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Forums Broadcasting Broadcast Legal Luminance: Black bars at zero% IRE

  • Broadcast Legal Luminance: Black bars at zero% IRE

  • clyde villegas

    October 16, 2017 at 9:11 pm

    I created a video for broadcast to 4:3 NTSC TV but my original video was shot in 16:9 so I squeezed the video in to fill 4:3 (letter boxing). Everything in the video is within 7.5 to 100% IRE broadcast standard. However, my black bars on top and bottom (letterbox) of the video is at zero% IRE. Do the black bars also need to be at 7.5% IRE for my video to be considered broadcast legal? Thanks! God bless!

    ut in omnibus glorificetur Deus

  • Tom Matthies

    October 20, 2017 at 5:31 pm

    For broadcasting, yes they should be. Is this airing as true NTSC (analog) video or on a digital transmission? It it’s just running on a monitor or on cable, you can probably get away with the 0% levels. If it’s for broadcast on a digital TV station, that may be another story. Where will your videos be used?

    Not my monkeys. Not my circus.

  • clyde villegas

    October 23, 2017 at 6:46 am

    Thank you very much, Tom. Yes, it’s for analog NTSC.

    I’m using Premiere CC 2015’s waveform monitor. This morning, someone told me that CC 2015’s waveform monitor is “digital.” He said if it shows 0% IRE, “analog” stations will read that as 7.5% IRE. So if it shows 0% IRE in Premiere 2015’s waveform, that is perfectly ok for analog NTSC broadcast. Is that correct?

    ut in omnibus glorificetur Deus

  • Tom Matthies

    October 31, 2017 at 11:35 pm

    It will probably be OK. I don’t use Premiere but many applications are smart enough to add the 7.5% setup to an analog output. The control panel on some output cards (adapters/converters) will ask if you want to add setup on the output.n It just depends on how you are getting your finished video out-file based or direct output.

    Not my monkeys. Not my circus.

  • Chris Clementson

    July 24, 2018 at 11:16 am

    Replying to this old thread …

    Make awfully darn sure your bars are not digital 0. Zero is reserved for sync and is sure to wreak havoc if it is in your video. To be on the safe side I would make them digital 16 which equals 0 IRE in “studio swing”.

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