Cast: First stab at implementing adaptive latency

After a bunch of testing, it seems like there is a direct linear
relationship between RTT and the optimal playout delay. Packet loss
is also a factor, but since we expect packet loss to be low in
normal networks, perhaps we can make the formula as easy as RTT * 4.

This is disabled by default, the extension needs to set min_latency_ms
in order to activate it.

BUG=405339

Review URL: https://codereview.chromium.org/562653004

Cr-Commit-Position: refs/heads/master@{#294655}

5 files changed, 20 insertions, 14 deletions

diff --git a/media/cast/test/cast_benchmarks.cc b/media/cast/test/cast_benchmarks.cc
index 6a6f8b2..880f4ad 100644
--- a/media/cast/test/cast_benchmarks.cc
+++ b/media/cast/test/cast_benchmarks.cc
@@ -225,7 +225,7 @@ class RunOneBenchmark {
                  int max_number_of_video_buffers_used) {
     audio_sender_config_.ssrc = 1;
     audio_sender_config_.incoming_feedback_ssrc = 2;
-    audio_sender_config_.target_playout_delay =
+    audio_sender_config_.max_playout_delay =
         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
     audio_sender_config_.rtp_payload_type = 96;
     audio_sender_config_.use_external_encoder = false;
@@ -247,7 +247,7 @@ class RunOneBenchmark {
 
     video_sender_config_.ssrc = 3;
     video_sender_config_.incoming_feedback_ssrc = 4;
-    video_sender_config_.target_playout_delay =
+    video_sender_config_.max_playout_delay =
         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
     video_sender_config_.rtp_payload_type = 97;
     video_sender_config_.use_external_encoder = false;
diff --git a/media/cast/test/end2end_unittest.cc b/media/cast/test/end2end_unittest.cc
index eea3902..a0a7d1e 100644
--- a/media/cast/test/end2end_unittest.cc
+++ b/media/cast/test/end2end_unittest.cc
@@ -474,7 +474,7 @@ class End2EndTest : public ::testing::Test {
                  int max_number_of_video_buffers_used) {
     audio_sender_config_.ssrc = 1;
     audio_sender_config_.incoming_feedback_ssrc = 2;
-    audio_sender_config_.target_playout_delay =
+    audio_sender_config_.max_playout_delay =
         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
     audio_sender_config_.rtp_payload_type = 96;
     audio_sender_config_.use_external_encoder = false;
@@ -499,7 +499,7 @@ class End2EndTest : public ::testing::Test {
 
     video_sender_config_.ssrc = 3;
     video_sender_config_.incoming_feedback_ssrc = 4;
-    video_sender_config_.target_playout_delay =
+    video_sender_config_.max_playout_delay =
         base::TimeDelta::FromMilliseconds(kTargetPlayoutDelayMs);
     video_sender_config_.rtp_payload_type = 97;
     video_sender_config_.use_external_encoder = false;
@@ -995,9 +995,9 @@ TEST_F(End2EndTest, DISABLED_StartSenderBeforeReceiver) {
 TEST_F(End2EndTest, DropEveryOtherFrame3Buffers) {
   Configure(CODEC_VIDEO_VP8, CODEC_AUDIO_OPUS, kDefaultAudioSamplingRate, 3);
   int target_delay = 300;
-  video_sender_config_.target_playout_delay =
+  video_sender_config_.max_playout_delay =
       base::TimeDelta::FromMilliseconds(target_delay);
-  audio_sender_config_.target_playout_delay =
+  audio_sender_config_.max_playout_delay =
       base::TimeDelta::FromMilliseconds(target_delay);
   video_receiver_config_.rtp_max_delay_ms = target_delay;
   Create();
@@ -1436,6 +1436,12 @@ TEST_F(End2EndTest, OldPacketNetwork) {
 
 TEST_F(End2EndTest, TestSetPlayoutDelay) {
   Configure(CODEC_VIDEO_FAKE, CODEC_AUDIO_PCM16, 32000, 1);
+  video_sender_config_.min_playout_delay =
+      video_sender_config_.max_playout_delay;
+  audio_sender_config_.min_playout_delay =
+      audio_sender_config_.max_playout_delay;
+  video_sender_config_.max_playout_delay = base::TimeDelta::FromSeconds(1);
+  audio_sender_config_.max_playout_delay = base::TimeDelta::FromSeconds(1);
   Create();
   StartBasicPlayer();
   const int kNewDelay = 600;
diff --git a/media/cast/test/sender.cc b/media/cast/test/sender.cc
index c18645a..38aef30 100644
--- a/media/cast/test/sender.cc
+++ b/media/cast/test/sender.cc
@@ -75,7 +75,7 @@ media::cast::AudioSenderConfig GetAudioSenderConfig() {
   audio_config.rtp_payload_type = 127;
   // TODO(miu): The default in cast_defines.h is 100.  Should this be 100, and
   // should receiver.cc's config also be 100?
-  audio_config.target_playout_delay = base::TimeDelta::FromMilliseconds(300);
+  audio_config.max_playout_delay = base::TimeDelta::FromMilliseconds(300);
   return audio_config;
 }
 
@@ -109,7 +109,7 @@ media::cast::VideoSenderConfig GetVideoSenderConfig() {
   video_config.rtp_payload_type = 96;
   // TODO(miu): The default in cast_defines.h is 100.  Should this be 100, and
   // should receiver.cc's config also be 100?
-  video_config.target_playout_delay = base::TimeDelta::FromMilliseconds(300);
+  video_config.max_playout_delay = base::TimeDelta::FromMilliseconds(300);
   return video_config;
 }
 
diff --git a/media/cast/test/simulator.cc b/media/cast/test/simulator.cc
index fbb36f8..df1c739 100644
--- a/media/cast/test/simulator.cc
+++ b/media/cast/test/simulator.cc
@@ -219,28 +219,28 @@ void RunSimulation(const base::FilePath& source_path,
 
   // Audio sender config.
   AudioSenderConfig audio_sender_config = GetDefaultAudioSenderConfig();
-  audio_sender_config.target_playout_delay =
+  audio_sender_config.max_playout_delay =
       base::TimeDelta::FromMilliseconds(kTargetDelay);
 
   // Audio receiver config.
   FrameReceiverConfig audio_receiver_config =
       GetDefaultAudioReceiverConfig();
   audio_receiver_config.rtp_max_delay_ms =
-      audio_sender_config.target_playout_delay.InMilliseconds();
+      audio_sender_config.max_playout_delay.InMilliseconds();
 
   // Video sender config.
   VideoSenderConfig video_sender_config = GetDefaultVideoSenderConfig();
   video_sender_config.max_bitrate = 2500000;
   video_sender_config.min_bitrate = 2000000;
   video_sender_config.start_bitrate = 2000000;
-  video_sender_config.target_playout_delay =
+  video_sender_config.max_playout_delay =
       base::TimeDelta::FromMilliseconds(kTargetDelay);
 
   // Video receiver config.
   FrameReceiverConfig video_receiver_config =
       GetDefaultVideoReceiverConfig();
   video_receiver_config.rtp_max_delay_ms =
-      video_sender_config.target_playout_delay.InMilliseconds();
+      video_sender_config.max_playout_delay.InMilliseconds();
 
   // Loopback transport.
   LoopBackTransport receiver_to_sender(receiver_env);
diff --git a/media/cast/test/utility/default_config.cc b/media/cast/test/utility/default_config.cc
index ce81eba..2496e71 100644
--- a/media/cast/test/utility/default_config.cc
+++ b/media/cast/test/utility/default_config.cc
@@ -62,7 +62,7 @@ AudioSenderConfig GetDefaultAudioSenderConfig() {
   config.channels = recv_config.channels;
   config.bitrate = kDefaultAudioEncoderBitrate;
   config.codec = recv_config.codec;
-  config.target_playout_delay =
+  config.max_playout_delay =
       base::TimeDelta::FromMilliseconds(kDefaultRtpMaxDelayMs);
   return config;
 }
@@ -83,7 +83,7 @@ VideoSenderConfig GetDefaultVideoSenderConfig() {
   config.max_number_of_video_buffers_used = 1;
   config.codec = recv_config.codec;
   config.number_of_encode_threads = 2;
-  config.target_playout_delay =
+  config.max_playout_delay =
       base::TimeDelta::FromMilliseconds(kDefaultRtpMaxDelayMs);
   return config;
 }