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I have to export an MXF file for a program that have certain limitations:

Conform to SMPTE 274M, “1920 x 1080 Scanning with no visible video impairment such as blocking errors or pixelization artefacts. Luminance and color difference signals must not exceed the bounds of legal gamut. Video technical standards are fully detailed in ITU-R BT.709.5.

For the video levels, sync and blanking must be in accordance with EBU recommendations, the component video levels must not exceed 700mV ±3% for the luminance channel and ±350 mV for the color difference channels. No excursions below black level can be tolerated in the luminance, never below 0mV.

I marked in bold the parts where I'm not confident with.

Let's say that I have already exported an intermediate ProRes or DNxHD file and I want it to be used as input in the timeline for the new export as the definitive MXF.

How can I meet that requests with Premiere ? I saw under the Color Correction filter category some plugins like Video Limiter and Broadcast Colors but the amount of tweaks given seems poor to me and I can't find values expressed in mV ..

Premiere Effects

Premiere Effects II

What I am missing ?

My request is how to do it with Premiere.. and if is possible do the same also with ffmpeg, thanks!!

I'm already working in rec 709 environment:

MediaInfo says:

Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
matrix_coefficients_Origina : BT.709

This is my ProRes input.

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2 Answers 2

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To legalize video with the Video Limiter:

  • Set the Reduction Axis to Chroma and Luma.
  • Set the Signal Minimum to 0% (=0 mV).
  • Set the Signal Maximum to 103% (=700 mV + 3%).

The rest of the settings may take some experimentation to find something that looks good for your project.

I strongly recommend double checking you are within limits with a good gamut visualization. I'm partial to the Tektronix split diamond display, but other test equipment vendors have other good versions. If you are going to be delivering a lot of files, a file-based QC system will also be able to check for legal colors and some can even do the correction.

Something to take in to consideration, depending on the broadcaster you are delivering to, they may not enforce the gamut requirements all that strictly. I know that most in the US don't, unless you are severely and noticeably out of gamut.

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  • Thanks for your reply, I'm delivering to an european broadcaster, hence the pal setting I was trying to use in the broadcast colors filter. For what concern the other settings I have idea how to set them. I'm not part of the creative process of making the movie. I had only to join audio and video plus check the correct levels before delivery the final file. I also can't at all use hardware tools, all I can do is software with my workstation. Can you extend your reply trying to match also the other settings like: Reduction Method (i guess i have to use compress all) and Tonal Range Definition ?
    – user3450548
    Commented Jul 7, 2017 at 9:37
  • Out of curiosity, what Broadcast Colors effect do? Should I use both Video Limiter and Broadcast Colors or just only the Limiter to obtain my purpose ? thanks!
    – user3450548
    Commented Jul 7, 2017 at 9:39
  • The Broadcast Colors effect has been deprecated. It was for NTSC and PAL gamuts and probably won't give you good results with HD. As far as I know for the other Video Limiter settings, there aren't any specific settings to guarantee legal colors. You'll need to experiment based on the look of your project. There are software "meters" out there that are better than using a waveform monitor, but you can use a waveform in parade mode or isolating individual channels to confirm legality.
    – Michael Liebman
    Commented Jul 7, 2017 at 20:29
  • Interesting the consideration for Broadcast Colors, I will avoid using it then. My job this time was to do some post on titles and graphics but as I said I'm not part of the creative process that's why I'm looking for a file based checker or software to limit automatically everything inside the requested values. Is not something that I want to do frame per frame manually.. that's just crazy. I have to conform something like 25 episodes each time of a series, you can understand that what I set inside that parameters must be certain and not a thing that I can experiment each time :\
    – user3450548
    Commented Jul 8, 2017 at 9:18
  • It definitely isn't something you need to do frame by frame, but blind application of legalizers can dramatically affect the overall look. For delivering that much material, consider looking at commercial products like Tektronix Aurora, Interra Baton, or Telestream Vidchecker. One of those is likely to be the software that the broadcaster will be using to QC what you deliver.
    – Michael Liebman
    Commented Jul 8, 2017 at 17:51
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As per pg 12 of this BBC document,

TECHNICAL STANDARDS FOR DELIVERY OF TELEVISION PROGRAMMES TO BBC

The limits of signal levels are defined by reference to a nominal black level and a nominal white level. Black level comprises R, G and B all at zero (or 0% or 0mV) and white level is all three components at 100 % or 700mV.

In a picture signal, each component is allowed to range between 0 and 100% (or 0mV and 700mV). This equates to digital sample levels 16 and 235 (8-bit systems) or 64 and 940 (10 bit systems).

You don't mention which encoder you wish to use, but my fallback answer is that if the input to ffmpeg is studio/limited range i.e. 16-235 luma and BT.709, so will the output.

You can use either the waveform (visual) or signalstats (text) filter to check for out-of-range values.

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  • I updated the answer with my orginal prores input (bt.709 indeed). At this point maybe is better split the ffmpeg topic in a new question that I will link here.
    – user3450548
    Commented Jul 7, 2017 at 9:57
  • This is the link to the new question: video.stackexchange.com/questions/21878/…
    – user3450548
    Commented Jul 8, 2017 at 0:14

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