--- a/dom/media/platforms/agnostic/VPXDecoder.cpp
+++ b/dom/media/platforms/agnostic/VPXDecoder.cpp
@@ -83,16 +83,17 @@ VPXDecoder::~VPXDecoder()
 {
   MOZ_COUNT_DTOR(VPXDecoder);
 }
 
 void
 VPXDecoder::Shutdown()
 {
   vpx_codec_destroy(&mVPX);
+  vpx_codec_destroy(&mVPXAlpha);
 }
 
 RefPtr<MediaDataDecoder::InitPromise>
 VPXDecoder::Init()
 {
   if (NS_FAILED(InitContext(&mVPX, mInfo, mCodec))) {
     return VPXDecoder::InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_FATAL_ERR,
                                                     __func__);