--- a/content/media/GraphDriver.cpp
+++ b/content/media/GraphDriver.cpp
@@ -459,17 +459,17 @@ OfflineClockDriver::WakeUp()
   MOZ_ASSERT(false, "An offline graph should not have to wake up.");
 }
 
 AsyncCubebTask::AsyncCubebTask(AudioCallbackDriver* aDriver, AsyncCubebOperation aOperation)
   : mDriver(aDriver),
     mOperation(aOperation),
     mShutdownGrip(aDriver->GraphImpl())
 {
-  MOZ_ASSERT(mDriver->mAudioStream || aOperation == INIT, "No audio stream !");
+  NS_WARN_IF_FALSE(mDriver->mAudioStream || aOperation == INIT, "No audio stream !");
 }
 
 AsyncCubebTask::~AsyncCubebTask()
 {
 }
 
 NS_IMETHODIMP
 AsyncCubebTask::Run()