--- a/dom/media/GraphDriver.cpp
+++ b/dom/media/GraphDriver.cpp
@@ -556,18 +556,18 @@ StreamAndPromiseForOperation::StreamAndP
   , mOperation(aOperation)
 {
   // MOZ_ASSERT(aPromise);
 }
 
 AudioCallbackDriver::AudioCallbackDriver(MediaStreamGraphImpl* aGraphImpl)
   : GraphDriver(aGraphImpl)
   , mOuputChannels(mGraphImpl->AudioChannelCount())
-  , mScratchBuffer(mOuputChannels)
-  , mBuffer(mOuputChannels)
+  , mScratchBuffer(std::max<uint32_t>(1, mOuputChannels))
+  , mBuffer(std::max<uint32_t>(1, mOuputChannels))
   , mSampleRate(0)
   , mInputChannels(1)
   , mIterationDurationMS(MEDIA_GRAPH_TARGET_PERIOD_MS)
   , mStarted(false)
   , mAudioInput(nullptr)
   , mAddedMixer(false)
   , mInCallback(false)
   , mMicrophoneActive(false)