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Let's talk B-format/Ambisonic support

Looking for your collective guidance and wisdom here. Currently there are ways to work with B-format/Ambisonics audio sources within Dolby Atmos, but it can be somewhat complex. 

What is the ideal workflow - from ingest to output - for working with B-format/Ambisonics within Atmos? 

What flavors of B-format ingest do we need to support? 

How do you foresee working with higher order Ambisonics (HOA)?

Looking forward to hearing your thoughts!

Sheldon Radford


I'm an ambisonics neophyte, so not the most informed person to answer the topic.  

However it seems clear that there are two standard 1st order ambisonics formats which are widely supported by other tools, and it seems wise to allow input from them:

- FuMa

- Ambix  

Easiest would be to have a mode where such sounds, placed on a quad track, could simply be fed into the mix directly.  Three-axis rotation would be important to implement, so sounds could be oriented.


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Thanks Jeremiah, this is helpful. Any thoughts on the need for support HOA as an input source? Or are most of the needs centered around 4-ch B-format?

Sheldon Radford


With higher order you get more angular resolution, but truly how much material is available in these formats?  (And there is the complexity of various channel ordering and weighting schemes.. oh, the complexity multiplies.)

FB360 Spatial Workstation is doing a partial implementation of second-order, adding resolution to horizontal panning.  Adding support for 2nd order would potentially allow (if implemented decently) material in TBE format to be more readily brought in to Atmos.  Some folks might like / use this.  

(and BTW tonight at 6:30pm there is an event at Pyramind in SF where the guys from TBE / Facebook 360 Spatial Workstation will be doing a panel.  In case it's of interest!)

direct support of FOA files (FuMa or AmbiX selectable) on 4-channel tracks in PT to be rotated would be essential to make use of FOA field recordings on events.
TBE does a nice job with this, something similar would be nice.


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Another thing: It seems that Google is drafting a new RFC in which they aim for (up to) 3rd order ambisonics plus a head-locked static stereo track. I guess they will roll this out for Youtube.

So, support as an output format of the Dolby Atmos for VR system for this would be awesome.


Sorry to dredge this post up from a couple months ago, but just a couple thoughts on my end: - Being able to work with 1st-3rd order ambisonics would be great. Decoding them to 7.1 plus stereo overhead for the bed could achieve a similar result, but if there was a way to just work with them natively, and to choose whether whether it was headtracked or not, would be fantastic. - I know it's been mentioned before, but I figured I would bring it up again especially now since Facebook allows for second order ambisonic mixes to be played directly through their player. Being able to transcode the final print master as a second or third order ambisonic mix through the Encoder would be fantastic. Even better would be to somehow playback an ambisonic rendering directly in Protools. I know that would bring up some tricky technical issues, and would be damn near impossible to get that to happen in realtime since you would have to encode to B-Format in the renderer presumably, then have a decoder built into the pipeline at some point to render the binaural output with realtime headtracking, but hey-- a fella can dream, right? The most pressing matter for me right now would be getting second and third order transcodes possible from a print master. Being able to post second order ambisonic mixes that were mixed with Atmos on Facebook would be pretty great. As Red Bull mentioned too, Google's third order ambisonic support rumors still abound so being future proof for that would be great.

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Thanks Tom, good info. So two main topics here:

1) Being able to output additional formats, including HOA, via the Dolby Transcoder app

2) Being able to ingest B-format (or HOA) source files into an Atmos project

Do I have these right?

Both are considered important, from our perspective. At present we're looking at ways to bring pre-recorded Ambisonics tracks (e.g., ambiences recorded on site) and allow you to manipulate and mix these with objects and produce an Atmos output. On the right track?

Supporting alternate output formats is also useful, and on the list.


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Nailed it, Sheldon!

Again, apologies for being late to the party!

With products like the Sennheiser Ambeo VR and Rode On-Camera Ambisonic mic hitting the market, I feel like more and more content creators are going to be handing off ambisonics tracks recorded on location, so being able to bring in A/B-Format content (with head tracking) into the Atmos environment would be HUGE!

Honestly, I think having the ability to route a quad track in pro tools to say - Atmos sends 125-128 would be a great start.  Having rotational control would be nice, but honestly just having the ability to enable/disable head tracking would be enough for me for VR.  The FB360 environment does do a nice job of dealing with B-Format Tracks in a simple manner (Source Roll, Source Pitch, Source Yaw, Envelopment) w/ support for both FuMa and AmbiX

I realize this would be a TON of work on y'alls end as there would need to be a quad version of the pro tools panner plugin (of sorts) as well as some way to decode the B-Format within the renderer/monitor apps.  At least by using 4 of the object sends, it would get it from PT to the renderer.

However, the silver lining perhaps is that I could also see this functionality being beneficial to traditional theatrical Atmos mixers as well.  I know myself and at least one other mixer in town have been using ambisonic ambiences in our surround mixes.  I am sure others are as well.

Right now, I would use the Surround Zone 2 Plugin to fold it into the 7.1 bed.  However, having the ability to decode the B-format content inside the Atmos environment across the array, would add another layer of immersiveness for that perfect ambisonic track.

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