Bug 1525507 - P1. Don't trust mp4 container to determine if a VP9 frame is a keyframe. r=bryce

Similar to what we do for H264 and for vp9 in webm, we parse the VP9 bytestream and check if a frame is a keyframe there instead.

Differential Revision: https://phabricator.services.mozilla.com/D18790

--HG--
extra : moz-landing-system : lando

dom/media/mp4/MP4Demuxer.cpp

@@ -14,9 +14,12 @@
 #include "BufferStream.h"
 #include "H264.h"
 #include "Index.h"
+#include "MP4Decoder.h"
 #include "MP4Metadata.h"
 #include "MoofParser.h"
 #include "ResourceStream.h"
+#include "VPXDecoder.h"
+#include "mozilla/Span.h"
 #include "mozilla/StaticPrefs.h"
 #include "mozilla/Telemetry.h"
 #include "nsAutoPtr.h"
@@ -71,7 +74,11 @@ class MP4TrackDemuxer : public MediaTrackDemuxer,
   RefPtr<MediaRawData> mQueuedSample;
   bool mNeedReIndex;
   bool mNeedSPSForTelemetry;
-  bool mIsH264 = false;
+  enum CodecType {
+    kH264,
+    kVP9,
+    kOther
+  } mType = kOther;
 };
 
 // Returns true if no SPS was found and search for it should continue.
@@ -350,9 +357,8 @@ MP4TrackDemuxer::MP4TrackDemuxer(MediaResource* aResource,
 
   VideoInfo* videoInfo = mInfo->GetAsVideoInfo();
   // Collect telemetry from h264 AVCC SPS.
-  if (videoInfo && (mInfo->mMimeType.EqualsLiteral("video/mp4") ||
-                    mInfo->mMimeType.EqualsLiteral("video/avc"))) {
-    mIsH264 = true;
+  if (videoInfo && MP4Decoder::IsH264(mInfo->mMimeType)) {
+    mType = kH264;
     RefPtr<MediaByteBuffer> extraData = videoInfo->mExtraData;
     mNeedSPSForTelemetry = AccumulateSPSTelemetry(extraData);
     SPSData spsdata;
@@ -365,6 +371,9 @@ MP4TrackDemuxer::MP4TrackDemuxer(MediaResource* aResource,
       videoInfo->mDisplay.height = spsdata.display_height;
     }
   } else {
+    if (videoInfo && VPXDecoder::IsVP9(mInfo->mMimeType)) {
+      mType = kVP9;
+    }
     // No SPS to be found.
     mNeedSPSForTelemetry = false;
   }
@@ -422,7 +431,7 @@ already_AddRefed<MediaRawData> MP4TrackDemuxer::GetNextSample() {
   }
   if (mInfo->GetAsVideoInfo()) {
     sample->mExtraData = mInfo->GetAsVideoInfo()->mExtraData;
-    if (mIsH264 && !sample->mCrypto.IsEncrypted()) {
+    if (mType == kH264 && !sample->mCrypto.IsEncrypted()) {
       H264::FrameType type = H264::GetFrameType(sample);
       switch (type) {
         case H264::FrameType::I_FRAME:
@@ -455,6 +464,20 @@ already_AddRefed<MediaRawData> MP4TrackDemuxer::GetNextSample() {
           // TODO: make demuxer errors non-fatal.
           break;
       }
+    } else if (mType == kVP9 && !sample->mCrypto.IsEncrypted()) {
+      bool keyframe = VPXDecoder::IsKeyframe(
+          MakeSpan<const uint8_t>(sample->Data(), sample->Size()),
+          VPXDecoder::Codec::VP9);
+      if (sample->mKeyframe != keyframe) {
+        NS_WARNING(nsPrintfCString(
+                       "Frame incorrectly marked as %skeyframe "
+                       "@ pts:%" PRId64 " dur:%" PRId64 " dts:%" PRId64,
+                       keyframe ? "" : "non-", sample->mTime.ToMicroseconds(),
+                       sample->mDuration.ToMicroseconds(),
+                       sample->mTimecode.ToMicroseconds())
+                       .get());
+        sample->mKeyframe = keyframe;
+      }
     }
   }
 
@@ -491,7 +514,7 @@ RefPtr<MP4TrackDemuxer::SamplesPromise> MP4TrackDemuxer::GetSamples(
   }
   for (const auto& sample : samples->mSamples) {
     // Collect telemetry from h264 Annex B SPS.
-    if (mNeedSPSForTelemetry && mIsH264 && AnnexB::IsAVCC(sample)) {
+    if (mNeedSPSForTelemetry && mType == kH264 && AnnexB::IsAVCC(sample)) {
       RefPtr<MediaByteBuffer> extradata = H264::ExtractExtraData(sample);
       if (H264::HasSPS(extradata)) {
         RefPtr<MediaByteBuffer> extradata = H264::ExtractExtraData(sample);