Bug 1044498 - Handle overlapped SourceBuffer appends by spinning up a new decoder. Only implemented for WebM so far. r=cajbir

content/media/mediasource/MediaSource.cpp

@@ -210,7 +210,7 @@ MediaSource::AddSourceBuffer(const nsAString& aType, ErrorResult& aRv)
     aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return nullptr;
   }
-  nsRefPtr<SourceBuffer> sourceBuffer = SourceBuffer::Create(this, NS_ConvertUTF16toUTF8(mimeType));
+  nsRefPtr<SourceBuffer> sourceBuffer = new SourceBuffer(this, NS_ConvertUTF16toUTF8(mimeType));
   if (!sourceBuffer) {
     aRv.Throw(NS_ERROR_FAILURE); // XXX need a better error here
     return nullptr;

content/media/mediasource/SourceBuffer.cpp

@@ -26,6 +26,8 @@
 #include "SourceBufferDecoder.h"
 #include "mozilla/Preferences.h"
 
+#include "WebMBufferedParser.h"
+
 struct JSContext;
 class JSObject;
 
@@ -59,11 +61,21 @@ public:
     return false;
   }
 
+  virtual bool ParseStartAndEndTimestamps(const uint8_t* aData, uint32_t aLength,
+                                          double& aStart, double& aEnd)
+  {
+    return false;
+  }
+
   static ContainerParser* CreateForMIMEType(const nsACString& aType);
 };
 
 class WebMContainerParser : public ContainerParser {
 public:
+  WebMContainerParser()
+    : mTimecodeScale(0)
+  {}
+
   bool IsInitSegmentPresent(const uint8_t* aData, uint32_t aLength)
   {
     ContainerParser::IsInitSegmentPresent(aData, aLength);
@@ -83,6 +95,37 @@ public:
     }
     return false;
   }
+
+  virtual bool ParseStartAndEndTimestamps(const uint8_t* aData, uint32_t aLength,
+                                          double& aStart, double& aEnd)
+  {
+    // XXX: This is overly primitive, needs to collect data as it's appended
+    // to the SB and handle, rather than assuming everything is present in a
+    // single aData segment.
+
+    WebMBufferedParser parser(0);
+    if (mTimecodeScale != 0) {
+      parser.SetTimecodeScale(mTimecodeScale);
+    }
+
+    nsTArray<WebMTimeDataOffset> mapping;
+    ReentrantMonitor dummy("dummy");
+    parser.Append(aData, aLength, mapping, dummy);
+
+    mTimecodeScale = parser.GetTimecodeScale();
+
+    if (mapping.IsEmpty()) {
+      return false;
+    }
+
+    static const double NS_PER_S = 1e9;
+    aStart = mapping[0].mTimecode / NS_PER_S;
+    aEnd = mapping.LastElement().mTimecode / NS_PER_S;
+    return true;
+  }
+
+private:
+  uint32_t mTimecodeScale;
 };
 
 class MP4ContainerParser : public ContainerParser {
@@ -352,6 +395,7 @@ SourceBuffer::SourceBuffer(MediaSource* aMediaSource, const nsACString& aType)
   : DOMEventTargetHelper(aMediaSource->GetParentObject())
   , mMediaSource(aMediaSource)
   , mType(aType)
+  , mLastParsedTimestamp(UnspecifiedNaN<double>())
   , mAppendWindowStart(0)
   , mAppendWindowEnd(PositiveInfinity<double>())
   , mTimestampOffset(0)
@@ -366,13 +410,6 @@ SourceBuffer::SourceBuffer(MediaSource* aMediaSource, const nsACString& aType)
   InitNewDecoder();
 }
 
-already_AddRefed<SourceBuffer>
-SourceBuffer::Create(MediaSource* aMediaSource, const nsACString& aType)
-{
-  nsRefPtr<SourceBuffer> sourceBuffer = new SourceBuffer(aMediaSource, aType);
-  return sourceBuffer.forget();
-}
-
 SourceBuffer::~SourceBuffer()
 {
   MOZ_ASSERT(NS_IsMainThread());
@@ -504,6 +541,26 @@ SourceBuffer::AppendData(const uint8_t* aData, uint32_t aLength, ErrorResult& aR
     aRv.Throw(NS_ERROR_FAILURE);
     return;
   }
+  double start, end;
+  if (mParser->ParseStartAndEndTimestamps(aData, aLength, start, end)) {
+    if (start <= mLastParsedTimestamp) {
+      // This data is earlier in the timeline than data we have already
+      // processed, so we must create a new decoder to handle the decoding.
+      DiscardDecoder();
+
+      // If we've got a decoder here, it's not initialized, so we can use it
+      // rather than creating a new one.
+      if (!InitNewDecoder()) {
+        aRv.Throw(NS_ERROR_FAILURE); // XXX: Review error handling.
+        return;
+      }
+      MSE_DEBUG("SourceBuffer(%p)::AppendData: Decoder marked as initialized (%f, %f).",
+                this, start, end);
+      mDecoderInitialized = true;
+    }
+    mLastParsedTimestamp = end;
+    MSE_DEBUG("SourceBuffer(%p)::AppendData: Segment start=%f end=%f", this, start, end);
+  }
   // XXX: For future reference: NDA call must run on the main thread.
   mDecoder->NotifyDataArrived(reinterpret_cast<const char*>(aData),
                               aLength,
@@ -520,7 +577,7 @@ SourceBuffer::AppendData(const uint8_t* aData, uint32_t aLength, ErrorResult& aR
   const uint32_t evict_threshold = 75 * (1 << 20);
   bool evicted = mDecoder->GetResource()->EvictData(evict_threshold);
   if (evicted) {
-    MSE_DEBUG("SourceBuffer(%p)::AppendBuffer Evict; current buffered start=%f",
+    MSE_DEBUG("SourceBuffer(%p)::AppendData Evict; current buffered start=%f",
               this, GetBufferedStart());
 
     // We notify that we've evicted from the time range 0 through to

content/media/mediasource/SourceBuffer.h

@@ -89,7 +89,7 @@ public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(SourceBuffer, DOMEventTargetHelper)
 
-  static already_AddRefed<SourceBuffer> Create(MediaSource* aMediaSource, const nsACString& aType);
+  SourceBuffer(MediaSource* aMediaSource, const nsACString& aType);
 
   MediaSource* GetParentObject() const;
 
@@ -114,8 +114,6 @@ public:
 private:
   ~SourceBuffer();
 
-  SourceBuffer(MediaSource* aMediaSource, const nsACString& aType);
-
   friend class AsyncEventRunner<SourceBuffer>;
   void DispatchSimpleEvent(const char* aName);
   void QueueAsyncSimpleEvent(const char* aName);
@@ -141,6 +139,8 @@ private:
 
   nsAutoPtr<ContainerParser> mParser;
 
+  double mLastParsedTimestamp;
+
   nsRefPtr<SourceBufferDecoder> mDecoder;
   nsTArray<nsRefPtr<SourceBufferDecoder>> mDecoders;
 

content/media/webm/WebMReader.cpp

@@ -1026,52 +1026,45 @@ nsresult WebMReader::Seek(int64_t aTarget, int64_t aStartTime, int64_t aEndTime,
 
 nsresult WebMReader::GetBuffered(dom::TimeRanges* aBuffered, int64_t aStartTime)
 {
-  MediaResource* resource = mDecoder->GetResource();
-
-  uint64_t timecodeScale;
-  if (!mContext || nestegg_tstamp_scale(mContext, &timecodeScale) == -1) {
-    return NS_OK;
+  if (aBuffered->Length() != 0) {
+    return NS_ERROR_FAILURE;
   }
 
+  MediaResource* resource = mDecoder->GetResource();
+
   // Special case completely cached files.  This also handles local files.
-  bool isFullyCached = resource->IsDataCachedToEndOfResource(0);
-  if (isFullyCached) {
+  if (mContext && resource->IsDataCachedToEndOfResource(0)) {
     uint64_t duration = 0;
     if (nestegg_duration(mContext, &duration) == 0) {
       aBuffered->Add(0, duration / NS_PER_S);
+      return NS_OK;
     }
   }
 
-  uint32_t bufferedLength = 0;
-  aBuffered->GetLength(&bufferedLength);
-
   // Either we the file is not fully cached, or we couldn't find a duration in
   // the WebM bitstream.
-  if (!isFullyCached || !bufferedLength) {
-    MediaResource* resource = mDecoder->GetResource();
-    nsTArray<MediaByteRange> ranges;
-    nsresult res = resource->GetCachedRanges(ranges);
-    NS_ENSURE_SUCCESS(res, res);
+  nsTArray<MediaByteRange> ranges;
+  nsresult res = resource->GetCachedRanges(ranges);
+  NS_ENSURE_SUCCESS(res, res);
 
-    for (uint32_t index = 0; index < ranges.Length(); index++) {
-      uint64_t start, end;
-      bool rv = mBufferedState->CalculateBufferedForRange(ranges[index].mStart,
-                                                          ranges[index].mEnd,
-                                                          &start, &end);
-      if (rv) {
-        double startTime = start * timecodeScale / NS_PER_S - aStartTime;
-        double endTime = end * timecodeScale / NS_PER_S - aStartTime;
-        // If this range extends to the end of the file, the true end time
-        // is the file's duration.
-        if (resource->IsDataCachedToEndOfResource(ranges[index].mStart)) {
-          uint64_t duration = 0;
-          if (nestegg_duration(mContext, &duration) == 0) {
-            endTime = duration / NS_PER_S;
-          }
+  for (uint32_t index = 0; index < ranges.Length(); index++) {
+    uint64_t start, end;
+    bool rv = mBufferedState->CalculateBufferedForRange(ranges[index].mStart,
+                                                        ranges[index].mEnd,
+                                                        &start, &end);
+    if (rv) {
+      double startTime = start / NS_PER_S - aStartTime;
+      double endTime = end / NS_PER_S - aStartTime;
+      // If this range extends to the end of the file, the true end time
+      // is the file's duration.
+      if (mContext && resource->IsDataCachedToEndOfResource(ranges[index].mStart)) {
+        uint64_t duration = 0;
+        if (nestegg_duration(mContext, &duration) == 0) {
+          endTime = duration / NS_PER_S;
         }
-
-        aBuffered->Add(startTime, endTime);
       }
+
+      aBuffered->Add(startTime, endTime);
     }
   }
 

content/media/webm/moz.build

@@ -5,6 +5,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 EXPORTS += [
+    'WebMBufferedParser.h',
     'WebMDecoder.h',
     'WebMReader.h',
 ]