--- a/dom/media/AudioStream.cpp
+++ b/dom/media/AudioStream.cpp
@@ -314,17 +314,17 @@ template <>
 struct ToCubebFormat<AUDIO_FORMAT_S16> {
   static const cubeb_sample_format value = CUBEB_SAMPLE_S16NE;
 };
 
 nsresult
 AudioStream::Init(uint32_t aNumChannels, uint32_t aRate,
                   const dom::AudioChannel aAudioChannel)
 {
-  mStartTime = TimeStamp::Now();
+  auto startTime = TimeStamp::Now();
   mIsFirst = CubebUtils::GetFirstStream();
 
   if (!CubebUtils::GetCubebContext()) {
     return NS_ERROR_FAILURE;
   }
 
   LOG("%s channels: %d, rate: %d", __FUNCTION__, aNumChannels, aRate);
   mInRate = mOutRate = aRate;
@@ -346,23 +346,23 @@ AudioStream::Init(uint32_t aNumChannels,
   if (params.stream_type == CUBEB_STREAM_TYPE_MAX) {
     return NS_ERROR_INVALID_ARG;
   }
 #endif
 
   params.format = ToCubebFormat<AUDIO_OUTPUT_FORMAT>::value;
   mAudioClock.Init();
 
-  return OpenCubeb(params);
+  return OpenCubeb(params, startTime);
 }
 
 // This code used to live inside AudioStream::Init(), but on Mac (others?)
 // it has been known to take 300-800 (or even 8500) ms to execute(!)
 nsresult
-AudioStream::OpenCubeb(cubeb_stream_params &aParams)
+AudioStream::OpenCubeb(cubeb_stream_params &aParams, TimeStamp aStartTime)
 {
   cubeb* cubebContext = CubebUtils::GetCubebContext();
   if (!cubebContext) {
     NS_WARNING("Can't get cubeb context!");
     MonitorAutoLock mon(mMonitor);
     mState = AudioStream::ERRORED;
     return NS_ERROR_FAILURE;
   }
@@ -385,23 +385,21 @@ AudioStream::OpenCubeb(cubeb_stream_para
       mState = ERRORED;
       NS_WARNING(nsPrintfCString("AudioStream::OpenCubeb() %p failed to init cubeb", this).get());
       return NS_ERROR_FAILURE;
     }
   }
 
   mState = INITIALIZED;
 
-  if (!mStartTime.IsNull()) {
-    TimeDuration timeDelta = TimeStamp::Now() - mStartTime;
-    LOG("creation time %sfirst: %u ms", mIsFirst ? "" : "not ",
-        (uint32_t) timeDelta.ToMilliseconds());
-    Telemetry::Accumulate(mIsFirst ? Telemetry::AUDIOSTREAM_FIRST_OPEN_MS :
-        Telemetry::AUDIOSTREAM_LATER_OPEN_MS, timeDelta.ToMilliseconds());
-  }
+  TimeDuration timeDelta = TimeStamp::Now() - aStartTime;
+  LOG("creation time %sfirst: %u ms", mIsFirst ? "" : "not ",
+      (uint32_t) timeDelta.ToMilliseconds());
+  Telemetry::Accumulate(mIsFirst ? Telemetry::AUDIOSTREAM_FIRST_OPEN_MS :
+      Telemetry::AUDIOSTREAM_LATER_OPEN_MS, timeDelta.ToMilliseconds());
 
   return NS_OK;
 }
 
 void
 AudioStream::SetVolume(double aVolume)
 {
   MOZ_ASSERT(aVolume >= 0.0 && aVolume <= 1.0, "Invalid volume");

--- a/dom/media/AudioStream.h
+++ b/dom/media/AudioStream.h
@@ -308,17 +308,17 @@ protected:
 
   // Return the position, measured in audio frames played since the stream was
   // opened, of the audio hardware, not adjusted for the changes of playback
   // rate or underrun frames.
   // Caller must own the monitor.
   int64_t GetPositionInFramesUnlocked();
 
 private:
-  nsresult OpenCubeb(cubeb_stream_params &aParams);
+  nsresult OpenCubeb(cubeb_stream_params &aParams, TimeStamp aStartTime);
 
   static long DataCallback_S(cubeb_stream*, void* aThis,
                              const void* /* aInputBuffer */, void* aOutputBuffer,
                              long aFrames)
   {
     return static_cast<AudioStream*>(aThis)->DataCallback(aOutputBuffer, aFrames);
   }
 
@@ -347,19 +347,16 @@ private:
   uint32_t mInRate;
   // Output rate in Hz (characteristic of the playback rate)
   uint32_t mOutRate;
   uint32_t mChannels;
   uint32_t mOutChannels;
   AudioClock mAudioClock;
   soundtouch::SoundTouch* mTimeStretcher;
 
-  // Stream start time for stream open delay telemetry.
-  TimeStamp mStartTime;
-
   // Output file for dumping audio
   FILE* mDumpFile;
 
   // Owning reference to a cubeb_stream.
   UniquePtr<cubeb_stream, CubebDestroyPolicy> mCubebStream;
 
   enum StreamState {
     INITIALIZED, // Initialized, playback has not begun.