Latest post Tue, Jul 2 2013 1:30 PM by S.Clements. 4 replies.
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  • Thu, Jun 27 2013 1:41 PM

    • S.Clements
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    How to Fix an Audio-Related Frame Rate Import Error After Start of Editing?

    Hi,

         I have a bit of a complex problem I was wondering if someone could help me with.

     

         I have a feature documentary in which all the footage was shot at either 24 or 25 fps (final inntended target is 25 fps).  The audio was recorded as either 48 khz 24 bit, 48 khz 16 bit or 44.1 khz 16 bit

     

         At the begining of the project, I brought the 24 fps footage into a 24fps project.  I also brought audio that syncs up to this footage into the same project, so it came is with a frame rate listed as 24 fps (at the time I didn't realise there would be 25 fps material coming in).

     

         When I discovered 25 fps footage for the project, I created a new 25fps project and imported the bins from the 24 fps project into it.  I then synced the 24 fps footage with the audio that was brought in as 24fps in a 25fps timeline.  However, there was a problem with this audio - it was recorded at 44.1 kHz 16 bit - all the rest of the material was 48 khz 24bit or 16 bit.  This caused great problems with mixed sample rates (I'm pretty sure you can mix bit depths fine, but could be mistaken about this)  

     

         So, I decided to transcode all my 44.1 audio to 48 khz in the main 25fps project and relink.  However, when I did this, none of the newly transcoded clips could be relinked to the audio clips synced to the 24 fps footage.  I think this is because the original 44.1 audio clips had a listed frame rate of 24 fps.

     

       So, now, I'm not sure what the best solution to this is.  Does it matter quality-wise if the sound is ingested as 24fps or 25fps?  Does Protools or any other DAW even recognize what "fps rate" an audio clip is set at?  If it doesn't matter at all quality wise, should I just make a separate 24fps project and re-trranscode the 44.1 audio to 48 and then bring the bins into the 25fps project and relink?  Or, should I re-trancode all the 44.1 audio to 48 in the 25 fps project and somehow re-sync it? (this would be a time consuming process)

         I have a lot more work to do with this feature, so want to make sure I have the cleanest possible solution to make everything run smoothly for the duration.  Any thoughts would be appreciated.  Many thanks.

     

     

     

     

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
  • Thu, Jun 27 2013 5:25 PM In reply to

    Re: How to Fix an Audio-Related Frame Rate Import Error After Start of Editing?

    You should find a way to either pull all 25fps stuff down to 24 or pull all 24fps stuff up to 25. Mix & Match will add motion adapters, which will not give you the greatest end result when you mix 24 and 25. Just too hard a conversion to pull off nicely.

    Here's a PDF on mixing 25-24 I wrote some years ago.

     

    Relink, AFAIK, only works if your project frame rate and the clip frame rate and media frame rate match.

    I bet you would have been able to perform a Sample Rate Conversion on the synced clips, rather than re-import. Or you could have (and still could) perform a sample rate conversion on the 24 stuff in the 24 project.

    Sound has no frame rate, but the metadata of the clips inside MC do have an annotated frame rate. To Pro Tools, it should not matter. It only plays back samples.

     

    Media Composer Symphony | PT Ultimate | Win10 HPZ | OSX MBP | ISIS5000 [view my complete system specs]
  • Thu, Jun 27 2013 7:56 PM In reply to

    • S.Clements
    • Top 150 Contributor
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    Re: How to Fix an Audio-Related Frame Rate Import Error After Start of Editing?

        Thanks, Job!  All of that is super helpful.  Because the overwhelming majority of my material is 25 fps and UK television is the most desiraable destination, I wish to keep the project at 25fps.  According to you, I should then convert the 24fps material to 25fps.  I'll try a few tests converting with Adobe Media Encoder, Compressor and Avid.

         It's too bad I won't to be able to reconnect the newly created 25fps clips to the 24 fps clips already edted into timeline.  I wish you could change the frame rate after the fact (because the clips are actually edited at 25fps)  Not quite sure how I'm going to manage recreating the editing with the newly created clips.  That's why I was thinking it might just be best to do my conversion at the end using fluid motion rendering.  However, the mixed frame rates are causing a lot of problems in the editing.

         Thanks again!

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
  • Thu, Jun 27 2013 8:08 PM In reply to

    Re: How to Fix an Audio-Related Frame Rate Import Error After Start of Editing?

    S.Clements:
    According to you, I should then convert the 24fps material to 25fps.  I'll try a few tests converting with Adobe Media Encoder, Compressor and Avid.
    None of those will actually help you out. They will all just perform 24-25 conversions without speedups, they will interpolate or blend or duplicate fields or frames.

    Read the doc, there are ways to trick audio to a higher speed, and Cinema Tools lets you pull up or down QT files between 24 and 25. QT Imports and QT AMA-linked footage can also be pulled up (video only, you'll need to do sound separately).

    S.Clements:
    I wish you could change the frame rate after the fact (because the clips are actually edited at 25fps
    But it would never be frame accurate. Which is what you'd want.

    And even more so, this type of stuff you need to get right from the get go, or you will be in trouble all the way through post production, until way, way into delivery time.

    S.Clements:
     Not quite sure how I'm going to manage recreating the editing with the newly created clips.
    Just do it manually. Bite the bullet, put in the hours, it will save you headaches later on.

    S.Clements:
    the mixed frame rates are causing a lot of problems in the editing
    You can mix certain types of frame rates, but 24-25 is generally a bad idea.

    Whoever thought it was wise to mix them during shooting is a full blown idiot.

    Media Composer Symphony | PT Ultimate | Win10 HPZ | OSX MBP | ISIS5000 [view my complete system specs]
  • Tue, Jul 2 2013 1:30 PM In reply to

    • S.Clements
    • Top 150 Contributor
    • Joined on Sun, Jul 3 2011
    • London, United Kingdom
    • Posts 812
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    Re: How to Fix an Audio-Related Frame Rate Import Error After Start of Editing?

         Thanks again, Job.   I've been over your PDF several times.  I am able to use Cinema Tools to convert the quicktime files from 24 fps to 25ps (I'm surprised to see that the quicktime is changed instantaneously - being some short of metadata change I imagine?).  

         These 25 fps clips have sound within the quicktime (as well as separately recorded sound in some cases).  Based on your PDF, it appears as though I import these converted quictktimes into Avid and then adjust the sample rate in the Avid from 48000 to 50000.  However, this brings me back to the problem of having mixed sample rates in the timeline, which appears to be just as much of a problem as having mixed frame rates.   Admittedly, I'm having a bit of a problem understanding the PDF because it is geared towards the 25fps to 24fps Avid film project workflow and mine is the reverse situation, so I'm trying to think about it in the reverse direction.  

         After comparing 24 fps files dropped into a 25fps sequence and the 24fps files converted by cinematools beforehand, I do see what you mean about the unconverted 24 files just resorting to a speed change to fit and the converted files being frame accurate.  I wonder why Avid doesn't address this within media composer?  it is unfortunate that for the mac, Cinema Tools is the only easy option.  I think a lot of people just want to distance themselves as much from Final Cut Studio as possible.  It would be great to have MetaFuze for mac to have an Avid based solution, but I've seen the reasons stated by Avid on here as to why it's not a focus of theirs. 

     

    Avid Media Composer 8.3.1 Macbook Pro (Retina, 15-inch, Mid 2014) 2.8 GHz Intel Core i7, 16GB Ram Mac, OS 10.10.2 [view my complete system specs]
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