GNAudioSourceMic startRecording hangs forever - ios

Question

I'm trying to capture music from an iPhone 4s microphone, using the Gracenote API.
When running on the device, the application gets closed by the OS with failed to launch in time when calling startRecordingon an instance ofGNAudioSourceMic. Find the log below. I copy & pasted most of the code from the GN example app, which is working fine.
There are no issues running it through the simulator.
- (void)mk_initialize
{
AudioSessionInitialize (
NULL,
NULL,
interruptionListenerCallback,
(__bridge void *)(self)
);
#try {
_config = [GNConfig init:GN_CLIENT_ID];
}
#catch (NSException * e) {
NSLog(#"clientId issue");
return;
}
[self.config setProperty: #"debugEnabled"
value: #"1"];
_recognizeFromStream = [GNRecognizeStream gNRecognizeStream:self.config];
_audioConfig = [GNAudioConfig gNAudioConfigWithSampleRate:44100
bytesPerSample:2
numChannels:1];
_audioSourceMicObj = [GNAudioSourceMic gNAudioSourceMic:self.audioConfig];
self.audioSourceMicObj.delegate = self;
NSError *error = nil;
[RecognizeStreamOperation recognizeStreamOperation:self.config];
error = [self.recognizeFromStream startRecognizeSession:op
audioConfig:self.audioConfig];
if (error) {
NSLog(#"ERROR: %#",[error localizedDescription]);
}
[self.audioSourceMicObj startRecording]; // hanging call
[self performSelectorInBackground:#selector(setUpRecognizePCMSession)
withObject:nil];
}
Device Log:
OS Version: iOS 6.1.3 (10B329)
Report Version: 104
Exception Type: 00000020
Exception Codes: 0x000000008badf00d
Highlighted Thread: 0
Application Specific Information:
XXXXXXX failed to launch in time
Elapsed total CPU time (seconds): 3.080 (user 3.080, system 0.000), 15% CPU
Elapsed application CPU time (seconds): 0.527, 3% CPU
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0:
0 libsystem_kernel.dylib 0x397ab0fc __psynch_mutexwait + 24
1 libsystem_c.dylib 0x396f4124 pthread_mutex_lock + 388
2 AudioToolbox 0x30fd54e8 CAMutex::Lock() + 32
3 AudioToolbox 0x3102645c AUConverterBase::Reset(unsigned long, unsigned long) + 48
4 AudioToolbox 0x310df602 AUGenericOutput::Start() + 26
5 AudioToolbox 0x310d1126 AURemoteIO::Start() + 942
6 AudioToolbox 0x31100776 AUMethodStart(void*) + 118
.
.
.

Answer 1

Is another application on your device using the microphone when you try to launch your app? You should make sure to set the audio session category to one that supports recording, and also activate the audio session prior to calling start on the GnAudioSourceMic instance. For example:
NSError *error = nil;
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];
if (error) {
NSLog(#"Error setting audio session category: %d, %#", [error code], [error description]);
}
[[AVAudioSession sharedInstance] setActive:YES error:&error];
if (error) {
NSLog(#"Error activating audio session category: %d, %#", [error code], [error description]);
}