Missing buffered attribute for <video>/<audio>

BUG=16056
TEST=LayoutTests/media/video-buffered.html

The current implementation of the buffered attribute for <video> and <audio>
is broken. There are several problems around this attribute:

1. We don't have any caching on disk, so we only keep a recent range of bytes
   close to current playback position.
2. WebKit reports buffered as one range (0, max_time_buffered). But we only
   cache a short partial range which doesn't start with 0. The correct
   implementation is a list of ranges buffered. But this has to go into WebKit
   first.
3. We don't have an accurate mapping between byte offset < - > timestamp.

So the current implementation is to lie about what we have buffered. We always
say we have buffered everything before the current download position. And we
only report one range. The calculation of time is also based on scaling the
duration with current buffered bytes.

Review URL: http://codereview.chromium.org/160300

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22087 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 64 insertions, 2 deletions

diff --git a/media/base/mock_filters.h b/media/base/mock_filters.h
index d3546c4..533ced7 100644
--- a/media/base/mock_filters.h
+++ b/media/base/mock_filters.h
@@ -342,6 +342,18 @@ ACTION_P2(SetDuration, filter, duration) {
   filter->host()->SetDuration(duration);
 }
 
+// Helper gmock action that calls SetTotalBytes() on behalf of the provided
+// filter.
+ACTION_P2(SetTotalBytes, filter, bytes) {
+  filter->host()->SetTotalBytes(bytes);
+}
+
+// Helper gmock action that calls SetBufferedBytes() on behalf of the provided
+// filter.
+ACTION_P2(SetBufferedBytes, filter, bytes) {
+  filter->host()->SetBufferedBytes(bytes);
+}
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_MOCK_FILTERS_H_
diff --git a/media/base/pipeline_impl.cc b/media/base/pipeline_impl.cc
index 05ee62e..cc1c3b2 100644
--- a/media/base/pipeline_impl.cc
+++ b/media/base/pipeline_impl.cc
@@ -211,7 +211,22 @@ base::TimeDelta PipelineImpl::GetCurrentTime() const {
 
 base::TimeDelta PipelineImpl::GetBufferedTime() const {
   AutoLock auto_lock(lock_);
-  return buffered_time_;
+
+  // If buffered time was set, we report that value directly.
+  if (buffered_time_.ToInternalValue() > 0)
+    return buffered_time_;
+
+  // If buffered time was not set, we use duration and buffered bytes to
+  // estimate the buffered time.
+  // TODO(hclam): The estimation is based on linear interpolation which is
+  // not accurate enough. We should find a better way to estimate the value.
+  if (total_bytes_ == 0)
+    return base::TimeDelta();
+
+  double ratio = static_cast<double>(buffered_bytes_);
+  ratio /= total_bytes_;
+  return base::TimeDelta::FromMilliseconds(
+      static_cast<int64>(duration_.InMilliseconds() * ratio));
 }
 
 base::TimeDelta PipelineImpl::GetDuration() const {
diff --git a/media/base/pipeline_impl_unittest.cc b/media/base/pipeline_impl_unittest.cc
index 068b095..6400049 100644
--- a/media/base/pipeline_impl_unittest.cc
+++ b/media/base/pipeline_impl_unittest.cc
@@ -20,6 +20,16 @@ using ::testing::NotNull;
 using ::testing::Return;
 using ::testing::StrictMock;
 
+namespace {
+
+// Total bytes of the data source.
+const int kTotalBytes = 1024;
+
+// Buffered bytes of the data source.
+const int kBufferedBytes = 1024;
+
+}  // namespace
+
 namespace media {
 
 // Used for setting expectations on pipeline callbacks.  Using a StrictMock
@@ -70,7 +80,9 @@ class PipelineImplTest : public ::testing::Test {
   // Sets up expectations to allow the data source to initialize.
   void InitializeDataSource() {
     EXPECT_CALL(*mocks_->data_source(), Initialize("", NotNull()))
-        .WillOnce(Invoke(&RunFilterCallback));
+        .WillOnce(DoAll(SetTotalBytes(mocks_->data_source(), kTotalBytes),
+                        SetBufferedBytes(mocks_->data_source(), kBufferedBytes),
+                        Invoke(&RunFilterCallback)));
     EXPECT_CALL(*mocks_->data_source(), SetPlaybackRate(0.0f));
     EXPECT_CALL(*mocks_->data_source(), Seek(base::TimeDelta(), NotNull()))
         .WillOnce(Invoke(&RunFilterCallback));
@@ -404,4 +416,27 @@ TEST_F(PipelineImplTest, SetVolume) {
   pipeline_->SetVolume(expected);
 }
 
+TEST_F(PipelineImplTest, Properties) { 
+  scoped_refptr<StrictMock<MockDemuxerStream> > stream =
+      new StrictMock<MockDemuxerStream>("video/x-foo");
+  MockDemuxerStreamVector streams;
+  streams.push_back(stream);
+
+  InitializeDataSource();
+  base::TimeDelta kDuration = base::TimeDelta::FromSeconds(100);
+  InitializeDemuxer(&streams, kDuration);
+  InitializeVideoDecoder(stream);
+  InitializeVideoRenderer();
+
+  InitializePipeline();
+  EXPECT_TRUE(pipeline_->IsInitialized());
+  EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
+  EXPECT_EQ(kDuration.ToInternalValue(),
+            pipeline_->GetDuration().ToInternalValue());
+  EXPECT_EQ(kTotalBytes, pipeline_->GetTotalBytes());
+  EXPECT_EQ(kBufferedBytes, pipeline_->GetBufferedBytes());
+  EXPECT_EQ(kDuration.ToInternalValue(),
+            pipeline_->GetBufferedTime().ToInternalValue());
+}
+
 }  // namespace media