I'm implementing a web application which works with video sources with SMPTE time codes printed on it. Often the SMPTE and media time differs, my understanding of the reason based on what I have read is:

  • Video is shot at a regular frame rate (ex: 24 or 30)
  • Video is broadcasted on 23.976 or 29.97 frame rate due to NTSC historic reasons when it started broadcasting color (I understand the reasoning)

However, a few things are not clear for me:

  • It seems that Today is common to already shot in 23.976 or 29.97 cameras, so why would still this difference exist?
  • The current TVs and streaming services don't have the NTSC limitations anymore
  • NTSC is not the only standard around, European PAL doesn't have this issue, for example

Now, on my application the user needs to manually select the frame rate, based on my understanding above it doesn't make sense to automatically detect from the video file, because the difference happens when the recorded frame rate is different from the broadcasted one, therefore, it needs to select the broadcasted frame rate, not the video file.

Most of the videos on my application are from streaming services, those streaming services run worldwide, with all sort of different formats... so all of these are confusing me to have a fully understanding of the SMPTE time codes.

  • You might want to research drop-frame timecode.
    – Matt
    Apr 15, 2021 at 19:36
  • I doubt asking about why those framerates are still in use will help you with your practical problem. There are probably many systems that only work with specific frame rates, so it's problematic to stop supporting them. Standards that supercede NTSC also support those rates anyway. so you will continue to see a variety of frame rates for many more decades.
    – Matt
    Apr 15, 2021 at 19:42
  • I know about drop-frame @Matt, but I don't see how these relate to my question.
    – dfranca
    Apr 16, 2021 at 7:41
  • My question is not about supporting them or not, My question is because some of my understandings of SMPTE timecodes have been challenged with the points I have mentioned, and I want to know if my understanding and assumptions are correct or if I am missing something.
    – dfranca
    Apr 16, 2021 at 7:44


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