[Cast] Track audio queued in encoder; account for it in ShouldDropNextFrame().

media/cast/sender/frame_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.
 //
 // This is the base class for an object that send frames to a receiver.
 // TODO(hclam): Refactor such that there is no separate AudioSender vs.
 // VideoSender, and the functionality of both is rolled into this class.
 
 #ifndef MEDIA_CAST_SENDER_FRAME_SENDER_H_
 #define MEDIA_CAST_SENDER_FRAME_SENDER_H_
@@ skipping 70 matching lines @@
   // Record or retrieve a recent history of each frame's timestamps.
   // Warning: If a frame ID too far in the past is requested, the getters will
   // silently succeed but return incorrect values.  Be sure to respect
   // media::cast::kMaxUnackedFrames.
   void RecordLatestFrameTimestamps(uint32 frame_id,
                                    base::TimeTicks reference_time,
                                    RtpTimestamp rtp_timestamp);
   base::TimeTicks GetRecordedReferenceTime(uint32 frame_id) const;
   RtpTimestamp GetRecordedRtpTimestamp(uint32 frame_id) 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;
+
   const base::TimeDelta rtcp_interval_;
 
   // The total amount of time between a frame's capture/recording on the sender
   // and its playback on the receiver (i.e., shown to a user).  This is fixed as
   // a value large enough to give the system sufficient time to encode,
   // transmit/retransmit, receive, decode, and render; given its run-time
   // environment (sender/receiver hardware performance, network conditions,
   // etc.).
   base::TimeDelta target_playout_delay_;
 
   // If true, we transmit the target playout delay to the receiver.
   bool send_target_playout_delay_;
 
   // Max encoded frames generated per second.
   double max_frame_rate_;
 
   // Maximum number of outstanding frames before the encoding and sending of
   // new frames shall halt.
   int max_unacked_frames_;
 
+  // The number of frames queued for encoding, but not yet sent.
+  int frames_in_encoder_;
+
   // Counts how many RTCP reports are being "aggressively" sent (i.e., one per
   // frame) at the start of the session.  Once a threshold is reached, RTCP
   // reports are instead sent at the configured interval + random drift.
   int num_aggressive_rtcp_reports_sent_;
 
   // This is "null" until the first frame is sent.  Thereafter, this tracks the
   // last time any frame was sent or re-sent.
   base::TimeTicks last_send_time_;
 
   // The ID of the last frame sent.  Logic throughout FrameSender assumes this
@@ skipping 29 matching lines @@
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FrameSender> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameSender);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_SENDER_FRAME_SENDER_H_