Latest post Sat, Feb 2 2019 5:45 PM by Tom Swartwout. 4 replies.
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  • Thu, Jan 31 2019 1:12 PM

    subtitle NDF/ DF drift issue?

    I've made subtitles using the subcap generator.  We're sending a piece to the Philippines and we'd like them to be able to use VLC Player with an .srt file (different languages for different events).  Project is 23.98.

    I've exported my subtitles as a text file and used an online converter to make the .srt file.  When I look at my two files with TextEdit, they seem to be the same, and yet, in VLC, the .srt titles drift much like would happen if I had a drop frame/non drop frame issue.  By the end of a 45 minute video, the subtitles are a handful of seconds earlier than they should be - even though the time stamps on the .srt file appear to be correct.

    Anyone have a quick solution - an online tool that converts a .srt, .stl, or .txt file from drop frame to non drop frame so that I can test this idea out?  Or perhaps there's a tool to open up one of these files and change some "header" information?

    Thank you.

    Tom

     

     

    MC 2018.12 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.1/32GB RAM/GTX 780M 4GB/ ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Sat, Feb 2 2019 1:51 AM In reply to

    • jef
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    Re: subtitle NDF/ DF drift issue?

    You say the project is 23.98.  In that frame rate there is no such thing as drop frame TC.

    My hunch is that there was an issue when you used the "online converter".  Did it explicitly say it supported 23.98 (or 24)fps TC?

    I would inspect the file it produced and look for any frame numbers higher than 23.  This would be the tip off something was not done right be the converter.

    Jef

    Avid DS 11.0.2 R.I.P | MC "Well, it depends ..." mostly 8.10.0 but playing w 2018.11| OS 10.11.x - various MacPro Towers - home system MacPro... [view my complete system specs]

    _____________________________________________

    Jef Huey

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    Old Stuff  http://vimeo.com/album/3037796

  • Sat, Feb 2 2019 2:07 AM In reply to

    Re: subtitle NDF/ DF drift issue?

    Thanks Jef.  Yes, that's why it is so baffling.  In the end, I was able to fix the issue by using Subbits.  Bouke, kindly did the recalibration for me.   https://www.videotoolshed.com/product/subbits-subtitler/

    First, he made a straight .srt conversion with his software (thinking as you did that the online converter made a mistake) - the drift problem re-occurred exactly as before.  He then recalibrated the file from DF to NDF, and it fixed the problem.  Which doesn't really make any sense as you indicate given that 23.98 doesn't have drop frame.  

    Anyway, the new subtitle file is not perfect, it's off by a frame once in awhile, but at least it doesn't drift - which, for my purposes, is good enough.  And being off a frame once in awhile makes sense given that the time stamps from the .srt no longer line up perfectly with the 23.98 image.

    Maybe there's a bug somewhere connected to the export from Media Composer?  Maybe there's something particular to my sequence.

    For the moment, problem solved.

     

    MC 2018.12 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.1/32GB RAM/GTX 780M 4GB/ ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Sat, Feb 2 2019 2:51 PM In reply to

    • jef
    • Top 50 Contributor
    • Joined on Sun, Feb 26 2006
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    Re: subtitle NDF/ DF drift issue?

    Interesting.

    We use and like Subbits as well.

    Jef

    Avid DS 11.0.2 R.I.P | MC "Well, it depends ..." mostly 8.10.0 but playing w 2018.11| OS 10.11.x - various MacPro Towers - home system MacPro... [view my complete system specs]

    _____________________________________________

    Jef Huey

    Senior Editor

    Old Stuff  http://vimeo.com/album/3037796

  • Sat, Feb 2 2019 5:45 PM In reply to

    Re: subtitle NDF/ DF drift issue?

    Hi Jeff,

    Bouke from Subbits just emailed me:

    I'm paraphrasing what he wrote:

    23.976 is a NDF format. And, SRT is a format that works in actual time. This means that the conversion from Avid's .txt file to .srt should not just recalculate the frames to Msecs, but also do  NDF to DF timing conversion.  
    MC 2018.12 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.1/32GB RAM/GTX 780M 4GB/ ARECA 8050/Sony 1080p HDTV [view my complete system specs]
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