From aa3602f0fb5fa0def615377e25dd52e2f33e5a3f Mon Sep 17 00:00:00 2001
From: wangyix <wangyix@gmail.com>
Date: Thu, 19 Jun 2014 14:34:55 -0700
Subject: [PATCH] added InterframeTimeGapHistory and frameReceived() calls

---
 .../src/audio/AvatarAudioRingBuffer.cpp       |  2 +
 libraries/audio/src/AudioRingBuffer.cpp       | 57 +++++++++++++++++++
 libraries/audio/src/AudioRingBuffer.h         | 28 +++++++++
 .../audio/src/InjectedAudioRingBuffer.cpp     |  2 +
 4 files changed, 89 insertions(+)

diff --git a/assignment-client/src/audio/AvatarAudioRingBuffer.cpp b/assignment-client/src/audio/AvatarAudioRingBuffer.cpp
index 5613a64cc4..47a0ecbea8 100644
--- a/assignment-client/src/audio/AvatarAudioRingBuffer.cpp
+++ b/assignment-client/src/audio/AvatarAudioRingBuffer.cpp
@@ -19,6 +19,8 @@ AvatarAudioRingBuffer::AvatarAudioRingBuffer(bool isStereo) :
 }
 
 int AvatarAudioRingBuffer::parseData(const QByteArray& packet) {
+    _timeGapHistory.frameReceived();
+
     _shouldLoopbackForNode = (packetTypeForPacket(packet) == PacketTypeMicrophoneAudioWithEcho);
     return PositionalAudioRingBuffer::parseData(packet);
 }
diff --git a/libraries/audio/src/AudioRingBuffer.cpp b/libraries/audio/src/AudioRingBuffer.cpp
index 2101fcb9cd..ea15e27ef5 100644
--- a/libraries/audio/src/AudioRingBuffer.cpp
+++ b/libraries/audio/src/AudioRingBuffer.cpp
@@ -12,6 +12,7 @@
 #include <cstring>
 #include <functional>
 #include <math.h>
+#include "SharedUtil.h"
 
 #include <QtCore/QDebug>
 
@@ -19,6 +20,62 @@
 
 #include "AudioRingBuffer.h"
 
+InterframeTimeGapHistory::InterframeTimeGapHistory()
+    : _lastFrameReceivedTime(0),
+    _numSamplesInCurrentInterval(0),
+    _currentIntervalMaxGap(0),
+    _newestIntervalMaxGapAt(0),
+    _windowMaxGap(0),
+    _newWindowMaxGapAvailable(false)
+{
+    memset(_intervalMaxGaps, 0, TIME_GAP_NUM_INTERVALS_IN_WINDOW*sizeof(quint64));
+}
+
+void InterframeTimeGapHistory::frameReceived() {
+    quint64 now = usecTimestampNow();
+
+    // make sure this isn't the first time frameReceived() is called, meaning there's actually a gap to calculate.
+    if (_lastFrameReceivedTime != 0) {
+        quint64 gap = now - _lastFrameReceivedTime;
+
+        // update the current interval max
+        if (gap > _currentIntervalMaxGap) {
+            _currentIntervalMaxGap = gap;
+        }
+        _numSamplesInCurrentInterval++;
+
+        // if the current interval of samples is now full, record it in our interval maxes
+        if (_numSamplesInCurrentInterval == TIME_GAP_NUM_SAMPLES_IN_INTERVAL) {
+
+            // find location to insert this interval's max (increment index cyclically)
+            _newestIntervalMaxGapAt = _newestIntervalMaxGapAt == TIME_GAP_NUM_INTERVALS_IN_WINDOW - 1 ? 0 : _newestIntervalMaxGapAt + 1;
+
+            // record the current interval's max gap as the newest
+            _intervalMaxGaps[_newestIntervalMaxGapAt] = _currentIntervalMaxGap;
+
+            // update the window max gap, which is the max out of all the past intervals' max gaps
+            _windowMaxGap = 0;
+            for (int i = 0; i < TIME_GAP_NUM_INTERVALS_IN_WINDOW; i++) {
+                if (_intervalMaxGaps[i] > _windowMaxGap) {
+                    _windowMaxGap = _intervalMaxGaps[i];
+                }
+            }
+            _newWindowMaxGapAvailable = true;
+
+            // reset the current interval
+            _numSamplesInCurrentInterval = 0;
+            _currentIntervalMaxGap = 0;
+        }
+    }
+    _lastFrameReceivedTime = now;
+}
+
+quint64 InterframeTimeGapHistory::getPastWindowMaxGap() {
+    _newWindowMaxGapAvailable = false;
+    return _windowMaxGap;
+}
+
+
 AudioRingBuffer::AudioRingBuffer(int numFrameSamples, bool randomAccessMode) :
     NodeData(),
     _sampleCapacity(numFrameSamples * RING_BUFFER_LENGTH_FRAMES),
diff --git a/libraries/audio/src/AudioRingBuffer.h b/libraries/audio/src/AudioRingBuffer.h
index 04cc67c8ac..105e3761ae 100644
--- a/libraries/audio/src/AudioRingBuffer.h
+++ b/libraries/audio/src/AudioRingBuffer.h
@@ -21,6 +21,30 @@
 
 #include "NodeData.h"
 
+// this means that every 500 samples, the max for the past 10*500 samples will be calculated
+const int TIME_GAP_NUM_SAMPLES_IN_INTERVAL = 500;
+const int TIME_GAP_NUM_INTERVALS_IN_WINDOW = 10;
+
+class InterframeTimeGapHistory {
+public:
+    InterframeTimeGapHistory();
+
+    void frameReceived();
+    bool isNewWindowMaxGapAvailable() const { return _newWindowMaxGapAvailable; }
+    quint64 getPastWindowMaxGap();
+
+private:
+    quint64 _lastFrameReceivedTime;
+
+    int _numSamplesInCurrentInterval;
+    quint64 _currentIntervalMaxGap;
+    quint64 _intervalMaxGaps[TIME_GAP_NUM_INTERVALS_IN_WINDOW];
+    int _newestIntervalMaxGapAt;
+    quint64 _windowMaxGap;
+    bool _newWindowMaxGapAvailable;
+};
+
+
 const int SAMPLE_RATE = 24000;
 
 const int NETWORK_BUFFER_LENGTH_BYTES_STEREO = 1024;
@@ -74,6 +98,8 @@ public:
     bool hasStarted() const { return _hasStarted; }
     
     void addSilentFrame(int numSilentSamples);
+
+    InterframeTimeGapHistory& getInterframeTimeGapHistory() { return _timeGapHistory; }
 protected:
     // disallow copying of AudioRingBuffer objects
     AudioRingBuffer(const AudioRingBuffer&);
@@ -89,6 +115,8 @@ protected:
     bool _isStarved;
     bool _hasStarted;
     bool _randomAccessMode; /// will this ringbuffer be used for random access? if so, do some special processing
+
+    InterframeTimeGapHistory _timeGapHistory;
 };
 
 #endif // hifi_AudioRingBuffer_h
diff --git a/libraries/audio/src/InjectedAudioRingBuffer.cpp b/libraries/audio/src/InjectedAudioRingBuffer.cpp
index 2658b4c336..103d0d8d2e 100644
--- a/libraries/audio/src/InjectedAudioRingBuffer.cpp
+++ b/libraries/audio/src/InjectedAudioRingBuffer.cpp
@@ -31,6 +31,8 @@ InjectedAudioRingBuffer::InjectedAudioRingBuffer(const QUuid& streamIdentifier)
 const uchar MAX_INJECTOR_VOLUME = 255;
 
 int InjectedAudioRingBuffer::parseData(const QByteArray& packet) {
+    _timeGapHistory.frameReceived();
+
     // setup a data stream to read from this packet
     QDataStream packetStream(packet);
     packetStream.skipRawData(numBytesForPacketHeader(packet));