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Importing & Editing 23.98 FPS 16:9 NTSC Footage has jerky cadence

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  • Importing & Editing 23.98 FPS 16:9 NTSC Footage has jerky cadence

    We are using Edius Pro 4.5 to edit clips of existing mpeg-2 films. None of the Edius Pro 4.5 sequence presets seem to match the content of the films which are typically (NTSC 23.976 Progressive 16:9 MPEG-2). The best we have found for importing this type of mpeg files without frame blending is to use the PRESET SD 24HZ 720x420 23.98p over 59.94i 16:9 setting.

    But, after bringing the file into the project, a A:B:C:C cadence is introduced, adding a 4th duplicate frame of every third frame. I believe we may be able to get rid of this jerky mostion effect on export using ProCoder 3, which we don't yet have. However, I am wondering if there is a better preset out there to work with that doesn't introduce this lousy cadence to our otherwise perfectly smooth original MPEG-2 file.

    Any thoughts?

  • #2
    Does your source have the 3-2 pulldown flag enabled (ie, it reports 29.97 display rate, but encoded data is 23.976)?

    If so, I would simply edit it in 29.97, though you will have to be mindful of cadence, then run the output through ProCoder 3 with the Inverse Telecine filter to get back to 23.976.

    You could also try the 23.98pA project setting instead if you like.


    • #3
      The clip appears in the procoder express viewer as a 23.976 clip to begin with. It also reads this way in MediaViewer prior to import. So, it seems to be a 23.976 clip. Is it possible the readers are wrong, and it is actually flagged 29.97?

      Is there not a native preset that you know of for editing 23.976 material, or even a true 24fps preset for editing previously reversed progressive footage?

      Regarding the 23.98PA setting, that just gives me the same A:B:C:C:A:B:C:C cadence as the 23.98P setting. Is there not just a 24 preset? or just a 23.98 preset?


      • #4
        Sounds like the clip really is 23.976p (otherwise the display rate would show 29.97).

        The problem with the 23.98p(A) over 59.94i presets are that while the timeline is working in 23.98p (23.976p), the output from hardware is 59.94i, causing the weird cadence you're seeing on the output. They're really designed more for handling "24p DV" type footage where it's 59.94i with flagged fields to discard.

        The next update for EDIUS introduces true 23.976p presets, but for HD, not SD resolutions (well, at least not for OHCI, could be different if you have EDIUS hardware - Kenneally might know better than I do).


        • #5
          Thank you so much for your quick responsive help. I had a feeling there was some missing presets as I have worked in Final Cut and Avid for years and they do have those settings, though they took their time getting them. I am disappointed to not be able to edit basic 23.976 natively in 720x480 res, since it's pretty standard more and more with mpeg delivery over the web, especially at our company. Something for Edius to consider, as it would be a shame to go HD considering web delivered HD MPEG isn't entirely there yet.

          But, thanks for your help. I guess we'll have to do a workaround with Procoder doing an inverse telecine output.


          • #6
            You're welcome. I hope to see EDIUS "detached" from video-centric hardware output in the future. It's pretty high on the feature request list (top 20).


            • #7
              Problem Solved

              So, after a lot of wasted time and difficult inverse telecine processes, i have discovered the answer to the issue of an unwanted (edius introduced) jerky cadence on 23.976 mpegs with every 4th frame duplicated.

              Answer: I simply clicked "Don't Use PTS" and everything plays back perfect. No duplicate frames. No jerkiness. Just perfect 24fps. So, what is this PTS, why does it have to be turned OFF and why wasn't this suggested earlier?

              I'm curious. Anybody have an explanation.


              • #8
                It stands for Presentation Time Stamp. It is usually suggested to not use this in conjunction with MPEG 2 capturing if there are green flashed in your captured file. The DTS/PTS stamps in the MPEG stream are used to maintain sync, so it is best to only enable Don't use PTS when it is absolutely necessary.

                I certainly did not think of it in conjunction with your problem of existing files.