AVMIDIPlayer DLSBankManager::AddBank: Bank load failed - midi

Question

When I use AVMIDIPlayer to play a MusicSequence with only one note message. Most of times it works fine but sometimes it has no sound and logged as below:
DLSBankManager::AddBank: Bank load failed
Error Domain=com.apple.coreaudio.avfaudio Code=-10871 "(null)"
It works well on iOS9, but when i test it on iOS10 it runs into this issue.
I'm sure that the sf2 sound bank file url is set properly.
I paste the code as below:
func playAVMIDIPlayerPreview(_ musicSequence:MusicSequence) {
guard let bankURL = Bundle.main.url(forResource: "FluidR3 GM2-2", withExtension: "sf2") else {
fatalError("soundbank file not found.")
}
var status = OSStatus(noErr)
var data:Unmanaged<CFData>?
status = MusicSequenceFileCreateData (musicSequence,
MusicSequenceFileTypeID.midiType,
MusicSequenceFileFlags.eraseFile,
480, &data)
if status != OSStatus(noErr) {
print("bad status \(status)")
}
if let md = data {
let midiData = md.takeUnretainedValue() as Data
do {
try self.midiPlayerPreview = AVMIDIPlayer(data: midiData, soundBankURL: bankURL)
} catch let error as NSError {
print("Error \(error)")
}
data?.release()
self.midiPlayerPreview?.play({ () -> Void in
self.midiPlayerPreview = nil
self.musicSequencePreview = nil
})
}
}
The error is occur on this line:
try self.midiPlayerPreview = AVMIDIPlayer(data: midiData, soundBankURL: bankURL)

Answer 1

Try setting the global variable errno to 0 errno = 0 before loading the soundfont with
try self.midiPlayerPreview = AVMIDIPlayer(data: midiData, soundBankURL: bankURL)
We experienced the same issue and at the same time this one.
So we tried to apply the fix of the other issue to this one and it just worked.