Smoothly Convert 30fps video to 23.98fps? Detelecine/Inverse Telecine?

Discussion in 'Digital Video' started by TheSpaz, Oct 30, 2007.

  1. TheSpaz macrumors 604

    TheSpaz

    Joined:
    Jun 20, 2005
    #1
    Say I record The Office with EyeTV. It records at 30fps but, The Office runs at 24.98fps so that means there are extra frames that don't need to be there. Is there any software that can be used to delete the duplicate frames to make a 30fps file run at 24.98fps smoothly?

    When I try to compress it forcing 24.98, it makes the video more jumpy and jerky because it still adds duplicate frames.
     
  2. huntercr macrumors 65816

    Joined:
    Jun 6, 2006
    #2
    What software are you using for your edit? Compressor 3 ( From FCS2 ) has the reverse telecine that you're wanting.

    Depending on what your output format is, you shouldn't have too much of a file size issue ( if that's what you're concerned about ) with the extra fps... if you use a codec that uses B frames, you're going to almost get the same compression out of it because those extra frames are identical and can be stored as such.

    Good luck!
     
  3. trudd macrumors regular

    trudd

    Joined:
    May 27, 2004
    Location:
    Texas
    #3
    Perhaps you should try 23.98 (as 24.98 doesn't exist).

    However, I'm not sure if compressor would be able to tell which frames to remove. I've never had to remove pulldown.
     
  4. TheSpaz thread starter macrumors 604

    TheSpaz

    Joined:
    Jun 20, 2005
    #4
    Hah, yeah, I meant 23.98... sorrry. I'm using EyeTV Hybrid to record television shows to DVD format. I'm not using an editor but, I am using VisualHub and I don't think it has a reverse telecine option.
     
  5. Artofilm macrumors 6502a

    Artofilm

    Joined:
    Oct 12, 2005
    #5
    Umm,

    Im pretty sure all television in Canada and the US is shown at 30fps (or 29.97fps)

    Ive never heard of a tv show being shown in 24fps. That may be why you are getting a "jerky" flow to the video.
     
  6. Scandals macrumors member

    Joined:
    Nov 30, 2004
    Location:
    Canada
    #6
    Productions are shot on 24fps film or 23.98fps progressive video which is then interlaced to 29.97fps. They do this to get the filmic look and feel to the production. Often DVDs are encoded at 23.98fps in order to offer a better "progressive" image and save about 20% of the space resulting in higher quality image/more space available on the disc.

    Newer TVs are progressive and can actually deal with 23.98, but older ones can only show 29.97 and therefore the typical setup has the DVD player adding pulldown to the 23.98 DVD in order for it to display properly. Progressive scan players preserve the source 23.98 image and output it to a "modern" TV for the best quality possible.

    Anyhow, if you are recording off of SD cable then your source is most definitely 29.97fps interlaced. You are correct that at one point the program existed at 23.98 and therefore it should be possible to remove the 3:2:3:2 pulldown extracting the 23.98 source. I have done this with source material of various sort from a DVX-100 using FCP and it went off without a hitch. I don't see why you couldn't do it with TV programming, providing the interlaced source frames can be reconstructed into progressive frames. That is, that they haven't been modified somehow in the process of broadcasting, adding titles, etc... I know its a lot to grasp... :confused: I guess the only way to know is to try and see what happens! :) If you can, try the pulldown removal in FCP, it should analyze your footage and process it if everything is good...

    Look for "reverse telecine" as huntercr said.
     
  7. Nermal Moderator

    Nermal

    Staff Member

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    Dec 7, 2002
    Location:
    New Zealand
    #7
    I've also heard it called "inverse telecine" so keep an eye open for that too.
     
  8. TheSpaz thread starter macrumors 604

    TheSpaz

    Joined:
    Jun 20, 2005
    #8
    The problem is, I don't have FinalCut Pro. I'm really mostly concerned with encoding it for my iPod in a way that it won't come out jerky and so I need my encoder to be able to delete those unwanted frames. The other thing is, I noticed that Handbrake has a Detelecine option but, of course, Handbrake only encodes DVDs... go figure. Any software that's like Handbreak that will work for other video types besides DVD Discs?
     

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