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pulck
Participating Frequently
October 4, 2020
Question

Video Limiter producing illegal broadcast levels

  • October 4, 2020
  • 3 replies
  • 2358 views

I'm currently involved in a Avid-offline/Premiere-online workflow and we are consistently running into the same problem with the Premiere Video Limiter.

 

Captions and subtitles generated in Premiere are producing illegal sub-blacks and excessive-whites. This is despite setting the Premiere Video Limiter to conservative values. They look fine when viewed in the Premiere scope, but are illegal when they are viewed during the QC process.

 

Although I'm not involved in the QC process, this is what I'm being told is happening: Premiere is tagging our exports as "full range". This means that even if Premiere thinks it's producing legal values, when the exported file is viewed elsewhere, these legal values expand out and become illegal.

 

I admit I don't fully understand this, but does anyone here have experience with this problem and can advise me how to avoid Premiere producing these "full range" exports?

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3 replies

chrisw44157881
chrisw44157881
Inspiring
October 4, 2020

when in doubt, use the tried and true method. one adjustment layer set to luminosity with levels 16-235

and another adjustment layer on top set to 'color' with levels 0-240.

this preset has been downloaded over a thousand times!

https://f1.creativecow.net/10774/premiere-pro-cc-20152-broadcast-safe-preset

P
pulckAuthor
Participating Frequently
October 5, 2020

Thanks, @chrisw44157881. However, the problem is not that levels are illegal in Premiere, but that they are illegal after export. So I'm not sure that swapping one sort of adjustment layer for another is going to make any difference.

 

Just to clarify: in Premiere levels are looking fine and dandy. But once the file is exported file it is being tagged as "full range" and this is pushing what look like legal levels inside Premiere to illegal levels when viewed during QC.

chrisw44157881
chrisw44157881
Inspiring
October 5, 2020

perhaps the MXF/codec: AVC-Intra 100 is being exported full range because premiere interprets Prores as video levels, but AVC-100 as full. Try exporting from media encoder to Prores and using another encoder to get from Prores to AVC-100. Adobe Media encoder doesn't have a way to manually set legal vs full afaik. and Adobe's limiter plugin may have a bug on export, so see if manually clipping it makes a change too. I know shutter encoder supports AS-11 format in AVC- intra100.

    R Neil Haugen
    R Neil Haugen
    Legend
    October 4, 2020

    I'm not getting it in the 14.x versions, but in some earlier ones I could at times get a problem with super-darks and ultra-whites with text, normally if any sharpening was applied in the image.

     

    Also, are they applying the Limiter preset to the clip, to an adjustment layer over the sequence, or in the Export dialog's Effects tab?

     

    Neil

    Everyone's mileage always varies ...
    P
    pulckAuthor
    Participating Frequently
    October 4, 2020

    I'm pretty sure that the limiter is being applied on an adjustment layer. Is that not advisable? 

    R Neil Haugen
    R Neil Haugen
    Legend
    October 4, 2020

    I was just curious how they were doing it. I would suggest also trying the option in the Export dialog itself.

     

    Neil

    Everyone's mileage always varies ...
    R Neil Haugen
    R Neil Haugen
    Legend
    October 4, 2020

    Which format/codecs are you using? Perhaps as it's an Avid/Premiere workflow some form of DNxHD/R?

     

    There are some Lumetri presets in the Lumetri Presets/Technical folder that are for legal to full or full to legal conversions. The LUTs used are found in the Program/Package folder for Premiere, Lumetri/LUTs/Legacy. The full to legal ones are all "FullToSMPTE ..." and in 8, 10, and 12 bit versions listed there in the name in the folder.

     

    You could try adding Full to Legal in Export options dialog Effects tab, and see if that clears QC.

     

     

     

     

    Neil

    Everyone's mileage always varies ...
      P
      pulckAuthor
      Participating Frequently
      October 4, 2020

      Thanks, Neil.

       

      In the most recent delivery that failed QC, the files ingested into Premiere were Quicktime/codec: ProRes. Then the final master exported from Premiere was an MXF/codec: AVC-Intra 100.

       

      I'm not the Premiere editor (I do the Avid offlines) but I'm trying to help get to the bottom of what's causing the problem. So I'll ask the editor what settings he's using in his Export dialog.

      R Neil Haugen
      R Neil Haugen
      Legend
      October 4, 2020

      I modded my earlier answer to add the location for the Full/Legal and Legal/Full LUTs.

       

      Neil

      Everyone's mileage always varies ...
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