Move underflow threshold limits out of the video renderer.

media/renderers/video_renderer_impl.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 "media/renderers/video_renderer_impl.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
@@ skipping 172 matching lines @@
 
   // The number of milliseconds to idle when we do not have anything to do.
   // Nothing special about the value, other than we're being more OS-friendly
   // than sleeping for 1 millisecond.
   //
   // TODO(scherkus): switch to pure event-driven frame timing instead of this
   // kIdleTimeDelta business http://crbug.com/106874
   const base::TimeDelta kIdleTimeDelta =
       base::TimeDelta::FromMilliseconds(10);
 
-  // If we have no frames and haven't painted any frame for certain amount of
-  // time, declare BUFFERING_HAVE_NOTHING.
-  const base::TimeDelta kTimeToDeclareHaveNothing =
-      base::TimeDelta::FromSeconds(3);
-
   for (;;) {
     base::AutoLock auto_lock(lock_);
 
     // Thread exit condition.
     if (is_shutting_down_)
       return;
 
     // Remain idle as long as we're not playing.
     if (state_ != kPlaying || buffering_state_ != BUFFERING_HAVE_ENOUGH) {
       UpdateStatsAndWait_Locked(kIdleTimeDelta);
       continue;
     }
 
     base::TimeTicks now = tick_clock_->NowTicks();
 
     // Remain idle until we have the next frame ready for rendering.
     if (ready_frames_.empty()) {
+      base::TimeDelta wait_time = kIdleTimeDelta;
       if (received_end_of_stream_) {
         if (!rendered_end_of_stream_) {
           rendered_end_of_stream_ = true;
           task_runner_->PostTask(FROM_HERE, ended_cb_);
         }
-      } else if (!last_painted_time_.is_null() &&
-                 now - last_painted_time_ >= kTimeToDeclareHaveNothing) {
+      } else if (now >= latest_possible_paint_time_) {
+        // Declare HAVE_NOTHING if we don't have another frame by the time we
+        // are ready to paint the next one.
         buffering_state_ = BUFFERING_HAVE_NOTHING;
         task_runner_->PostTask(
             FROM_HERE, base::Bind(buffering_state_cb_, BUFFERING_HAVE_NOTHING));
+      } else {
+        wait_time = std::min(kIdleTimeDelta, latest_possible_paint_time_ - now);
       }
 
-      UpdateStatsAndWait_Locked(kIdleTimeDelta);
+      UpdateStatsAndWait_Locked(wait_time);
       continue;
     }
 
     base::TimeTicks target_paint_time =
         wall_clock_time_cb_.Run(ready_frames_.front()->timestamp());
 
     // If media time has stopped, don't attempt to paint any more frames.
     if (target_paint_time.is_null()) {
       UpdateStatsAndWait_Locked(kIdleTimeDelta);
       continue;
     }
 
-    base::TimeTicks latest_possible_paint_time;
-
     // Deadline is defined as the duration between this frame and the next
     // frame, using the delta between this frame and the previous frame as the
     // assumption for frame duration.
     //
     // TODO(scherkus): This can be vastly improved. Use a histogram to measure
     // the accuracy of our frame timing code. http://crbug.com/149829
     if (last_media_time_.is_null()) {
-      latest_possible_paint_time = now;
+      latest_possible_paint_time_ = now;
     } else {
       base::TimeDelta duration = target_paint_time - last_media_time_;
-      latest_possible_paint_time = target_paint_time + duration;
+      latest_possible_paint_time_ = target_paint_time + duration;
     }
 
     // Remain idle until we've reached our target paint window.
     if (now < target_paint_time) {
       UpdateStatsAndWait_Locked(
           std::min(target_paint_time - now, kIdleTimeDelta));
       continue;
     }
 
-    if (ready_frames_.size() > 1 && now > latest_possible_paint_time &&
+    if (ready_frames_.size() > 1 && now > latest_possible_paint_time_ &&
         drop_frames_) {
       DropNextReadyFrame_Locked();
       continue;
     }
 
     // Congratulations! You've made it past the video frame timing gauntlet.
     //
     // At this point enough time has passed that the next frame that ready for
     // rendering.
     PaintNextReadyFrame_Locked();
   }
 }
 
 void VideoRendererImpl::SetTickClockForTesting(
     scoped_ptr<base::TickClock> tick_clock) {
   tick_clock_.swap(tick_clock);
 }
 
 void VideoRendererImpl::PaintNextReadyFrame_Locked() {
   lock_.AssertAcquired();
 
   scoped_refptr<VideoFrame> next_frame = ready_frames_.front();
   ready_frames_.pop_front();
   frames_decoded_++;
 
-  last_media_time_ = last_painted_time_ =
-      wall_clock_time_cb_.Run(next_frame->timestamp());
+  last_media_time_ = wall_clock_time_cb_.Run(next_frame->timestamp());
 
   paint_cb_.Run(next_frame);
 
   task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&VideoRendererImpl::AttemptRead, weak_factory_.GetWeakPtr()));
 }
 
 void VideoRendererImpl::DropNextReadyFrame_Locked() {
   TRACE_EVENT0("media", "VideoRendererImpl:frameDropped");
@@ skipping 136 matching lines @@
 void VideoRendererImpl::OnVideoFrameStreamResetDone() {
   base::AutoLock auto_lock(lock_);
   DCHECK_EQ(kFlushing, state_);
   DCHECK(!pending_read_);
   DCHECK(ready_frames_.empty());
   DCHECK(!received_end_of_stream_);
   DCHECK(!rendered_end_of_stream_);
   DCHECK_EQ(buffering_state_, BUFFERING_HAVE_NOTHING);
 
   state_ = kFlushed;
-  last_media_time_ = last_painted_time_ = base::TimeTicks();
+  latest_possible_paint_time_ = last_media_time_ = base::TimeTicks();
   base::ResetAndReturn(&flush_cb_).Run();
 }
 
 void VideoRendererImpl::UpdateStatsAndWait_Locked(
     base::TimeDelta wait_duration) {
   lock_.AssertAcquired();
   DCHECK_GE(frames_decoded_, 0);
   DCHECK_LE(frames_dropped_, frames_decoded_);
 
   if (frames_decoded_) {
     PipelineStatistics statistics;
     statistics.video_frames_decoded = frames_decoded_;
     statistics.video_frames_dropped = frames_dropped_;
     task_runner_->PostTask(FROM_HERE, base::Bind(statistics_cb_, statistics));
 
     frames_decoded_ = 0;
     frames_dropped_ = 0;
   }
 
   frame_available_.TimedWait(wait_duration);
 }
 
 }  // namespace media