From 6a61762659e8578b3072d9189311a4d2cfe5fb93 Mon Sep 17 00:00:00 2001
From: David Kelly <david@highfidelity.io>
Date: Wed, 26 Oct 2016 17:41:34 -0700
Subject: [PATCH] First try

AudioMixer has same issue transitioning from silence to encoded
audio and back, it seems.  This makes that go away, but I don't
like it.  Better to support a flush function in the encoder but
for now lets do this and be sure it is the entire issue.
---
 assignment-client/src/audio/AudioMixer.cpp           |  6 ++++++
 assignment-client/src/audio/AudioMixerClientData.cpp | 10 ++++++++++
 assignment-client/src/audio/AudioMixerClientData.h   |  4 ++++
 3 files changed, 20 insertions(+)

diff --git a/assignment-client/src/audio/AudioMixer.cpp b/assignment-client/src/audio/AudioMixer.cpp
index 0252c037bf..e580c62905 100644
--- a/assignment-client/src/audio/AudioMixer.cpp
+++ b/assignment-client/src/audio/AudioMixer.cpp
@@ -819,6 +819,9 @@ void AudioMixer::broadcastMixes() {
                     std::unique_ptr<NLPacket> mixPacket;
 
                     if (mixHasAudio) {
+                        // may need to flush, this checks
+                        nodeData->flushEncoder();
+                        
                         int mixPacketBytes = sizeof(quint16) + AudioConstants::MAX_CODEC_NAME_LENGTH_ON_WIRE 
                                                              + AudioConstants::NETWORK_FRAME_BYTES_STEREO;
                         mixPacket = NLPacket::create(PacketType::MixedAudio, mixPacketBytes);
@@ -852,6 +855,9 @@ void AudioMixer::broadcastMixes() {
                         // pack number of silent audio samples
                         quint16 numSilentSamples = AudioConstants::NETWORK_FRAME_SAMPLES_STEREO;
                         mixPacket->writePrimitive(numSilentSamples);
+
+                        // we will need to flush encoder since we are sending silent packets outside it
+                        nodeData->shouldFlushEncoder();
                     }
 
                     // Send audio environment
diff --git a/assignment-client/src/audio/AudioMixerClientData.cpp b/assignment-client/src/audio/AudioMixerClientData.cpp
index 1eb36cd8a7..a0b96ff39b 100644
--- a/assignment-client/src/audio/AudioMixerClientData.cpp
+++ b/assignment-client/src/audio/AudioMixerClientData.cpp
@@ -366,6 +366,16 @@ void AudioMixerClientData::sendSelectAudioFormat(SharedNodePointer node, const Q
     nodeList->sendPacket(std::move(replyPacket), *node);
 }
 
+void AudioMixerClientData::flushEncoder() {
+    static QByteArray zeros(AudioConstants::NETWORK_FRAME_BYTES_STEREO, 0);
+    static QByteArray encodedZeros;
+    if (_shouldFlushEncoder) {
+        _shouldFlushEncoder = false;
+        if (_encoder) {
+            _encoder->encode(zeros, encodedZeros);
+        }
+    }
+}
 
 void AudioMixerClientData::setupCodec(CodecPluginPointer codec, const QString& codecName) {
     cleanupCodec(); // cleanup any previously allocated coders first
diff --git a/assignment-client/src/audio/AudioMixerClientData.h b/assignment-client/src/audio/AudioMixerClientData.h
index 2f8ff4d049..51f06b41c4 100644
--- a/assignment-client/src/audio/AudioMixerClientData.h
+++ b/assignment-client/src/audio/AudioMixerClientData.h
@@ -77,6 +77,8 @@ public:
             encodedBuffer = decodedBuffer;
         }
     }
+    void flushEncoder();
+    void shouldFlushEncoder() { _shouldFlushEncoder = true; }
 
     QString getCodecName() { return _selectedCodecName; }
 
@@ -105,6 +107,8 @@ private:
     QString _selectedCodecName;
     Encoder* _encoder{ nullptr }; // for outbound mixed stream
     Decoder* _decoder{ nullptr }; // for mic stream
+
+    bool _shouldFlushEncoder { false };
 };
 
 #endif // hifi_AudioMixerClientData_h