[Cast] In Audio/VideoSender, drop frames when too-long a duration is in-flight.

media/cast/sender/video_sender.h

 // Copyright 2014 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.
 
 #ifndef MEDIA_CAST_SENDER_VIDEO_SENDER_H_
 #define MEDIA_CAST_SENDER_VIDEO_SENDER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 43 matching lines @@
   // Note: It is invalid to call this method if InitializationResult() returns
   // anything but STATUS_VIDEO_INITIALIZED.
   void InsertRawVideoFrame(const scoped_refptr<media::VideoFrame>& video_frame,
                            const base::TimeTicks& capture_time);
 
  protected:
   // Protected for testability.
   void OnReceivedCastFeedback(const RtcpCastMessage& cast_feedback);
 
  private:
-  // Returns true if there are too many frames in flight, as defined by the
-  // configured target playout delay plus simple logic.  When this is true,
-  // InsertRawVideoFrame() will silenty drop frames instead of sending them to
-  // the video encoder.
-  bool AreTooManyFramesInFlight() const;
+  // Returns true if there are too many frames in flight, or if the media
+  // duration of the frames in flight would be too high by sending the next
+  // frame.  The latter metric is determined from the given |capture_time|
+  // for the next frame to be encoded and sent.
+  bool ShouldDropNextFrame(base::TimeTicks capture_time) const;
 
   // Called by the |video_encoder_| with the next EncodeFrame to send.
   void SendEncodedVideoFrame(int requested_bitrate_before_encode,
                              scoped_ptr<EncodedFrame> encoded_frame);
   // If this value is non zero then a fixed value is used for bitrate.
   // If external video encoder is used then bitrate will be fixed to
   // (min_bitrate + max_bitrate) / 2.
   const size_t fixed_bitrate_;
 
   // Encodes media::VideoFrame images into EncodedFrames.  Per configuration,
@@ skipping 12 matching lines @@
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoSender> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoSender);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_SENDER_VIDEO_SENDER_H_