263

  • blaxh404
  • blaxh404's Avatar
  • OFFLINE
  • Fresh Boarder
  • Posts: 3
  • Karma: 0
Hello everyone,
I am new here and I am posting a question which has been discussed over and over after a few google investigations, unfortunately none had a decent answer to my current situation.

I am editing a live video of 45 minutes in a multicam setup with 12 angles (I am using FCPX 10.2 on El Captain). My multicam uses proxys and cameras frame rate are all over the place (23.98, 24 and 25 fps). My multicam itself (set at 23.98) has however no sync or pitch issue as it has already been pointed out in other threads, the problem only lies on the timeline.

I used a 25 fps timeline with a 23.98 fps multicam without noticing the slight acceleration and a pitch shifting towards the highs. I am actually extremely screwed now since my project is reaching the end after hours, days and weeks of editing. I was aware of the project settings "25fps" and I thought about finishing the project, backing it up and trying to change this option.. however I didn't thought I was gonna be greyed out...

I checked everywhere and it seems that there are no answer to this problem. People say that its better to restart the edit, however it is really not an option in my case since it will take me way too long..
I am thinking about maybe exporting the video and then slowing down by the factor 23.98/25 = 0.9592 and then adding the audio track on top of that. What do you guys think? I really don't want to denaturate the audio, this is my main priority.
It is really weird that final cut doesn't allow anything like this, all the potential settings are greyed out. I understand It will affect many timecodes and probably the edit, but if I only need to readjust some cuts, its definitely different than restarting from scratch.


I hope you can bring some light to my idea and maybe providing me a solution, otherwise I will probably start a war against finalcut after loosing all my tears of distress.

let me know if something is still unclear, I really need help

Thanks !
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 26 Oct 2019 15:04 #102275

  • dgwvideo
  • dgwvideo's Avatar
  • OFFLINE
  • Platinum Boarder
  • Posts: 1933
  • Thank you received: 228
  • Karma: 32
I can't determine your pitch issue as that generally has more to do with the audio sample rates of the individual clips than it does the framerate of the project those clips are in. BUT - while you cannot alter the timebase of a project once clips are dropped into the timeline of a given project, you can create an entirely new project with whatever timebase (framerate) you desire and then copy all the clips from the existing project into the new project. This will maintain your edits and the project will now be at the new framerate. Maybe this will help with part of your problem.
Creating history....one edit at a time !
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 26 Oct 2019 15:16 #102277

  • blaxh404
  • blaxh404's Avatar
  • OFFLINE
  • Fresh Boarder
  • Posts: 3
  • Karma: 0
Thanks for your reply! I unfortunately dont know much about the audio sample rate. What i can tell you is that the multicam setting has the same audio sampling rate as the timeline (48kHz). I am 99% sure that the problem comes from this FPS setting.

Actually, i tried to paste it on another project but this is also greyed out. (sorry its in french). Its means that it adapted the FPS from 23.98 to 25 and i cant change that. Even if my project setting is at 23.98. I did an experiment is a new project (23.98fps setting) and I added my multicam from the inspector unedited. No issue, the sound was fine. Then i pasted the whole content of the other project and it was shorter! (due to this FPS difference, and the pitch was also higher) The timeline was also messed up since some clips were not aligned as they used to before.

Hope its more clear and that you have an idea.

I feel like my only solution is to export the whole project in this pitched up version, then created a new timeline with this whole printed video and slowing it down at 96% with the "non conserved pitch" setting.. I tried for short clip and it seemed to work, I dont know how it can affect the audio and video render on the whole project though.

Have a good day!
Attachments:
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 27 Dec 2019 12:07 #103564

  • blaxh404
  • blaxh404's Avatar
  • OFFLINE
  • Fresh Boarder
  • Posts: 3
  • Karma: 0
I still can't solve this issue, i tried to slowdown the whole exported video using twixtor, I used a slowing percentage as 95.92% (23.98/25) and then added the correct audio to the slowed down file (which should perfectly match) but there is a slow drift in the audio sync. I really don't understand all of this... I hope somebody sees this problem better than me, its starting to be urgent :unsure: :(
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 28 Dec 2019 04:30 #103603

  • Axel
  • Axel's Avatar
  • NOW ONLINE
  • Platinum Boarder
  • Posts: 547
  • Thank you received: 68
  • Karma: 10
blaxh404 wrote:
I still can't solve this issue, i tried to slowdown the whole exported video using twixtor, I used a slowing percentage as 95.92% (23.98/25) and then added the correct audio to the slowed down file (which should perfectly match) but there is a slow drift in the audio sync. I really don't understand all of this... I hope somebody sees this problem better than me, its starting to be urgent :unsure: :(

I am very astonished that you got a proper synch (but not with one external audio source?) with mixed frame rates, but be it as it may, I may help you nonetheless.

Your Twixtor comment proves that you confuse frame rate conversion with frame rate conforming. FCPX changes the speed of 23,98, 24 and 25 if you mix those three. It sacrifices realtime for smooth playback. Because usually one would detect stuttering motion through a skipped or repeated frame per second sooner than a slight change in pitch.

I thought that FCP automatically corrected the pitch like it does with obvious speed changes, but maybe not. There is, however, an audio effect called "pitch", did you check that?

blaxh404 wrote:
I feel like my only solution is to export the whole project in this pitched up version, then created a new timeline with this whole printed video and slowing it down at 96% with the "non conserved pitch" setting.. I tried for short clip and it seemed to work, I dont know how it can affect the audio and video render on the whole project though.

You can throw a 25p clip / whole master into an empty 23,98p timeline and vice versa. Will be either shorter or longer, because it's automatically conformed (not converted like with Twixtor). What about the pitch? Don't know off the cuff, tell us later.
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 28 Dec 2019 10:01 #103611

  • joema
  • joema's Avatar
  • OFFLINE
  • Platinum Boarder
  • Posts: 1321
  • Thank you received: 275
  • Karma: 26
blaxh404 wrote:
I still can't solve this issue, i tried to slowdown the whole exported video using twixtor, I used a slowing percentage as 95.92% (23.98/25) and then added the correct audio to the slowed down file (which should perfectly match) but there is a slow drift in the audio sync. I really don't understand all of this...

As dgwvideo said on 27-Oct, you can copy/paste your 25 fps timeline to a 23.98 or 24.0 fps timeline. This might help, and is easy to try.

(1) Create the new project using File>New>Project>Use Custom Settings, and in that dialog pick your frame rate.

(2) In the old timeline, select all clips with CMD+A, then copy with CMD+C.

(3) In the new timeline paste all clips from the old timeline with CMD+V.

If doing this between 23.98 and 29.97, you risk having to re-adjust clip borders due to the cumulative effect of rate conforming imprecision on many small (possibly overlapping) clips. However -- you only have 23.98 24.0 and 25.0. In that case I think the rate conforming algorithm is simply alter speed, so this may avoid the clip border issue.

When using the "alter speed" rate conforming algorithm, I think FCPX automatically applies audio pitch correction. If not there is a built-in audio effect called AUPitch. So rate conforming between 23.98/24.0/25.0 will affect camera audio unless resampled. External audio has no frame rate, so I think that must be handled manually.
Last Edit: 28 Dec 2019 10:06 by joema.
The administrator has disabled public write access.

Multicam 23.98fps in a 25fps timeline pitch issue 28 Dec 2019 13:15 #103613

  • FCPX.guru
  • FCPX.guru's Avatar
  • OFFLINE
  • Platinum Boarder
  • bbalser.com
  • Posts: 2943
  • Thank you received: 391
  • Karma: 34
Have the audio sample rates of these clips been verified?

I'd have taken it all into Compressor and made files of the same frame/sample rate before starting. That's just me. Seems it would avoid time-consuming troubleshooting like this. Due to nightmares like this in the past, I'd never do multi-cam with combined frame/sample rates.
The administrator has disabled public write access.