Forum Post

VidarG (Storyline Studios) asked a question.

February 24, 2022 at 8:42 AM
Is it possible to add a true peak limiter to the ADM file?
I'm delivering a movie for Netflix. They want the true peak of the ADM file to be at -2.
I add a true peak limiter off -2.3 to all my beds and object. But there's no way of limiting the sum?
  • 4 answers

  • Poorna Srikar Maremanda (/linktr.ee/srikarmps/)

    Once the mix is finished, Create once master VCA and Connect all your beds & objects to that ..... Run an offline loudness analysis inside DAPS and accordingly bring down your fader, your exported ADM will then automatically qualify Netflix specs

    • VidarG (Storyline Studios)

      I talked to Netflix after writing this. And the loudness measurments you get in DAPS is a bit missleading. Because it’s not for your ADM file. But for your 5.1 re-renderer.
      There is no way to actually measure the TP values of your ADM file. So they recommended just TP limiting your beds and objects at -2.3 out of pro tools. and that guaranted your ADM file would be within -2db tp.

  • Poorna Srikar Maremanda (/linktr.ee/srikarmps/)

    Yes, all the specs are all based on 5.1 as the standard ITU reference. So don't worry ...there is no misleading here, if your TP is -2 in a 5.1 re-render then you are already in a safe zone for a 7.1.4 ! Presumably, it will be around -3 to -2.5 when decoded to 7.1.4 by an AVR using this ADM. It's very similar to increasing loudness in downmixes .... when channels get summed ...You have to think in reverse ....Well, we know that whenever 5.1 is read at -18 LUFS then its 2.0 downmix will be automatically around -16 to -14. Similarly, the Actual Atmos mixes are in reality lie around -20 to -22 LUFS when decoded by an AVR. Hence measuring 5.1 loudness gives us a good idea as a standard for both downmixes and up-mixes. Summing it all up when your TP read as -2 in 5.1, then it will be approx -0.8 to -1 in 2.0 downmix depending on the attenuation you choose in Lo/Ro encoding, logically in a similar way for 7.1.4 it will be around -3 to -3.2 and for 9.1.6 it will be around -4.5 and for 11.1.8 it will be around -5 ( near-field small commercial Dolby Atmos Cinema Theater venues min spk config )

    There is no as such Limiting on ADM since it's only a metadata conveying carriage with audio for AVRs that will decide how to decode the mix on the user end based on his available spk config and his / her remote will have the dynamic range controls anyways and different modes like Movies, Music, Game, etc. Hence it's not the best option to integrate a limiter functionally into ADM, doesn't make sense. Unfortunately, manufacturers decide how they want to decode the incoming Atmos mix and even worse compress the DRC sometimes with their custom-tuned speaker drivers in a bid for optimizing the mix for that speaker mode, best examples are Phones and Tablets.

    So do not worry ....You are already in the safe zone

    Best wishes
    Expand Post

Don't see what you're looking for?

You must be logged in to submit new topics