commit 00eb12a20cd29cf249e9ac7cfe0a8037a1e5f903
author Henrik Lundin <henrik.lundin@webrtc.org> Wed Sep 05 18:14:52 2018 +0200
committer Commit Bot <commit-bot@chromium.org> Fri Sep 14 07:05:20 2018 +0000
tree 40abdce0efb2420289f0073d39257fc721777649
parent e899629be4d8c86d3b26440b51d29db39c19b490

Let NetEq use the PLC output from a decoder

This change enables NetEq to use the packet concealment audio (aka
PLC) produced by a decoder. The change also includes a new API to the
AudioDecoder interface, which lets the decoder implementation generate
and deliver concealment audio.

Bug: webrtc:9180
Change-Id: Icaacebccf645d4694b0d2d6310f6f2c7132881c4
Reviewed-on: https://webrtc-review.googlesource.com/96340
Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24738}

modules/audio_coding/neteq/neteq_impl.cc

diff --git a/modules/audio_coding/neteq/neteq_impl.cc b/modules/audio_coding/neteq/neteq_impl.cc
index 98c2372..857a4d7 100644
--- a/modules/audio_coding/neteq/neteq_impl.cc
+++ b/modules/audio_coding/neteq/neteq_impl.cc
@@ -885,7 +885,12 @@
       break;
     }
     case kExpand: {
-      return_value = DoExpand(play_dtmf);
+      RTC_DCHECK_EQ(return_value, 0);
+      if (!current_rtp_payload_type_ || !DoCodecPlc()) {
+        return_value = DoExpand(play_dtmf);
+      }
+      RTC_DCHECK_GE(sync_buffer_->FutureLength() - expand_->overlap_length(),
+                    output_size_samples_);
       break;
     }
     case kAccelerate:
@@ -997,7 +1002,7 @@
     sync_buffer_->set_dtmf_index(sync_buffer_->Size());
   }
 
-  if (last_mode_ != kModeExpand) {
+  if (last_mode_ != kModeExpand && last_mode_ != kModeCodecPlc) {
     // If last operation was not expand, calculate the |playout_timestamp_| from
     // the |sync_buffer_|. However, do not update the |playout_timestamp_| if it
     // would be moved "backwards".
@@ -1022,7 +1027,7 @@
                 static_cast<uint32_t>(audio_frame->samples_per_channel_);
 
   if (!(last_mode_ == kModeRfc3389Cng || last_mode_ == kModeCodecInternalCng ||
-        last_mode_ == kModeExpand)) {
+        last_mode_ == kModeExpand || last_mode_ == kModeCodecPlc)) {
     generated_noise_stopwatch_.reset();
   }
 
@@ -1541,6 +1546,48 @@
   }
 }
 
+bool NetEqImpl::DoCodecPlc() {
+  AudioDecoder* decoder = decoder_database_->GetActiveDecoder();
+  if (!decoder) {
+    return false;
+  }
+  const size_t channels = algorithm_buffer_->Channels();
+  const size_t requested_samples_per_channel =
+      output_size_samples_ -
+      (sync_buffer_->FutureLength() - expand_->overlap_length());
+  concealment_audio_.Clear();
+  decoder->GeneratePlc(requested_samples_per_channel, &concealment_audio_);
+  if (concealment_audio_.empty()) {
+    // Nothing produced. Resort to regular expand.
+    return false;
+  }
+  RTC_CHECK_GE(concealment_audio_.size(),
+               requested_samples_per_channel * channels);
+  sync_buffer_->PushBackInterleaved(concealment_audio_);
+  RTC_DCHECK_NE(algorithm_buffer_->Channels(), 0);
+  const size_t concealed_samples_per_channel =
+      concealment_audio_.size() / channels;
+
+  // Update in-call and post-call statistics.
+  const bool is_new_concealment_event = (last_mode_ != kModeCodecPlc);
+  if (std::all_of(concealment_audio_.cbegin(), concealment_audio_.cend(),
+                  [](int16_t i) { return i == 0; })) {
+    // Expand operation generates only noise.
+    stats_.ExpandedNoiseSamples(concealed_samples_per_channel,
+                                is_new_concealment_event);
+  } else {
+    // Expand operation generates more than only noise.
+    stats_.ExpandedVoiceSamples(concealed_samples_per_channel,
+                                is_new_concealment_event);
+  }
+  last_mode_ = kModeCodecPlc;
+  if (!generated_noise_stopwatch_) {
+    // Start a new stopwatch since we may be covering for a lost CNG packet.
+    generated_noise_stopwatch_ = tick_timer_->GetNewStopwatch();
+  }
+  return true;
+}
+
 int NetEqImpl::DoExpand(bool play_dtmf) {
   while ((sync_buffer_->FutureLength() - expand_->overlap_length()) <
          output_size_samples_) {