Bug 1261900: [webm] Use block duration if known. r=kinetik

dom/media/webm/NesteggPacketHolder.h

@@ -19,7 +19,12 @@ namespace mozilla {
 class NesteggPacketHolder {
 public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(NesteggPacketHolder)
-  NesteggPacketHolder() : mPacket(nullptr), mOffset(-1), mTimestamp(-1), mIsKeyframe(false) {}
+  NesteggPacketHolder()
+    : mPacket(nullptr)
+    , mOffset(-1)
+    , mTimestamp(-1)
+    , mDuration(-1)
+    , mIsKeyframe(false) {}
 
   bool Init(nestegg_packet* aPacket, int64_t aOffset, unsigned aTrack, bool aIsKeyframe)
   {
@@ -36,12 +41,17 @@ public:
     mTrack = aTrack;
     mIsKeyframe = aIsKeyframe;
 
+    uint64_t duration_ns;
+    if (!nestegg_packet_duration(aPacket, &duration_ns)) {
+      mDuration = duration_ns / 1000;
+    }
     return true;
   }
 
   nestegg_packet* Packet() { MOZ_ASSERT(IsInitialized()); return mPacket; }
   int64_t Offset() { MOZ_ASSERT(IsInitialized()); return mOffset; }
   int64_t Timestamp() { MOZ_ASSERT(IsInitialized()); return mTimestamp; }
+  int64_t Duration() { MOZ_ASSERT(IsInitialized()); return mDuration; }
   unsigned Track() { MOZ_ASSERT(IsInitialized()); return mTrack; }
   bool IsKeyframe() { MOZ_ASSERT(IsInitialized()); return mIsKeyframe; }
 
@@ -62,6 +72,9 @@ private:
   // Packet presentation timestamp in microseconds.
   int64_t mTimestamp;
 
+  // Packet duration in microseconds; -1 if unknown or retrieval failed.
+  int64_t mDuration;
+
   // Track ID.
   unsigned mTrack;
 

dom/media/webm/WebMDemuxer.cpp

@@ -510,8 +510,9 @@ WebMDemuxer::GetNextPacket(TrackInfo::TrackType aType, MediaRawDataQueue *aSampl
     return false;
   }
   int64_t tstamp = holder->Timestamp();
+  int64_t duration = holder->Duration();
 
-  // The end time of this frame is the start time of the next frame.  Fetch
+  // The end time of this frame is the start time of the next frame. Fetch
   // the timestamp of the next packet for this track.  If we've reached the
   // end of the resource, use the file's duration as the end time of this
   // video frame.
@@ -521,6 +522,8 @@ WebMDemuxer::GetNextPacket(TrackInfo::TrackType aType, MediaRawDataQueue *aSampl
     if (next_holder) {
       next_tstamp = next_holder->Timestamp();
       PushAudioPacket(next_holder);
+    } else if (duration >= 0) {
+      next_tstamp = tstamp + duration;
     } else if (!mIsMediaSource ||
                (mIsMediaSource && mLastAudioFrameTime.isSome())) {
       next_tstamp = tstamp;
@@ -534,6 +537,8 @@ WebMDemuxer::GetNextPacket(TrackInfo::TrackType aType, MediaRawDataQueue *aSampl
     if (next_holder) {
       next_tstamp = next_holder->Timestamp();
       PushVideoPacket(next_holder);
+    } else if (duration >= 0) {
+      next_tstamp = tstamp + duration;
     } else if (!mIsMediaSource ||
                (mIsMediaSource && mLastVideoFrameTime.isSome())) {
       next_tstamp = tstamp;