AudioMixerSnapshot.TransitionTo doesn't work if called from Monobehavior.Start

While testing in the editor using Unity 5.0.0b12 on Mac.

I'm trying to implement an audio mute / toggle button to set a particular snapshot / state in Start() based on a playerPrefs. The default selected snapshot in the audio mixer is 'volume on'. refreshMixer is called as expected by the ValueChanged event.

With hack == 0, if I run the app once and mute the audio, then re-run the app the audio will not be muted because the TransitionTo call fails (or is ignored).

If hack == 2, it works as expected.

I've submitted a bug report on this. I was wondering if anyone has encountered this issue and if they have a better work around?

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using UnityEngine.UI;
4. using UnityEngine.Audio;
5.  
6. public class musicManager : MonoBehaviour {
7.  
8.     public AudioMixerSnapshot musicOn;
9.     public AudioMixerSnapshot musicOff;
10.     public Toggle musicToggle;
11.     int hack;
12.  
13.     // Use this for initialization
14.     void Start () {
15.         int musicEnabled = PlayerPrefs.GetInt("MusicEnabled", 1);
16.         if (musicEnabled == 1) {
17.             musicToggle.isOn = true;
18.         } else {
19.             musicToggle.isOn = false;
20.         }
21.         hack = 2;
22.     }
23.  
24.     void Update() {
25.         if (hack > 0) {
26.             hack--;
27.             if (hack == 0) {
28.                 refreshMixer();
29.             }
30.         }
31.     }
32.  
33.     public void toggleChanged() {
34.         int musicEnabled;
35.  
36.         if (musicToggle.isOn) {
37.             musicEnabled = 1;
38.         } else {
39.             musicEnabled = 0;
40.         }
41.         PlayerPrefs.SetInt("MusicEnabled", musicEnabled);
42.         PlayerPrefs.Save();
43.         refreshMixer();
44.     }
45.  
46.     void refreshMixer() {
47.         int musicEnabled = PlayerPrefs.GetInt("MusicEnabled", 1);
48.         if (musicEnabled == 1) {
49.             musicOn.TransitionTo(0.2f);
50.         } else {
51.             musicOff.TransitionTo(0.2f);
52.         }
53.     }
54. }
55.  

 

Additionally when targeting iOS, the Xcode build fails:

Code (CSharp):

1. Undefined symbols for architecture armv7:
2.   "RegisterClass_AudioMixerController()", referenced from:
3.       RegisterAllClasses() in RegisterMonoModules.o
4.   "RegisterClass_AudioMixerGroupController()", referenced from:
5.       RegisterAllClasses() in RegisterMonoModules.o
6.   "RegisterClass_AudioMixerSnapshotController()", referenced from:
7.       RegisterAllClasses() in RegisterMonoModules.o
8. ld: symbol(s) not found for architecture armv7
9.  

 

same =

Code (CSharp):

1. Undefined symbols for architecture armv7:
2.   "_OBJC_CLASS_$_ASIdentifierManager", referenced from:
3.       objc-class-ref in DeviceInfo(DeviceInfo.o)
4.   "RegisterClass_AudioMixerController()", referenced from:
5.       RegisterAllClasses() in RegisterMonoModules.o
6.   "UnityPause(bool)", referenced from:
7.       -[UnityAdsUnityWrapper unityAdsDidShow] in UnityAdsUnityWrapper.o
8.       -[UnityAdsUnityWrapper unityAdsDidHide] in UnityAdsUnityWrapper.o
9.   "RegisterClass_AudioMixerGroupController()", referenced from:
10.       RegisterAllClasses() in RegisterMonoModules.o
11.   "RegisterClass_AudioMixerSnapshotController()", referenced from:
12.       RegisterAllClasses() in RegisterMonoModules.o
13. ld: symbol(s) not found for architecture armv7
14. clang: error: linker command failed with exit code 1 (use -v to see invocation