commit 1d6a5087d24da169b1c9e8f5a250c857369545fa
author Jakob Ivarsson <jakobi@webrtc.org> Mon Jan 09 14:36:51 2023
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jan 09 19:02:05 2023
tree 5b0d48c48b53850cff5a384787f9df83470dcb26
parent 11dfb42fe9daf8ca01366ae0e8c7985d50430e52

Stop CNG after a timeout.

After having generated one second of comfort noise and not received any packets, switch to expand mode which will fade out to silence and enter the efficient muted mode.

The behavior is enabled by default but can be disabled through a field trial.

Bug: webrtc:12790
Change-Id: I1e2c1acced3e4a2c1c1595824f1303a0c339aeb5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/290578
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Jakob Ivarsson‎ <jakobi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39043}

modules/audio_coding/neteq/decision_logic.cc

diff --git a/modules/audio_coding/neteq/decision_logic.cc b/modules/audio_coding/neteq/decision_logic.cc
index 558774d..91b0252 100644
--- a/modules/audio_coding/neteq/decision_logic.cc
+++ b/modules/audio_coding/neteq/decision_logic.cc
@@ -71,6 +71,7 @@
       "enable_stable_playout_delay", &enable_stable_playout_delay,  //
       "reinit_after_expands", &reinit_after_expands,                //
       "packet_history_size_ms", &packet_history_size_ms,            //
+      "cng_timeout_ms", &cng_timeout_ms,                            //
       "deceleration_target_level_offset_ms",
       &deceleration_target_level_offset_ms)
       ->Parse(webrtc::field_trial::FindFullName(
@@ -80,6 +81,7 @@
                    << enable_stable_playout_delay
                    << " reinit_after_expands=" << reinit_after_expands
                    << " packet_history_size_ms=" << packet_history_size_ms
+                   << " cng_timeout_ms=" << cng_timeout_ms.value_or(-1)
                    << " deceleration_target_level_offset_ms="
                    << deceleration_target_level_offset_ms;
 }
@@ -320,7 +322,12 @@
     // Keep on playing comfort noise.
     return NetEq::Operation::kRfc3389CngNoPacket;
   } else if (cng_state_ == kCngInternalOn) {
-    // Keep on playing codec internal comfort noise.
+    // Stop CNG after a timeout.
+    if (config_.cng_timeout_ms &&
+        status.generated_noise_samples >
+            static_cast<size_t>(*config_.cng_timeout_ms * sample_rate_khz_)) {
+      return NetEq::Operation::kExpand;
+    }
     return NetEq::Operation::kCodecInternalCng;
   } else if (status.play_dtmf) {
     return NetEq::Operation::kDtmf;

modules/audio_coding/neteq/decision_logic.h

diff --git a/modules/audio_coding/neteq/decision_logic.h b/modules/audio_coding/neteq/decision_logic.h
index 2e55322..69b13a9 100644
--- a/modules/audio_coding/neteq/decision_logic.h
+++ b/modules/audio_coding/neteq/decision_logic.h
@@ -175,6 +175,7 @@
     int reinit_after_expands = 100;
     int deceleration_target_level_offset_ms = 85;
     int packet_history_size_ms = 2000;
+    absl::optional<int> cng_timeout_ms = 1000;
   };
   Config config_;
   std::unique_ptr<DelayManager> delay_manager_;

modules/audio_coding/neteq/decision_logic_unittest.cc

diff --git a/modules/audio_coding/neteq/decision_logic_unittest.cc b/modules/audio_coding/neteq/decision_logic_unittest.cc
index d70e307..d0473d0 100644
--- a/modules/audio_coding/neteq/decision_logic_unittest.cc
+++ b/modules/audio_coding/neteq/decision_logic_unittest.cc
@@ -201,4 +201,16 @@
   }
 }
 
+TEST_F(DecisionLogicTest, CngTimeout) {
+  auto status = CreateNetEqStatus(NetEq::Mode::kCodecInternalCng, 0);
+  status.next_packet = absl::nullopt;
+  status.generated_noise_samples = kSamplesPerMs * 500;
+  bool reset_decoder = false;
+  EXPECT_EQ(decision_logic_->GetDecision(status, &reset_decoder),
+            NetEq::Operation::kCodecInternalCng);
+  status.generated_noise_samples = kSamplesPerMs * 1010;
+  EXPECT_EQ(decision_logic_->GetDecision(status, &reset_decoder),
+            NetEq::Operation::kExpand);
+}
+
 }  // namespace webrtc