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Activity Forums Apple Final Cut Pro Legacy Audio duration 1 frame too short

  • Audio duration 1 frame too short

    Posted by Carles Vila on March 28, 2019 at 12:53 pm

    Hi, i’ve been seaching forums and the web but cannot find if this is a known issue/bug or if it’s something related to my system
    I’m using FCP 7.0.3.

    When i import audio files into final cut , some of them are 1 frame shorter than they really are. This is very annoying because in my case these audios must be placed one after the other and this messes up sync.

    For example:
    Case1:
    I have a video and audio that are 27213 frames long. At 24fps this is a duration of 00:18:53:21. The audio is 24bit at 48kHz and has exactly 54.426.000 samples, as confirmed with several external audio editors. Everything matches mathematically.
    Both audio and video import Ok in final cut, it reports the correct durations in the browser window and when dragged into the timeline, in and out line up predictably.

    Case2:
    The video and audio are 22465 frames long. At 24 fps this is a duration of 00:15:36:01. The audio has 44.930.000 samples. This also matches mathematically.
    When I import this into final cut, the durations of the video and audio are reported OK in the browser window, BUT when the audio is dragged into the timeline, the last frame gets cut off for no reason !!!

    I could give you more examples, but the behaviour is that about 1/4 of the audio files I import, are cut 1 frame shorter at the end when I drag them to the timeline. I tried to find a logic but it seems to be random.

    Has any of you encountered this problem?

    Shane Ross replied 7 years, 1 month ago 3 Members · 3 Replies
  • 3 Replies
  • Michael Gissing

    March 28, 2019 at 10:38 pm

    All your files are actually 24 not 23.976 (or 23.98 as FCP calls it)? And your timeline is also exactly 24 too?

    If any files are flagged as 23.98 by Cinema Tools you can change their metadata to 24 if that is the issue.

  • Carles Vila

    March 29, 2019 at 10:33 am

    Hi Michael,
    Yes, everything is 24 fps or 25. I wouldn’t touch 23,89 fps with a with a laser pointer attached to a 10 foot pole ☺
    I am aware of the bug/feature of fcp where it silently flags audio as 23,98 and applies pull-down if the capture settings are set at 23,98, even when you never capture anything. It has bitten me several times.
    But this is not the case, as the sync issue would be proportionally bigger the longer the file is.
    It just cuts off the last frame randomly on long files or shorter files.

    I’m reading chapter 26 of the manual, maybe there’s a clue somewhere…

    Cheers

  • Shane Ross

    March 29, 2019 at 4:12 pm

    [Carles Vila] “I wouldn’t touch 23,89 fps with a with a laser pointer attached to a 10 foot pole”

    Why not? It’s the standard for internet and broadcast. 24 straight up is pretty much only for theater projection. Not being snarky, genuinely curious.

    Shane
    Little Frog Post
    Read my blog, Little Frog in High Def

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