cast: Support for low-latency interactive mode

media/cast/sender/frame_sender.cc

 // 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.
 
 #include "media/cast/sender/frame_sender.h"
 
+#include <algorithm>
+#include <vector>
+
 #include "base/trace_event/trace_event.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/constants.h"
 #include "media/cast/sender/sender_encoded_frame.h"
 
 namespace media {
 namespace cast {
 namespace {
 
 const int kMinSchedulingDelayMs = 1;
@@ skipping 13 matching lines @@
                          CastTransportSender* const transport_sender,
                          int rtp_timebase,
                          uint32 ssrc,
                          double max_frame_rate,
                          base::TimeDelta min_playout_delay,
                          base::TimeDelta max_playout_delay,
                          CongestionControl* congestion_control)
     : cast_environment_(cast_environment),
       transport_sender_(transport_sender),
       ssrc_(ssrc),
-      min_playout_delay_(min_playout_delay == base::TimeDelta() ?
-                         max_playout_delay : min_playout_delay),
+      min_playout_delay_(min_playout_delay),

[miu, 2015/12/01 21:15:27]

Sanity-check: Can min_playout_delay ever be zero?  Should we at least do
something like this here: std::max(50 milliseconds, min_playout_delay)

[Irfan, 2015/12/02 22:32:44]

I have gone to previous logic since if there is no min provided, I want to
disable the dynamic playout delay adjustment.

If there is just max provided (400) like now, we will basically end up with
fixed playout delay at all time.

       max_playout_delay_(max_playout_delay),
       send_target_playout_delay_(false),
       max_frame_rate_(max_frame_rate),
       num_aggressive_rtcp_reports_sent_(0),
       last_sent_frame_id_(0),
       latest_acked_frame_id_(0),
       duplicate_ack_counter_(0),
       congestion_control_(congestion_control),
       rtp_timebase_(rtp_timebase),
       is_audio_(is_audio),
       weak_factory_(this) {
   DCHECK(transport_sender_);
   DCHECK_GT(rtp_timebase_, 0);
   DCHECK(congestion_control_);
-  SetTargetPlayoutDelay(min_playout_delay_);
+  SetTargetPlayoutDelay(
+      base::TimeDelta::FromMilliseconds(kNonInteractiveModeStartPlayoutTimeMs));
   send_target_playout_delay_ = false;
   memset(frame_rtp_timestamps_, 0, sizeof(frame_rtp_timestamps_));
 }
 
 FrameSender::~FrameSender() {
 }
 
 void FrameSender::ScheduleNextRtcpReport() {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
 
@@ skipping 335 matching lines @@
     VLOG(1) << SENDER_SSRC << "Dropping: In-flight duration would be too high.";
     return true;
   }
 
   // Next frame is accepted.
   return false;
 }
 
 }  // namespace cast
 }  // namespace media