cast: Support for low-latency interactive mode

media/cast/sender/frame_sender.cc

Index: media/cast/sender/frame_sender.cc
diff --git a/media/cast/sender/frame_sender.cc b/media/cast/sender/frame_sender.cc
index 44f505e8c26c03e3d9d6864fd5fa2fcc11296c45..98386fa93aed658d917b109376500a2f3304983a 100644
--- a/media/cast/sender/frame_sender.cc
+++ b/media/cast/sender/frame_sender.cc
@@ -4,6 +4,9 @@
 
 #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"
@@ -33,13 +36,18 @@ FrameSender::FrameSender(scoped_refptr<CastEnvironment> cast_environment,
                          double max_frame_rate,
                          base::TimeDelta min_playout_delay,
                          base::TimeDelta max_playout_delay,
+                         base::TimeDelta animated_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 == base::TimeDelta()
+                             ? max_playout_delay
+                             : min_playout_delay),
       max_playout_delay_(max_playout_delay),
+      animated_playout_delay_(animated_playout_delay == base::TimeDelta()
+                                  ? max_playout_delay
+                                  : animated_playout_delay),
       send_target_playout_delay_(false),
       max_frame_rate_(max_frame_rate),
       num_aggressive_rtcp_reports_sent_(0),
@@ -53,7 +61,12 @@ FrameSender::FrameSender(scoped_refptr<CastEnvironment> cast_environment,
   DCHECK(transport_sender_);
   DCHECK_GT(rtp_timebase_, 0);
   DCHECK(congestion_control_);
-  SetTargetPlayoutDelay(min_playout_delay_);
+  // We assume animated content to begin with since that is the common use
+  // case today.
+  VLOG(1) << "min latency " << min_playout_delay_.InMilliseconds()

[miu, 2015/12/03 21:26:23]

nit: VLOG(1) << SENDER_SSRC << ...and the rest...

[Irfan, 2015/12/04 22:45:37]

Done.

+          << "max latency " << max_playout_delay.InMilliseconds()
+          << "animated latency " << animated_playout_delay.InMilliseconds();
+  SetTargetPlayoutDelay(animated_playout_delay_);
   send_target_playout_delay_ = false;
   memset(frame_rtp_timestamps_, 0, sizeof(frame_rtp_timestamps_));
 }