audio interrupt handler may cause crash

[zliuva]

the audio session handler is set as:

AudioSessionInitialize ( NULL, // 'NULL' to use the default (main) run loop NULL, // 'NULL' to use the default run loop mode MyAudioSessionInterruptionListener, // a reference to your interruption callback self // data to pass to your interruption listener callback );

however for an application the audio session will only be initialized once (despite multiple calls to AudioSessionInitialize). thus if the user app creates a new AudioStreamer, the old reference to "self" will become invalid and likely to cause a crash in MyAudioSessionInterruptionListener

one possible solution is to use a global pointer instead of relying on *inClientData

[priyankranka]

Can give me a sample code what needs to be written inside the listener. I am facing the same problem

[zliuva]

a walkaround I used

diff --git a/Classes/AudioStreamer.m b/Classes/AudioStreamer.m
index 6804833..fce0877 100644
--- a/Classes/AudioStreamer.m
+++ b/Classes/AudioStreamer.m
@@ -45,6 +45,8 @@
 NSString * const AS_NETWORK_CONNECTION_FAILED_STRING = @"Network connection failed";
 NSString * const AS_AUDIO_BUFFER_TOO_SMALL_STRING = @"Audio packets are larger than kAQDefaultBufSize.";

+static AudioStreamer *__streamer == nil;
+
 @interface AudioStreamer ()
 @property (readwrite) AudioStreamerState state;

@@ -182,8 +184,7 @@ void MyAudioQueueIsRunningCallback(void *inUserData, AudioQueueRef inAQ, AudioQu
 //
 void MyAudioSessionInterruptionListener(void *inClientData, UInt32 inInterruptionState)
 {
-       AudioStreamer* streamer = (AudioStreamer *)inClientData;
-       [streamer handleInterruptionChangeToState:inInterruptionState];
+       [__streamer handleInterruptionChangeToState:inInterruptionState];
 }
 #endif

@@ -761,6 +762,7 @@ - (void)startInternal
                        &sessionCategory
                );
                AudioSessionSetActive(true);
+               __streamer = self;
        #endif

                // initialize a mutex and condition so that we can block on buffers in use.

[zliuva]

and obviously using this method you should only keep one active AudioStreamer instance

[loretoparisi]

I had the same problem, since I was sharing the streamer object to handle ASStatusChangedNotification in different views. Using the static instance solved this issue. Thanks!

[mattla93]

Same problem here. The crash happen when doing the following actions:

• create a streamer & play
• interrupt streamer
• open application, destory streamer & create, play streamer
• interrupt streamer
• application crash, EXEC_BAD_ACCESS

Solved it with the static object, I think when destroing the Streamer, the Session reports the Interription twice, because the old streamer isn't cleared from the interupption handlers

[Phlibbo]

My app crashed for the same reason, the static object did the trick. Thanks!