--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -2668,17 +2668,16 @@ ShutdownState::Enter()
   master->mVideoQueueListener.Disconnect();
   master->mMetadataManager.Disconnect();
   master->mOnMediaNotSeekable.Disconnect();
 
   // Disconnect canonicals and mirrors before shutting down our task queue.
   master->mBuffered.DisconnectIfConnected();
   master->mExplicitDuration.DisconnectIfConnected();
   master->mPlayState.DisconnectIfConnected();
-  master->mNextPlayState.DisconnectIfConnected();
   master->mVolume.DisconnectIfConnected();
   master->mPreservesPitch.DisconnectIfConnected();
   master->mLooping.DisconnectIfConnected();
   master->mSameOriginMedia.DisconnectIfConnected();
   master->mMediaPrincipalHandle.DisconnectIfConnected();
   master->mPlaybackBytesPerSecond.DisconnectIfConnected();
   master->mPlaybackRateReliable.DisconnectIfConnected();
   master->mDecoderPosition.DisconnectIfConnected();
@@ -2730,17 +2729,16 @@ MediaDecoderStateMachine::MediaDecoderSt
   mVideoDecodeSuspendTimer(mTaskQueue),
   mOutputStreamManager(new OutputStreamManager()),
   mResource(aDecoder->GetResource()),
   mVideoDecodeMode(VideoDecodeMode::Normal),
   mIsMSE(aDecoder->IsMSE()),
   INIT_MIRROR(mBuffered, TimeIntervals()),
   INIT_MIRROR(mExplicitDuration, Maybe<double>()),
   INIT_MIRROR(mPlayState, MediaDecoder::PLAY_STATE_LOADING),
-  INIT_MIRROR(mNextPlayState, MediaDecoder::PLAY_STATE_PAUSED),
   INIT_MIRROR(mVolume, 1.0),
   INIT_MIRROR(mPreservesPitch, true),
   INIT_MIRROR(mLooping, false),
   INIT_MIRROR(mSameOriginMedia, false),
   INIT_MIRROR(mMediaPrincipalHandle, PRINCIPAL_HANDLE_NONE),
   INIT_MIRROR(mPlaybackBytesPerSecond, 0.0),
   INIT_MIRROR(mPlaybackRateReliable, true),
   INIT_MIRROR(mDecoderPosition, 0),
@@ -2777,17 +2775,16 @@ void
 MediaDecoderStateMachine::InitializationTask(MediaDecoder* aDecoder)
 {
   MOZ_ASSERT(OnTaskQueue());
 
   // Connect mirrors.
   mBuffered.Connect(mReader->CanonicalBuffered());
   mExplicitDuration.Connect(aDecoder->CanonicalExplicitDuration());
   mPlayState.Connect(aDecoder->CanonicalPlayState());
-  mNextPlayState.Connect(aDecoder->CanonicalNextPlayState());
   mVolume.Connect(aDecoder->CanonicalVolume());
   mPreservesPitch.Connect(aDecoder->CanonicalPreservesPitch());
   mLooping.Connect(aDecoder->CanonicalLooping());
   mSameOriginMedia.Connect(aDecoder->CanonicalSameOriginMedia());
   mMediaPrincipalHandle.Connect(aDecoder->CanonicalMediaPrincipalHandle());
   mPlaybackBytesPerSecond.Connect(aDecoder->CanonicalPlaybackBytesPerSecond());
   mPlaybackRateReliable.Connect(aDecoder->CanonicalPlaybackRateReliable());
   mDecoderPosition.Connect(aDecoder->CanonicalDecoderPosition());

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -668,19 +668,18 @@ private:
 
 private:
   // The buffered range. Mirrored from the decoder thread.
   Mirror<media::TimeIntervals> mBuffered;
 
   // The duration explicitly set by JS, mirrored from the main thread.
   Mirror<Maybe<double>> mExplicitDuration;
 
-  // The current play state and next play state, mirrored from the main thread.
+  // The current play state, mirrored from the main thread.
   Mirror<MediaDecoder::PlayState> mPlayState;
-  Mirror<MediaDecoder::PlayState> mNextPlayState;
 
   // Volume of playback. 0.0 = muted. 1.0 = full volume.
   Mirror<double> mVolume;
 
   // Pitch preservation for the playback rate.
   Mirror<bool> mPreservesPitch;
 
   // Whether to seek back to the start of the media resource