Menu

avidMXFinfo NTSC DF madness

Help
bouke vahl
2011-10-18
2013-04-25
  • bouke vahl

    bouke vahl - 2011-10-18

    Using AvidMXFinfo on imported QT clips with DF TC (have no digitized ones..)
    It seems the timecode for DF is written as NDF, but with twice the amount of frames dropped.
    A clip showing TC 01:00:00;00 (d) in Avid, analyzed with AvidMXFinfo:
    Start timecode = 107784 samples (00:59:52:24)
    FramesToTC(107784, DF) = 00:59:56;12d

    But then TCtoFrames(00:59:56;12, NDF (!!!) gives 107892
    Then, FramesToTC(107892, DF) = 01:00:00;00d

    What gives?

    Now, of course i can counteract this with a bit of math, but i can't find any reference if the clip is indeed treated as DF or NDF by avid.
    Am i missing something or is this just a limitation?

    tia,
    Bouke

     
  • Philip de Nier

    Philip de Nier - 2011-10-18

    Do you have a sample file I can look at?

    I can't think of reason why there would be twice the number of frames dropped in the calculation.

    Maybe Avid is showing a 'playout' timecode extracted from the material package rather than a 'source' timecode (e.g. when there is a source tape) which avidmxfinfo displays.

    Philip

     
  • John Fletcher

    John Fletcher - 2011-10-19

    Yes, it would be interesting to see an example file.

    107784 NTSC samples is 00:59:56;12 DF or 00:59:52:24 NDF

    John

     
  • bouke vahl

    bouke vahl - 2011-10-19

    Guys,
    thanks for looking into this!
    Sample is here:
    http://www.editb.nl/avid/

    Let me know if there is anything more i can give you.
    Bouke

     
  • Philip de Nier

    Philip de Nier - 2011-10-19

    It was a bug in avidmxfinfo. The CVS has been updated with a partial fix. avidmxfinfo will now output: Start timecode = 107892 samples (00:59:56:12)

    It's a partial fix because it should be extracting drop frame info and the conversion to a frame count at output edit rate isn't very helpful; it should show what you see in Avid. For now it outputs the frame count and NDF timecode and a better solution will have to wait for another day…

    Philip

     
  • bouke vahl

    bouke vahl - 2011-10-20

    Philip,
    Thanks.
    FWIW, MXFdump seems to be able to see the DF / NDF flag, so i'll run that alongside for now.

    Bouke

     

Log in to post a comment.

Auth0 Logo