Atmos: from Nuendo ADM to MP4 7.1.4 or higher + binaural

Nuendo
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I’m aware that several threads already deal with this subject in a partial or non-updated way. But I’d like to start afresh on the subject. I’m running Nuendo 12 on a PC. I try to export an AMD of the first 5 minutes of an Atmos project, as a test, and I discover some difficulties. I understand that the Dolby Atmos renderer can be used, on a PC, not to replace Nuendo’s internal Renderer (you’d need a second PC), but, in stand-alone mode, to check the rendering from an ADM file, yes, but then to produce the MP4 for consumer listening. The Dolby Atmos renderer is offered free of charge for 90 days. That gives us plenty of time to try it out.

  1. First observation: Nuendo, as stated elsewhere, does not share the channel configuration with Dolby. It inverts the surround sides and rears, because it follows the Microsoft plan (which is obviously a mistake, but perhaps a programming constraint at Steinberg, I don’t know). Let’s hope for a correction for Nuendo 13. I think it’s that which produces this message in the Dolby Atmos renderer: the Inputs configuration doesn’t match the Master. It’s a question of correcting the inversion, as I did for my UAD Apollo X16 on the monitoring side. Time wasted, but it’s not difficult, as we’re all familiar with it by now.

  2. Second observation, more personal: I don’t understand whether the binaural version (as opposed to a version for a physical system) is included in Nuendo’s ADM or whether something else needs to be created for this purpose. It’s all a blur. Not one document tells us: hey, you want to produce a file readable on a physical multichannel system + a binaural one, then do this or that. Nothing. Those who know will answer here. We thank them.

  3. Third observation on the listening check: the track synchro is a bit delirious. There’s a gap. I’d say between the groups (narration, sound effects, FX, music). Why is this? Is it the ADM export in Nuendo, or the Dolby Atmos renderer configuration?

I have other points, but answers to these would be a good starting point.

Note that I’m also placing this thread on the excellent Dolby Atmos forum

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As far as I understand it, you don’t need to define a playback system. Atmos translates the configuration to the authored file. One file can be used on a binaural configuration too.

3

Yes, you’re right. Dolby has just confirmed this point : “Binaural distance model metadata is written to the ADM BWF Atmos master file. This is used when the audio is encoded as AC4-IMS for various streaming services. There is no specific ADM BWF that needs to be created for this purpose. The binaural output available when the downmix is set as binaural and exported as a mixdown is for QC reference only. This is also available as an output from the Dolby Atmos Renderer application.”

3 Likes
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In fact, this is very poorly documented. I suspect that very few users know that the binaural metadata is only used with AC-4 IMS. This means that 99.9% of users can ignore the corresponding settings in the renderer.

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I think that’s it. So it’s simpler.