diff --git a/dom/media/fmp4/MP4Demuxer.cpp b/dom/media/fmp4/MP4Demuxer.cpp
index 0a95ac56c86..a21ff213941 100644
--- a/dom/media/fmp4/MP4Demuxer.cpp
+++ b/dom/media/fmp4/MP4Demuxer.cpp
@@ -79,16 +79,22 @@ MP4Demuxer::Init()
   AutoPinned<mp4_demuxer::ResourceStream> stream(mStream);
 
   // Check that we have enough data to read the metadata.
-  if (!mp4_demuxer::MP4Metadata::HasCompleteMetadata(stream)) {
+  MediaByteRange br = mp4_demuxer::MP4Metadata::MetadataRange(stream);
+  if (br.IsNull()) {
     return InitPromise::CreateAndReject(DemuxerFailureReason::WAITING_FOR_DATA, __func__);
   }
 
-  mInitData = mp4_demuxer::MP4Metadata::Metadata(stream);
-  if (!mInitData) {
+  if (!mInitData->SetLength(br.Length(), fallible)) {
     // OOM
     return InitPromise::CreateAndReject(DemuxerFailureReason::DEMUXER_ERROR, __func__);
   }
 
+  size_t size;
+  mStream->ReadAt(br.mStart, mInitData->Elements(), br.Length(), &size);
+  if (size != size_t(br.Length())) {
+    return InitPromise::CreateAndReject(DemuxerFailureReason::DEMUXER_ERROR, __func__);
+  }
+
   nsRefPtr<mp4_demuxer::BufferStream> bufferstream =
     new mp4_demuxer::BufferStream(mInitData);
 
diff --git a/media/libstagefright/binding/MP4Metadata.cpp b/media/libstagefright/binding/MP4Metadata.cpp
index dfa488c3d0a..5effe9f4499 100644
--- a/media/libstagefright/binding/MP4Metadata.cpp
+++ b/media/libstagefright/binding/MP4Metadata.cpp
@@ -287,14 +287,17 @@ MP4Metadata::HasCompleteMetadata(Stream* aSource)
   return parser->HasMetadata();
 }
 
-/*static*/ already_AddRefed<MediaByteBuffer>
-MP4Metadata::Metadata(Stream* aSource)
+/*static*/ mozilla::MediaByteRange
+MP4Metadata::MetadataRange(Stream* aSource)
 {
   // The MoofParser requires a monitor, but we don't need one here.
   mozilla::Monitor monitor("MP4Metadata::HasCompleteMetadata");
   mozilla::MonitorAutoLock mon(monitor);
   auto parser = mozilla::MakeUnique<MoofParser>(aSource, 0, false, &monitor);
-  return parser->Metadata();
+  if (parser->HasMetadata()) {
+    return parser->mInitRange;
+  }
+  return mozilla::MediaByteRange();
 }
 
 } // namespace mp4_demuxer
diff --git a/media/libstagefright/binding/MoofParser.cpp b/media/libstagefright/binding/MoofParser.cpp
index 61a1ec2c720..7bb7d090de0 100644
--- a/media/libstagefright/binding/MoofParser.cpp
+++ b/media/libstagefright/binding/MoofParser.cpp
@@ -148,9 +148,8 @@ MoofParser::BlockingReadNextMoof()
   return false;
 }
 
-void
-MoofParser::ScanForMetadata(mozilla::MediaByteRange& aFtyp,
-                            mozilla::MediaByteRange& aMoov)
+bool
+MoofParser::HasMetadata()
 {
   int64_t length = std::numeric_limits<int64_t>::max();
   mSource->Length(&length);
@@ -158,57 +157,24 @@ MoofParser::ScanForMetadata(mozilla::MediaByteRange& aFtyp,
   byteRanges.AppendElement(MediaByteRange(0, length));
   nsRefPtr<mp4_demuxer::BlockingStream> stream = new BlockingStream(mSource);
 
+  MediaByteRange ftyp;
+  MediaByteRange moov;
   BoxContext context(stream, byteRanges);
   for (Box box(&context, mOffset); box.IsAvailable(); box = box.Next()) {
     if (box.IsType("ftyp")) {
-      aFtyp = box.Range();
+      ftyp = box.Range();
       continue;
     }
     if (box.IsType("moov")) {
-      aMoov = box.Range();
+      moov = box.Range();
       break;
     }
   }
-  mInitRange = aFtyp.Extents(aMoov);
-}
-
-bool
-MoofParser::HasMetadata()
-{
-  MediaByteRange ftyp;
-  MediaByteRange moov;
-  ScanForMetadata(ftyp, moov);
-  return !!ftyp.Length() && !!moov.Length();
-}
-
-already_AddRefed<MediaByteBuffer>
-MoofParser::Metadata()
-{
-  MediaByteRange ftyp;
-  MediaByteRange moov;
-  ScanForMetadata(ftyp, moov);
   if (!ftyp.Length() || !moov.Length()) {
-    return nullptr;
+    return false;
   }
-  nsRefPtr<MediaByteBuffer> metadata = new MediaByteBuffer();
-  if (!metadata->SetLength(ftyp.Length() + moov.Length(), fallible)) {
-    // OOM
-    return nullptr;
-  }
-
-  nsRefPtr<mp4_demuxer::BlockingStream> stream = new BlockingStream(mSource);
-  size_t read;
-  bool rv =
-    stream->ReadAt(ftyp.mStart, metadata->Elements(), ftyp.Length(), &read);
-  if (!rv || read != ftyp.Length()) {
-    return nullptr;
-  }
-  rv =
-    stream->ReadAt(moov.mStart, metadata->Elements() + ftyp.Length(), moov.Length(), &read);
-  if (!rv || read != moov.Length()) {
-    return nullptr;
-  }
-  return metadata.forget();
+  mInitRange = ftyp.Extents(moov);
+  return true;
 }
 
 Interval<Microseconds>
diff --git a/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h b/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
index 28a79bcec75..de9273c2725 100644
--- a/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
+++ b/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
@@ -30,7 +30,7 @@ public:
   ~MP4Metadata();
 
   static bool HasCompleteMetadata(Stream* aSource);
-  static already_AddRefed<MediaByteBuffer> Metadata(Stream* aSource);
+  static mozilla::MediaByteRange MetadataRange(Stream* aSource);
   uint32_t GetNumberTracks(mozilla::TrackInfo::TrackType aType) const;
   mozilla::UniquePtr<mozilla::TrackInfo> GetTrackInfo(mozilla::TrackInfo::TrackType aType,
                                                       size_t aTrackNumber) const;
diff --git a/media/libstagefright/binding/include/mp4_demuxer/MoofParser.h b/media/libstagefright/binding/include/mp4_demuxer/MoofParser.h
index 742e1a72b11..86daead28cd 100644
--- a/media/libstagefright/binding/include/mp4_demuxer/MoofParser.h
+++ b/media/libstagefright/binding/include/mp4_demuxer/MoofParser.h
@@ -228,7 +228,6 @@ public:
 
   bool BlockingReadNextMoof();
   bool HasMetadata();
-  already_AddRefed<MediaByteBuffer> Metadata();
   MediaByteRange FirstCompleteMediaSegment();
   MediaByteRange FirstCompleteMediaHeader();
 
@@ -245,8 +244,6 @@ public:
   Monitor* mMonitor;
   nsTArray<Moof>& Moofs() { mMonitor->AssertCurrentThreadOwns(); return mMoofs; }
 private:
-  void ScanForMetadata(mozilla::MediaByteRange& aFtyp,
-                       mozilla::MediaByteRange& aMoov);
   nsTArray<Moof> mMoofs;
   nsTArray<MediaByteRange> mMediaRanges;
   bool mIsAudio;