AVAudioSession and MFi Hearing Aids

Hi,

We are developing an audio streaming app. Recently we found that our app does not play audio streams when a user’s iPhone connects to Signia NX, which is an MFi hearing aid.


The root cause was we called `setPreferredIOBufferDuration:error` of AVAudioSession and set a larger IO buffer. When a larger duration is set, the console give us error messages like


kAudioUnitErr_TooManyFramesToProcess : inFramesToProcess=5645, mMaxFramesPerSlice=4096


We tried to remove the line of code that calls `setPreferredIOBufferDuration:error` and it works. However, our AVAudioSession setting looks fine when connecting to all other types of bluetooth headsets, speakers and car systems that we have, it merely does not work with Signia NX.


We have not tried other MFi hearing aid models, since Signia NX is the only model available in Taiwan right now. All others are not imported to my country yet.


We would like to know


1. If Signia NX is the only one requires a smaller IO buffer, or all MFi heading aids do? What’s a recommended buffer setting?

2. Is there anything else that we need to care about while working with audio playback on MFi hearing aids?


Thanks!

Replies

We're having the same issue. Have you been able to solve the problem?