Hi there,
bit of a noob question here, but can somebody confirm that spatializing multichannel tracks is possible?
I have the following scenario. FMOD is used as the sound engine for Unity to build an iOS app. Using the app on an iPhone with AirPods Pro, the head motion should spatialize the audio content of the app. This is working for files that are stereo or mono, but whenever I use a multichannel file (12 channels, exported from Nuendo as 7.1.4) the spatializing does not work. Would be great, if anyone has an idea or could point me in the right direction on what could be wrong with this approach.
Thx, and everyone a happy new year.
There is currently an issue where multichannel files beyond a certain channel count will collapse own to mono. We are currently investigating when this change happened and how to fix it.
Hi Richard,
thank you for the reply. As mentioned in my post, we are working on an app right now which would be ready for release by the end of next month. Do you have any idea if there will be a fix in the foreseeable future or is it a bigger challenge and do you know if the bug will occur in general with a channel count more than stereo or does it only affect 5.1, 7.1, or only 7.1.4 and will it make any difference if we would choose to use the object spatializer over the default spatializer.
Thanks in advance,
David
It doesn’t look like it can be fixed within the current version. It should be available in the next major version release of FMOD Studio. Saying that, I would like to hear what you mean by the spatializer not working as most spatializers (FMOD Spatializer and FMOD Object Spatializer included) will collapse any input down to mono first before it is run through the effect.
Every audio file contains a certain number of “channels”. An audio file with one channel is mono. An audio file with two channels is stereo. Most of the time these channels are assigned to specific speakers such as left, right, subwoofer, etc. But once FMOD encounters an audio file with more channels than expected it will simply mix them all down into a single channel.
The current maximum number of channels is 12 to correspond to the 7.1.4 surround setup (7 surround speakers, 1 subwoofer, 4 ceiling speakers).
So the next major version release would be version 3 right? Since the latest version is 2.02 I am guessing that it will not happen any time soon, correct?
To be honest I am not sure if most Spatializers will collapse multichannel files to mono. Isn’t the Object Spatializer supposed to work with platform-specific technologies like Dolby Atmos for example? And wouldn’t that mean that it should be capable to handle an ADM BWF Atmos export, which could simply be a multichannel 7.1.4 file with some meta data including the exact position and movement of the sound objects in that file?
We are actually very happy with using FMOD so far and thought that since it supports multichannel audio that there should be a way to somehow use our multichannel exported files within FMOD and still make use of spatialization. Anyway, thank you Richard for taking the time. If you do have any more information for us on that topic we would really appreciate it. Just to be clear am I understanding you correctly, that it is only possible to make use of the Spatializer, or the Object Spatializer Plugins by using mono files within FMOD?
Thanks in advance and have a good day.
That’s correct, the next major version is FMOD Studio 2.03.00. We unfortunately can’t give much information out on when it can be released.
For the Object spatializer, it collapses all input down to mono before spatializing. For the FMOD spatializer it depends on envelopment - far enough away it will collapse to mono then spatialize but if you’re near it then the speakers are respected. If the channel count of the input is greater than the number of channels the FMOD spatializer uses (as specified in the project settings) then it will collapse the audio down.
All spatializers will work with any number of channel inputs, it will do automatic downmixing into one channel before it spatializes in certain circumstances listed above.
Taking another look at your question, it’s actually more to do with the new Apple AirPod Pros and their built-in spatializer features. I mistakenly thought this was just a multi-channel file issue.
Could you please let me know what behaviour you are wishing to happen? For example, are you wanting to have relative channels panned left/right?
Could you try again with 5.1 or 7.1 and make sure Studio is outputting that 5.1 or 7.1 in the edit > preferences > build settings? Ensure System::setSoftwareFormat has been configured for that speaker mode, then finally configure the OS to receive multichannel: https://fmod.com/resources/documentation-api?version=2.02&page=platforms-ios.html#multichannel-output