media: In low delay mode, do not accumulate frames earlier than the start time.

media/renderers/video_renderer_impl_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/debug/stack_trace.h"
@@ skipping 28 matching lines @@
 
 ACTION_P(RunClosure, closure) {
   closure.Run();
 }
 
 MATCHER_P(HasTimestamp, ms, "") {
   *result_listener << "has timestamp " << arg->timestamp().InMilliseconds();
   return arg->timestamp().InMilliseconds() == ms;
 }
 
-class VideoRendererImplTest : public testing::TestWithParam<bool> {
+class VideoRendererImplTest
+    : public testing::TestWithParam<bool /* new_video_renderer */> {
  public:
   VideoRendererImplTest()
       : tick_clock_(new base::SimpleTestTickClock()),
         decoder_(new MockVideoDecoder()),
         demuxer_stream_(DemuxerStream::VIDEO) {
     ScopedVector<VideoDecoder> decoders;
     decoders.push_back(decoder_);
 
     null_video_sink_.reset(new NullVideoSink(
         false, base::TimeDelta::FromSecondsD(1.0 / 60),
@@ skipping 420 matching lines @@
   Initialize();
   QueueFrames("50 60 70 80 90");
 
   EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(60)));
   EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH));
   StartPlayingFrom(61);
   Destroy();
 }
 
 TEST_P(VideoRendererImplTest, StartPlayingFrom_LowDelay) {
-  // In low-delay mode only one frame is required to finish preroll.
+  // In low-delay mode only one frame is required to finish preroll. But frames
+  // prior to the start time will not be used.
   InitializeWithLowDelay(true);
-  QueueFrames("0");
+  QueueFrames("0 10");
 
+  EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(10)));
   // Expect some amount of have enough/nothing due to only requiring one frame.
-  EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(0)));
   EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_ENOUGH))
       .Times(AnyNumber());
   EXPECT_CALL(mock_cb_, BufferingStateChange(BUFFERING_HAVE_NOTHING))
       .Times(AnyNumber());

[xhwang, 2015/07/21 20:30:26]

When using the old rendering path, we declare HAVE_NOTHING whenever we run out
of frame, which could be pretty common in low delay mode in tests. In real life
this could also happen. Maybe we should have some grace period to declare
HAVE_NOTHING in low delay mode.

Or, when are we gonna drop old rendering path altogether? It's such a pain to
keep them both in our code...

[DaleCurtis, 2015/07/21 21:16:50]

I was planning to delete the old path this week as soon as I can find time :)

-  StartPlayingFrom(0);
+  StartPlayingFrom(10);
 
-  QueueFrames("10");
+  QueueFrames("20");
   SatisfyPendingRead();
 
   renderer_->OnTimeStateChanged(true);
   time_source_.StartTicking();
 
   WaitableMessageLoopEvent event;
-  EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(10)))
+  EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(20)))
       .WillOnce(RunClosure(event.GetClosure()));
-  AdvanceTimeInMs(10);
+  AdvanceTimeInMs(20);
   event.RunAndWait();
 
   Destroy();
 }
 
 // Verify that a late decoder response doesn't break invariants in the renderer.
 TEST_P(VideoRendererImplTest, DestroyDuringOutstandingRead) {
   Initialize();
   QueueFrames("0 10 20 30");
   EXPECT_CALL(mock_cb_, FrameReceived(HasTimestamp(0)));
@@ skipping 224 matching lines @@
 }
 
 INSTANTIATE_TEST_CASE_P(OldVideoRenderer,
                         VideoRendererImplTest,
                         testing::Values(false));
 INSTANTIATE_TEST_CASE_P(NewVideoRenderer,
                         VideoRendererImplTest,
                         testing::Values(true));
 
 }  // namespace media