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NateW99
Participating Frequently
October 31, 2019
Answered

Tips for converting 23.97p to 1080i for broadcast

  • October 31, 2019
  • 5 replies
  • 4932 views

Hello! I’m delivering a commercial to several different broadcast outlets. Each has specific broadcast specs but 1080i and 29.97 drop frame seems to be a constant.

 

The project was shot at 23.98p and edited in a 23.98p sequence. I was hoping for some do’s and don’t’s for converting from 23.98p to 29.97i and then exporting so that it looks good on air. 

 

Ive noticed some broadcast commercials play smoothly and cleanly but with others have visible interlacing! Want to make sure my spot does not have visible interlacing when broadcast.

 

Title edited by Mod

 

I’m told upper field first is important. 

 

Shoukd i use maximum render quality setting?

 

One issue I’ve had was when I cut and pasted my 23.98 edit into a 29.97 sequence I had “blank” or kinda half-interlaced frames at the begining and end of all my nested sequences. Seems the drop frame conversion couldn’t handle the nested sequences. I’ve seen online it’s better to drag your entire 24p sequence into the 30i sequence rather than dropping in the clips... can anyone confirm this?

 

Any advice appreciated!!! Thanks!!

This topic has been closed for replies.
Correct answer John V Knowles

You're on the right track. There are indeed issues with pulling in the clips from an edited sequence vs. bringing the edit in as a nest. I can't explain exactly whay, but it's the way Premiere handles the pulldown. I've done several tests on this and nesting avoids the issue. Another thing to keep in mind is cadence – the pattern of repeated frames when pulldown is applied. Changing the frame rate improperly results in bad cadence and the broadcaster may reject it during QC. In summary, here's what's worked for us in the past:

  • Cut in 23.98 and nest in 29.97, export 29.97 = correct cadence
  • Cut in 29.97 (from the start) and export in 29.97 = correct cadence
  • Cut in 23.98 and export directly to 29.97 = incorrect cadence

 

HTH, let me know if you have other questions.

 

JVK

5 replies

N
NateW99Author
Participating Frequently
November 1, 2019

Thanks so much for the responses! Very helpful info. Sounds like dragging my entire 23.98 sequence into the 29.97 sequence is the way to go. Glad to know this is a commonly used workflow. My original sequence does already have a few nested sequences inside it hopefully this won’t cause any issues?

 

Does anyone know why some commercials on tv have visible interlacing while others don’t? Any tips to avoid this? Is it possibly a bitrate issue? Or field order problem?

 

thanks all for the helpful info!

 

 

Averdahl
Community Expert
AverdahlCommunity Expert
Community Expert
November 1, 2019

Does anyone know why some commercials on tv have visible interlacing while others don’t? Any tips to avoid this? Is it possibly a bitrate issue? Or field order problem?

 

I would say lack of knowledge and lack of quality control. I live in PAL land and some TV-series that originated as NTSC and now broadcasted as PAL have some issues as well that look odd. Such as camera pannings/movements that are very stuttery due to incorrect frame rate conversion, while other TV-series that originated as NTSC are have butter smooth pannings/movements.

 

I can see commercials that have text and logos outside both the title safe and action safe area resulting in cropped text and logos in commercials created as PAL and broadcasted as PAL. This is more common in commercials created in HD, delivered as HD and then broadcasted as SD.

R Neil Haugen
R Neil Haugen
Legend
October 31, 2019

Weirdsmobile has the better answer for general working. It's a pretty standard process that is suggested.

 

There are of course methods to go into AfterEffects and ... if you know the process ... control the pull-down method. But the answer given above should work fine. It's used heavily.

 

As always, for pro deliverables ... if you can do a short test export and communicate to the receiving services to see if they would test that in their QC machines, well ... you'd know for certain it is working for you and that service.

 

Neil

Everyone's mileage always varies ...
    S
    salvo34
    Inspiring
    October 31, 2019

    And not to make matters more compclicated, but there's the color space too... full or limited, ,etc... but I don't know why the simple 'export' function doesn't work to simply give something you can send to a so-called 'broadcaster'... whatever that means...

     

     

    S
    salvo34
    Inspiring
    November 1, 2019

    Most of the producers / directors of TV commercials I worked for were hired by an advertising agency and the agency would take care of keeping track of who got what and how the client paid for the air time and what is done with ASCAP and others ( like paying talent residuals etc. ) ... and the post house would give the agency what they needed as per the 'market' they were broadcasting in ( cable, over the air, etc. ).  Stuff that goes through a satelite system usually gets beamed into space via mp4 burst but that is done by that company internally ... some guy at one of those satelite ( giant dishes aimed at mars etc. ) places tried to explain it to me a while back.

     

    but this is a new age, so who knows what is going on now... probably if you round off 29.976 it becomes 29.98 ??

    S
    salvo34
    Inspiring
    October 31, 2019

    Don't be alarmed.. you don't know yet if upper field or lower field first is the best. You don't know if render max is best. You basically have not got your answer, but there is fun stuff to learn about drop frames and pull down frames and all that stuff... which you can test from now until the cows come home, and that's fun too !

     

     

    Averdahl
    Community Expert
    AverdahlCommunity Expert
    Community Expert
    November 1, 2019

    All interlaced HD is Upper Filed First. 

      J
      Community Expert
      John V KnowlesCommunity ExpertCorrect answer
      Community Expert
      October 31, 2019

      You're on the right track. There are indeed issues with pulling in the clips from an edited sequence vs. bringing the edit in as a nest. I can't explain exactly whay, but it's the way Premiere handles the pulldown. I've done several tests on this and nesting avoids the issue. Another thing to keep in mind is cadence – the pattern of repeated frames when pulldown is applied. Changing the frame rate improperly results in bad cadence and the broadcaster may reject it during QC. In summary, here's what's worked for us in the past:

      • Cut in 23.98 and nest in 29.97, export 29.97 = correct cadence
      • Cut in 29.97 (from the start) and export in 29.97 = correct cadence
      • Cut in 23.98 and export directly to 29.97 = incorrect cadence

       

      HTH, let me know if you have other questions.

       

      JVK

      -------------------------------------------------------------------------JVK | Editor/Designer/Software Instructor. Pr, Ae, Ch, Ps, Ai, Id
        chrisw44157881
        chrisw44157881
        Inspiring
        November 1, 2019

        premiere uses an automatic pulldown if you place a 23.976 video into a 29.97 sequence. any direct export will skip that step. i thought you might find that interesting.

        S
        salvo34
        Inspiring
        October 31, 2019

        Your question, unfortunately, is very 'general' in nature and I doubt you'll get much response. But then again, who knows. The basic point you made, that you have various broadcast TV stations asking for specs to be delivered, should be taken out of the question. Deal with one at a time. They all have different specs. Some is because it is NTSC and some are PAL and some are even more different ( Japan, etc. ).

        Plus, most TV stations that we hobbyists deal with are just licensed TV stations, but they don't actually HAVE the equipment to broadcast an electro magetic wave over the air, nor a superstucture to put in on cable. They farm that out to the people who provide THAT service.

        I gave something to a local cable access channel and they use the service ( which is mediacom ) to pump that out via cable. They don't do it themselves. And they were perfectly happy with an mp4 H264 file from me, at 720p, 23.976, progressive... cause it gets converted at the next stage via the mediacom broadcast service.

         

        So, my first suggestion is don't bother genalizing and figure out if it's NTSC or PAL or whatever... and ask a question for that specific spec you are being asked for.

         

        There might be ( and it's a long shot here ) someone who knows how to help you, cause most of the people here do cat videos with their iPhones and put it on YouTube.

         

        : )

         

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