From ff5687c01ec3d93d4cdd4ed569a26250dfc41ef9 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Mon, 28 Sep 2015 12:37:09 -0700
Subject: [PATCH 1/8] GUAC-1354: Refactor Guacamole.AudioChannel to
 Guacamole.AudioPlayer.

---
 .../src/main/webapp/modules/AudioChannel.js   | 291 ------------
 .../src/main/webapp/modules/AudioPlayer.js    | 418 ++++++++++++++++++
 .../src/main/webapp/modules/Client.js         |  88 ++--
 3 files changed, 465 insertions(+), 332 deletions(-)
 delete mode 100644 guacamole-common-js/src/main/webapp/modules/AudioChannel.js
 create mode 100644 guacamole-common-js/src/main/webapp/modules/AudioPlayer.js

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioChannel.js b/guacamole-common-js/src/main/webapp/modules/AudioChannel.js
deleted file mode 100644
index 0f64c4d70..000000000
--- a/guacamole-common-js/src/main/webapp/modules/AudioChannel.js
+++ /dev/null
@@ -1,291 +0,0 @@
-/*
- * Copyright (C) 2015 Glyptodon LLC
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-var Guacamole = Guacamole || {};
-
-/**
- * Abstract audio channel which queues and plays arbitrary audio data.
- *
- * @constructor
- */
-Guacamole.AudioChannel = function AudioChannel() {
-
-    /**
-     * Reference to this AudioChannel.
-     *
-     * @private
-     * @type Guacamole.AudioChannel
-     */
-    var channel = this;
-
-    /**
-     * The earliest possible time that the next packet could play without
-     * overlapping an already-playing packet, in milliseconds.
-     *
-     * @private
-     * @type Number
-     */
-    var nextPacketTime = Guacamole.AudioChannel.getTimestamp();
-
-    /**
-     * The last time that sync() was called, in milliseconds. If sync() has
-     * never been called, this will be the time the Guacamole.AudioChannel
-     * was created.
-     *
-     * @type Number
-     */
-    var lastSync = nextPacketTime;
-
-    /**
-     * Notifies this Guacamole.AudioChannel that all audio up to the current
-     * point in time has been given via play(), and that any difference in time
-     * between queued audio packets and the current time can be considered
-     * latency.
-     */
-    this.sync = function sync() {
-
-        // Calculate elapsed time since last sync
-        var now = Guacamole.AudioChannel.getTimestamp();
-        var elapsed = now - lastSync;
-
-        // Reschedule future playback time such that playback latency is
-        // bounded within the duration of the last audio frame
-        nextPacketTime = Math.min(nextPacketTime, now + elapsed);
-
-        // Record sync time
-        lastSync = now;
-
-    };
-
-    /**
-     * Queues up the given data for playing by this channel once all previously
-     * queued data has been played. If no data has been queued, the data will
-     * play immediately.
-     * 
-     * @param {String} mimetype
-     *     The mimetype of the audio data provided.
-     *
-     * @param {Number} duration
-     *     The duration of the data provided, in milliseconds.
-     *
-     * @param {Blob} data
-     *     The blob of audio data to play.
-     */
-    this.play = function play(mimetype, duration, data) {
-
-        var packet = new Guacamole.AudioChannel.Packet(mimetype, data);
-
-        // Determine exactly when packet CAN play
-        var packetTime = Guacamole.AudioChannel.getTimestamp();
-        if (nextPacketTime < packetTime)
-            nextPacketTime = packetTime;
-
-        // Schedule packet
-        packet.play(nextPacketTime);
-
-        // Update timeline
-        nextPacketTime += duration;
-
-    };
-
-};
-
-// Define context if available
-if (window.AudioContext) {
-    try {Guacamole.AudioChannel.context = new AudioContext();}
-    catch (e){}
-}
-
-// Fallback to Webkit-specific AudioContext implementation
-else if (window.webkitAudioContext) {
-    try {Guacamole.AudioChannel.context = new webkitAudioContext();}
-    catch (e){}
-}
-
-/**
- * Returns a base timestamp which can be used for scheduling future audio
- * playback. Scheduling playback for the value returned by this function plus
- * N will cause the associated audio to be played back N milliseconds after
- * the function is called.
- *
- * @return {Number} An arbitrary channel-relative timestamp, in milliseconds.
- */
-Guacamole.AudioChannel.getTimestamp = function() {
-
-    // If we have an audio context, use its timestamp
-    if (Guacamole.AudioChannel.context)
-        return Guacamole.AudioChannel.context.currentTime * 1000;
-
-    // If we have high-resolution timers, use those
-    if (window.performance) {
-
-        if (window.performance.now)
-            return window.performance.now();
-
-        if (window.performance.webkitNow)
-            return window.performance.webkitNow();
-        
-    }
-
-    // Fallback to millisecond-resolution system time
-    return new Date().getTime();
-
-};
-
-/**
- * Abstract representation of an audio packet.
- * 
- * @constructor
- * 
- * @param {String} mimetype The mimetype of the data contained by this packet.
- * @param {Blob} data The blob of sound data contained by this packet.
- */
-Guacamole.AudioChannel.Packet = function(mimetype, data) {
-
-    /**
-     * Schedules this packet for playback at the given time.
-     *
-     * @function
-     * @param {Number} when The time this packet should be played, in
-     *                      milliseconds.
-     */
-    this.play = function(when) { /* NOP */ }; // Defined conditionally depending on support
-
-    // If audio API available, use it.
-    if (Guacamole.AudioChannel.context) {
-
-        var readyBuffer = null;
-
-        // By default, when decoding finishes, store buffer for future
-        // playback
-        var handleReady = function(buffer) {
-            readyBuffer = buffer;
-        };
-
-        // Read data and start decoding
-        var reader = new FileReader();
-        reader.onload = function() {
-            Guacamole.AudioChannel.context.decodeAudioData(
-                reader.result,
-                function(buffer) { handleReady(buffer); }
-            );
-        };
-        reader.readAsArrayBuffer(data);
-
-        // Set up buffer source
-        var source = Guacamole.AudioChannel.context.createBufferSource();
-        source.connect(Guacamole.AudioChannel.context.destination);
-
-        // Use noteOn() instead of start() if necessary
-        if (!source.start)
-            source.start = source.noteOn;
-
-        var play_when;
-
-        function playDelayed(buffer) {
-            source.buffer = buffer;
-            source.start(play_when / 1000);
-        }
-
-        /** @ignore */
-        this.play = function(when) {
-            
-            play_when = when;
-            
-            // If buffer available, play it NOW
-            if (readyBuffer)
-                playDelayed(readyBuffer);
-
-            // Otherwise, play when decoded
-            else
-                handleReady = playDelayed;
-
-        };
-
-    }
-
-    else {
-
-        var play_on_load = false;
-
-        // Create audio element to house and play the data
-        var audio = null;
-        try { audio = new Audio(); }
-        catch (e) {}
-
-        if (audio) {
-
-            // Read data and start decoding
-            var reader = new FileReader();
-            reader.onload = function() {
-
-                var binary = "";
-                var bytes = new Uint8Array(reader.result);
-
-                // Produce binary string from bytes in buffer
-                for (var i=0; i<bytes.byteLength; i++)
-                    binary += String.fromCharCode(bytes[i]);
-
-                // Convert to data URI 
-                audio.src = "data:" + mimetype + ";base64," + window.btoa(binary);
-
-                // Play if play was attempted but packet wasn't loaded yet
-                if (play_on_load)
-                    audio.play();
-
-            };
-            reader.readAsArrayBuffer(data);
-       
-            function play() {
-
-                // If audio data is ready, play now
-                if (audio.src)
-                    audio.play();
-
-                // Otherwise, play when loaded
-                else
-                    play_on_load = true;
-
-            }
-            
-            /** @ignore */
-            this.play = function(when) {
-                
-                // Calculate time until play
-                var now = Guacamole.AudioChannel.getTimestamp();
-                var delay = when - now;
-                
-                // Play now if too late
-                if (delay < 0)
-                    play();
-
-                // Otherwise, schedule later playback
-                else
-                    window.setTimeout(play, delay);
-
-            };
-
-        }
-
-    }
-
-};
diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
new file mode 100644
index 000000000..5c0eeeb90
--- /dev/null
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -0,0 +1,418 @@
+/*
+ * Copyright (C) 2015 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+var Guacamole = Guacamole || {};
+
+/**
+ * Abstract audio player which accepts, queues and plays back arbitrary audio
+ * data. It is up to implementations of this class to provide some means of
+ * handling a provided Guacamole.InputStream. Data received along the provided
+ * stream is to be played back immediately.
+ *
+ * @constructor
+ */
+Guacamole.AudioPlayer = function AudioPlayer() {
+
+    /**
+     * Notifies this Guacamole.AudioPlayer that all audio up to the current
+     * point in time has been given via the underlying stream, and that any
+     * difference in time between queued audio data and the current time can be
+     * considered latency.
+     */
+    this.sync = function sync() {
+        // Default implementation - do nothing
+    };
+
+};
+
+/**
+ * Returns a base timestamp which can be used for scheduling future audio
+ * playback. Scheduling playback for the value returned by this function plus
+ * N will cause the associated audio to be played back N milliseconds after
+ * the function is called.
+ *
+ * @return {Number}
+ *     An arbitrary relative timestamp, in milliseconds.
+ */
+Guacamole.AudioPlayer.getTimestamp = function() {
+
+    // If we have high-resolution timers, use those
+    if (window.performance) {
+        var now = performance.now || performance.webkitNow();
+        return now();
+    }
+
+    // Fallback to millisecond-resolution system time
+    return Date.now();
+
+};
+
+/**
+ * Implementation of Guacamole.AudioPlayer providing support for raw PCM format
+ * audio. This player relies only on the Web Audio API and does not require any
+ * browser-level support for its audio formats.
+ *
+ * @constructor
+ * @augments Guacamole.AudioPlayer
+ * @param {Guacamole.InputStream} stream
+ *     The Guacamole.InputStream to read audio data from.
+ *
+ * @param {String} mimetype
+ *     The mimetype of the audio data in the provided stream, which must be a
+ *     "audio/L8" or "audio/L16" mimetype with necessary parameters, such as:
+ *     "audio/L16;rate=44100,channels=2".
+ */
+Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
+
+    /**
+     * The format of audio this player will decode.
+     *
+     * @type Guacamole.RawAudioPlayer._Format
+     */
+    var format = Guacamole.RawAudioPlayer._Format.parse(mimetype);
+
+    /**
+     * An instance of a Web Audio API AudioContext object, or null if the
+     * Web Audio API is not supported.
+     *
+     * @type AudioContext
+     */
+    var context = (function getAudioContext() {
+
+        // Fallback to Webkit-specific AudioContext implementation
+        var AudioContext = window.AudioContext || window.webkitAudioContext;
+
+        // Get new AudioContext instance if Web Audio API is supported
+        if (AudioContext) {
+            try {
+                return new AudioContext();
+            }
+            catch (e) {
+                // Do not use Web Audio API if not allowed by browser
+            }
+        }
+
+        // Web Audio API not supported
+        return null;
+
+    })();
+
+    /**
+     * Returns a base timestamp which can be used for scheduling future audio
+     * playback. Scheduling playback for the value returned by this function plus
+     * N will cause the associated audio to be played back N milliseconds after
+     * the function is called.
+     *
+     * @return {Number}
+     *     An arbitrary relative timestamp, in milliseconds.
+     */
+    var getTimestamp = function getTimestamp() {
+
+        // If we have an audio context, use its timestamp
+        if (context)
+            return context.currentTime * 1000;
+
+        // Otherwise, use the internal timestamp implementation
+        return Guacamole.AudioPlayer.getTimestamp();
+
+    };
+
+    /**
+     * The earliest possible time that the next packet could play without
+     * overlapping an already-playing packet, in milliseconds.
+     *
+     * @private
+     * @type Number
+     */
+    var nextPacketTime = getTimestamp();
+
+    /**
+     * The last time that sync() was called, in milliseconds. If sync() has
+     * never been called, this will be the time the Guacamole.AudioPlayer
+     * was created.
+     *
+     * @type Number
+     */
+    var lastSync = nextPacketTime;
+
+    /**
+     * Guacamole.ArrayBufferReader wrapped around the audio input stream
+     * provided with this Guacamole.RawAudioPlayer was created.
+     *
+     * @type Guacamole.ArrayBufferReader
+     */
+    var reader = new Guacamole.ArrayBufferReader(stream);
+
+    // Play each received raw packet of audio immediately
+    reader.ondata = function playReceivedAudio(data) {
+
+        // Calculate total number of samples
+        var samples = data.byteLength / format.channels / format.bytesPerSample;
+
+        // Calculate overall duration (in milliseconds)
+        var duration = samples * 1000 / format.rate;
+
+        // Determine exactly when packet CAN play
+        var packetTime = getTimestamp();
+        if (nextPacketTime < packetTime)
+            nextPacketTime = packetTime;
+
+        // Obtain typed array view based on defined bytes per sample
+        var maxValue;
+        var source;
+        if (format.bytesPerSample === 1) {
+            source = new Int8Array(data);
+            maxValue = 128;
+        }
+        else {
+            source = new Int16Array(data);
+            maxValue = 32768;
+        }
+
+        // Get audio buffer for specified format
+        var audioBuffer = context.createBuffer(format.channels, samples, format.rate);
+
+        // Convert each channel
+        for (var channel = 0; channel < format.channels; channel++) {
+
+            var audioData = audioBuffer.getChannelData(channel);
+
+            // Fill audio buffer with data for channel
+            var offset = channel;
+            for (var i = 0; i < samples; i++) {
+                audioData[i] = source[offset] / maxValue;
+                offset += format.channels;
+            }
+
+        }
+
+        // Set up buffer source
+        var source = context.createBufferSource();
+        source.connect(context.destination);
+
+        // Use noteOn() instead of start() if necessary
+        if (!source.start)
+            source.start = source.noteOn;
+
+        // Schedule packet
+        source.buffer = audioBuffer;
+        source.start(nextPacketTime / 1000);
+
+        // Update timeline
+        nextPacketTime += duration;
+
+    };
+
+    /** @override */
+    this.sync = function sync() {
+
+        // Calculate elapsed time since last sync
+        var now = getTimestamp();
+        var elapsed = now - lastSync;
+
+        // Reschedule future playback time such that playback latency is
+        // bounded within the duration of the last audio frame
+        nextPacketTime = Math.min(nextPacketTime, now + elapsed);
+
+        // Record sync time
+        lastSync = now;
+
+    };
+
+};
+
+Guacamole.RawAudioPlayer.prototype = new Guacamole.AudioPlayer();
+
+/**
+ * A description of the format of raw PCM audio received by a
+ * Guacamole.RawAudioPlayer. This object describes the number of bytes per
+ * sample, the number of channels, and the overall sample rate.
+ *
+ * @private
+ * @constructor
+ * @param {Guacamole.RawAudioPlayer._Format|Object} template
+ *     The object whose properties should be copied into the corresponding
+ *     properties of the new Guacamole.RawAudioPlayer._Format.
+ */
+Guacamole.RawAudioPlayer._Format = function _Format(template) {
+
+    /**
+     * The number of bytes in each sample of audio data. This value is
+     * independent of the number of channels.
+     *
+     * @type Number
+     */
+    this.bytesPerSample = template.bytesPerSample;
+
+    /**
+     * The number of audio channels (ie: 1 for mono, 2 for stereo).
+     *
+     * @type Number
+     */
+    this.channels = template.channels;
+
+    /**
+     * The number of samples per second, per channel.
+     *
+     * @type Number
+     */
+    this.rate = template.rate;
+
+};
+
+/**
+ * Parses the given mimetype, returning a new Guacamole.RawAudioPlayer._Format
+ * which describes the type of raw audio data represented by that mimetype. If
+ * the mimetype is not supported by Guacamole.RawAudioPlayer, null is returned.
+ *
+ * @private
+ * @param {String} mimetype
+ *     The audio mimetype to parse.
+ *
+ * @returns {Guacamole.RawAudioPlayer._Format}
+ *     A new Guacamole.RawAudioPlayer._Format which describes the type of raw
+ *     audio data represented by the given mimetype, or null if the given
+ *     mimetype is not supported.
+ */
+Guacamole.RawAudioPlayer._Format.parse = function parseFormat(mimetype) {
+
+    var bytesPerSample;
+
+    // Rate is absolutely required - if null is still present later, the
+    // mimetype must not be supported
+    var rate = null;
+
+    // Default for both "audio/L8" and "audio/L16" is one channel
+    var channels = 1;
+
+    // "audio/L8" has one byte per sample
+    if (mimetype.substring(0, 9) === 'audio/L8;') {
+        mimetype = mimetype.substring(9);
+        bytesPerSample = 1;
+    }
+
+    // "audio/L16" has two bytes per sample
+    else if (mimetype.substring(0, 10) === 'audio/L16;') {
+        mimetype = mimetype.substring(10);
+        bytesPerSample = 2;
+    }
+
+    // All other types are unsupported
+    else
+        return null;
+
+    // Parse all parameters
+    var parameters = mimetype.split(',');
+    for (var i = 0; i < parameters.length; i++) {
+
+        var parameter = parameters[i];
+
+        // All parameters must have an equals sign separating name from value
+        var equals = parameter.indexOf('=');
+        if (equals === -1)
+            return null;
+
+        // Parse name and value from parameter string
+        var name  = parameter.substring(0, equals);
+        var value = parameter.substring(equals+1);
+
+        // Handle each supported parameter
+        switch (name) {
+
+            // Number of audio channels
+            case 'channels':
+                channels = parseInt(value);
+                break;
+
+            // Sample rate
+            case 'rate':
+                rate = parseInt(value);
+                break;
+
+            // All other parameters are unsupported
+            default:
+                return null;
+
+        }
+
+    };
+
+    // The rate parameter is required
+    if (rate === null)
+        return null;
+
+    // Return parsed format details
+    return new Guacamole.RawAudioPlayer._Format({
+        bytesPerSample : bytesPerSample,
+        channels       : channels,
+        rate           : rate
+    });
+
+};
+
+/**
+ * Determines whether the given mimetype is supported by
+ * Guacamole.RawAudioPlayer.
+ *
+ * @param {String} mimetype
+ *     The mimetype to check.
+ *
+ * @returns {Boolean}
+ *     true if the given mimetype is supported by Guacamole.RawAudioPlayer,
+ *     false otherwise.
+ */
+Guacamole.RawAudioPlayer.isSupportedType = function isSupportedType(mimetype) {
+
+    // No supported types if no Web Audio API
+    if (!window.AudioContext && !window.webkitAudioContext)
+        return false;
+
+    return Guacamole.RawAudioPlayer._Format.parse(mimetype) !== null;
+
+};
+
+/**
+ * Returns a list of all mimetypes supported by Guacamole.RawAudioPlayer. Only
+ * the core mimetypes themselves will be listed. Any mimetype parameters, even
+ * required ones, will not be included in the list. For example, "audio/L8" is
+ * a raw audio mimetype that may be supported, but it is invalid without
+ * additional parameters. Something like "audio/L8;rate=44100" would be valid,
+ * however (see https://tools.ietf.org/html/rfc4856).
+ *
+ * @returns {String[]}
+ *     A list of all mimetypes supported by Guacamole.RawAudioPlayer, excluding
+ *     any parameters. If the necessary JavaScript APIs for playing raw audio
+ *     are absent, this list will be empty.
+ */
+Guacamole.RawAudioPlayer.getSupportedTypes = function getSupportedTypes() {
+
+    // No supported types if no Web Audio API
+    if (!window.AudioContext && !window.webkitAudioContext)
+        return [];
+
+    // We support 8-bit and 16-bit raw PCM
+    return [
+        'audio/L8',
+        'audio/L16'
+    ];
+
+};
diff --git a/guacamole-common-js/src/main/webapp/modules/Client.js b/guacamole-common-js/src/main/webapp/modules/Client.js
index c3546cd9b..8104159d4 100644
--- a/guacamole-common-js/src/main/webapp/modules/Client.js
+++ b/guacamole-common-js/src/main/webapp/modules/Client.js
@@ -78,12 +78,12 @@ Guacamole.Client = function(tunnel) {
     var layers = {};
     
     /**
-     * All audio channels currentl in use by the client. Initially, this will
-     * be empty, but channels may be allocated by the server upon request.
+     * All audio players currently in use by the client. Initially, this will
+     * be empty, but audio players may be allocated by the server upon request.
      *
-     * @type Object.<Number, Guacamole.AudioChannel>
+     * @type Object.<Number, Guacamole.AudioPlayer>
      */
-    var audioChannels = {};
+    var audioPlayers = {};
 
     // No initial parsers
     var parsers = [];
@@ -440,6 +440,25 @@ Guacamole.Client = function(tunnel) {
      */
     this.onerror = null;
 
+    /**
+     * Fired when a audio stream is created. The stream provided to this event
+     * handler will contain its own event handlers for received data.
+     *
+     * @event
+     * @param {Guacamole.InputStream} stream
+     *     The stream that will receive audio data from the server.
+     *
+     * @param {String} mimetype
+     *     The mimetype of the audio data which will be received.
+     *
+     * @return {Guacamole.AudioPlayer}
+     *     An object which implements the Guacamole.AudioPlayer interface and
+     *     has been initialied to play the data in the provided stream, or null
+     *     if the built-in audio players of the Guacamole client should be
+     *     used.
+     */
+    this.onaudio = null;
+
     /**
      * Fired when the clipboard of the remote client is changing.
      * 
@@ -499,27 +518,6 @@ Guacamole.Client = function(tunnel) {
      */
     this.onsync = null;
 
-    /**
-     * Returns the audio channel having the given index, creating a new channel
-     * if necessary.
-     *
-     * @param {Number} index
-     *     The index of the audio channel to retrieve.
-     *
-     * @returns {Guacamole.AudioChannel}
-     *     The audio channel having the given index.
-     */
-    var getAudioChannel = function getAudioChannel(index) {
-
-        // Get audio channel, creating it first if necessary
-        var audio_channel = audioChannels[index];
-        if (!audio_channel)
-            audio_channel = audioChannels[index] = new Guacamole.AudioChannel();
-
-        return audio_channel;
-
-    };
-
     /**
      * Returns the layer with the given index, creating it if necessary.
      * Positive indices refer to visible layers, an index of zero refers to
@@ -626,24 +624,32 @@ Guacamole.Client = function(tunnel) {
         "audio": function(parameters) {
 
             var stream_index = parseInt(parameters[0]);
-            var channel = getAudioChannel(parseInt(parameters[1]));
-            var mimetype = parameters[2];
-            var duration = parseFloat(parameters[3]);
+            var mimetype = parameters[1];
 
             // Create stream 
             var stream = streams[stream_index] =
                     new Guacamole.InputStream(guac_client, stream_index);
 
-            // Assemble entire stream as a blob
-            var blob_reader = new Guacamole.BlobReader(stream, mimetype);
+            // Get player instance via callback
+            var audioPlayer = null;
+            if (guac_client.onaudio)
+                audioPlayer = guac_client.onaudio(stream, mimetype);
 
-            // Play blob as audio
-            blob_reader.onend = function() {
-                channel.play(mimetype, duration, blob_reader.getBlob());
-            };
+            // If unsuccessful, use a default implementation
+            if (!audioPlayer) {
+                if (Guacamole.RawAudioPlayer.isSupportedType(mimetype))
+                    audioPlayer = new Guacamole.RawAudioPlayer(stream, mimetype);
+            }
 
-            // Send success response
-            guac_client.sendAck(stream_index, "OK", 0x0000);
+            // If player somehow successfully retrieved, send success response
+            if (audioPlayer) {
+                audioPlayers[stream_index] = audioPlayer;
+                guac_client.sendAck(stream_index, "OK", 0x0000);
+            }
+
+            // Otherwise, mimetype must be unsupported
+            else
+                guac_client.sendAck(stream_index, "BAD TYPE", 0x030F);
 
         },
 
@@ -1113,11 +1119,11 @@ Guacamole.Client = function(tunnel) {
             // Flush display, send sync when done
             display.flush(function displaySyncComplete() {
 
-                // Synchronize all audio channels
-                for (var index in audioChannels) {
-                    var audioChannel = audioChannels[index];
-                    if (audioChannel)
-                        audioChannel.sync();
+                // Synchronize all audio players
+                for (var index in audioPlayers) {
+                    var audioPlayer = audioPlayers[index];
+                    if (audioPlayer)
+                        audioPlayer.sync();
                 }
 
                 // Send sync response to server

From df57eac616955478d172c4e81f126faef7fc8883 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Mon, 28 Sep 2015 13:23:40 -0700
Subject: [PATCH 2/8] GUAC-1354: Use past audio packet size to determine
 playback latency threshold for audio. Add missing private annotations.

---
 .../src/main/webapp/modules/AudioPlayer.js    | 34 +++++++++++--------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index 5c0eeeb90..abda411d0 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -86,6 +86,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
     /**
      * The format of audio this player will decode.
      *
+     * @private
      * @type Guacamole.RawAudioPlayer._Format
      */
     var format = Guacamole.RawAudioPlayer._Format.parse(mimetype);
@@ -94,6 +95,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
      * An instance of a Web Audio API AudioContext object, or null if the
      * Web Audio API is not supported.
      *
+     * @private
      * @type AudioContext
      */
     var context = (function getAudioContext() {
@@ -122,6 +124,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
      * N will cause the associated audio to be played back N milliseconds after
      * the function is called.
      *
+     * @private
      * @return {Number}
      *     An arbitrary relative timestamp, in milliseconds.
      */
@@ -145,23 +148,25 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
      */
     var nextPacketTime = getTimestamp();
 
-    /**
-     * The last time that sync() was called, in milliseconds. If sync() has
-     * never been called, this will be the time the Guacamole.AudioPlayer
-     * was created.
-     *
-     * @type Number
-     */
-    var lastSync = nextPacketTime;
-
     /**
      * Guacamole.ArrayBufferReader wrapped around the audio input stream
      * provided with this Guacamole.RawAudioPlayer was created.
      *
+     * @private
      * @type Guacamole.ArrayBufferReader
      */
     var reader = new Guacamole.ArrayBufferReader(stream);
 
+    /**
+     * The maximum amount of latency to allow between the buffered data stream
+     * and the playback position, in milliseconds. Initially, this is set to
+     * roughly one third of a second, but it will be recalculated dynamically.
+     *
+     * @private
+     * @type Number
+     */
+    var maxLatency = 300;
+
     // Play each received raw packet of audio immediately
     reader.ondata = function playReceivedAudio(data) {
 
@@ -171,6 +176,9 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
         // Calculate overall duration (in milliseconds)
         var duration = samples * 1000 / format.rate;
 
+        // Recalculate latency threshold based on packet size
+        maxLatency = duration * 2;
+
         // Determine exactly when packet CAN play
         var packetTime = getTimestamp();
         if (nextPacketTime < packetTime)
@@ -227,14 +235,10 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
 
         // Calculate elapsed time since last sync
         var now = getTimestamp();
-        var elapsed = now - lastSync;
 
         // Reschedule future playback time such that playback latency is
-        // bounded within the duration of the last audio frame
-        nextPacketTime = Math.min(nextPacketTime, now + elapsed);
-
-        // Record sync time
-        lastSync = now;
+        // bounded within a reasonable latency threshold
+        nextPacketTime = Math.min(nextPacketTime, now + maxLatency);
 
     };
 

From f0e6da86c9b0268b18e224851b2f5da5eee1ef68 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Wed, 30 Sep 2015 17:02:18 -0700
Subject: [PATCH 3/8] GUAC-1354: Use Guacamole.AudioPlayer.getInstance(), etc.
 to abstract away the various implementations.

---
 .../src/main/webapp/modules/AudioPlayer.js    | 64 +++++++++++++++++++
 .../src/main/webapp/modules/Client.js         | 10 ++-
 2 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index abda411d0..08bf4c82c 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -66,6 +66,70 @@ Guacamole.AudioPlayer.getTimestamp = function() {
 
 };
 
+/**
+ * Determines whether the given mimetype is supported by any built-in
+ * implementation of Guacamole.AudioPlayer, and thus will be properly handled
+ * by Guacamole.AudioPlayer.getInstance().
+ *
+ * @param {String} mimetype
+ *     The mimetype to check.
+ *
+ * @returns {Boolean}
+ *     true if the given mimetype is supported by any built-in
+ *     Guacamole.AudioPlayer, false otherwise.
+ */
+Guacamole.AudioPlayer.isSupportedType = function isSupportedType(mimetype) {
+
+    return Guacamole.RawAudioPlayer.isSupportedType(mimetype);
+
+};
+
+/**
+ * Returns a list of all mimetypes supported by any built-in
+ * Guacamole.AudioPlayer, in rough order of priority. Beware that only the core
+ * mimetypes themselves will be listed. Any mimetype parameters, even required
+ * ones, will not be included in the list. For example, "audio/L8" is a
+ * supported raw audio mimetype that is supported, but it is invalid without
+ * additional parameters. Something like "audio/L8;rate=44100" would be valid,
+ * however (see https://tools.ietf.org/html/rfc4856).
+ *
+ * @returns {String[]}
+ *     A list of all mimetypes supported by any built-in Guacamole.AudioPlayer,
+ *     excluding any parameters.
+ */
+Guacamole.AudioPlayer.getSupportedTypes = function getSupportedTypes() {
+
+    return Guacamole.RawAudioPlayer.getSupportedTypes();
+
+};
+
+/**
+ * Returns an instance of Guacamole.AudioPlayer providing support for the given
+ * audio format. If support for the given audio format is not available, null
+ * is returned.
+ *
+ * @param {Guacamole.InputStream} stream
+ *     The Guacamole.InputStream to read audio data from.
+ *
+ * @param {String} mimetype
+ *     The mimetype of the audio data in the provided stream.
+ *
+ * @return {Guacamole.AudioPlayer}
+ *     A Guacamole.AudioPlayer instance supporting the given mimetype and
+ *     reading from the given stream, or null if support for the given mimetype
+ *     is absent.
+ */
+Guacamole.AudioPlayer.getInstance = function getInstance(stream, mimetype) {
+
+    // Use raw audio player if possible
+    if (Guacamole.RawAudioPlayer.isSupportedType(mimetype))
+        return new Guacamole.RawAudioPlayer(stream, mimetype);
+
+    // No support for given mimetype
+    return null;
+
+};
+
 /**
  * Implementation of Guacamole.AudioPlayer providing support for raw PCM format
  * audio. This player relies only on the Web Audio API and does not require any
diff --git a/guacamole-common-js/src/main/webapp/modules/Client.js b/guacamole-common-js/src/main/webapp/modules/Client.js
index 8104159d4..894888738 100644
--- a/guacamole-common-js/src/main/webapp/modules/Client.js
+++ b/guacamole-common-js/src/main/webapp/modules/Client.js
@@ -635,13 +635,11 @@ Guacamole.Client = function(tunnel) {
             if (guac_client.onaudio)
                 audioPlayer = guac_client.onaudio(stream, mimetype);
 
-            // If unsuccessful, use a default implementation
-            if (!audioPlayer) {
-                if (Guacamole.RawAudioPlayer.isSupportedType(mimetype))
-                    audioPlayer = new Guacamole.RawAudioPlayer(stream, mimetype);
-            }
+            // If unsuccessful, try to use a default implementation
+            if (!audioPlayer)
+                audioPlayer = Guacamole.AudioPlayer.getInstance(stream, mimetype);
 
-            // If player somehow successfully retrieved, send success response
+            // If we have successfully retrieved an audio player, send success response
             if (audioPlayer) {
                 audioPlayers[stream_index] = audioPlayer;
                 guac_client.sendAck(stream_index, "OK", 0x0000);

From 572534c6d336d3e68bdb2a548d0854ac84499b8f Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Wed, 30 Sep 2015 17:06:23 -0700
Subject: [PATCH 4/8] GUAC-1354: Use Web Audio API timestamps directly - no
 need to convert to milliseconds and back.

---
 .../src/main/webapp/modules/AudioPlayer.js    | 63 ++++---------------
 1 file changed, 11 insertions(+), 52 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index 08bf4c82c..98a3592aa 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -44,28 +44,6 @@ Guacamole.AudioPlayer = function AudioPlayer() {
 
 };
 
-/**
- * Returns a base timestamp which can be used for scheduling future audio
- * playback. Scheduling playback for the value returned by this function plus
- * N will cause the associated audio to be played back N milliseconds after
- * the function is called.
- *
- * @return {Number}
- *     An arbitrary relative timestamp, in milliseconds.
- */
-Guacamole.AudioPlayer.getTimestamp = function() {
-
-    // If we have high-resolution timers, use those
-    if (window.performance) {
-        var now = performance.now || performance.webkitNow();
-        return now();
-    }
-
-    // Fallback to millisecond-resolution system time
-    return Date.now();
-
-};
-
 /**
  * Determines whether the given mimetype is supported by any built-in
  * implementation of Guacamole.AudioPlayer, and thus will be properly handled
@@ -182,35 +160,16 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
 
     })();
 
-    /**
-     * Returns a base timestamp which can be used for scheduling future audio
-     * playback. Scheduling playback for the value returned by this function plus
-     * N will cause the associated audio to be played back N milliseconds after
-     * the function is called.
-     *
-     * @private
-     * @return {Number}
-     *     An arbitrary relative timestamp, in milliseconds.
-     */
-    var getTimestamp = function getTimestamp() {
-
-        // If we have an audio context, use its timestamp
-        if (context)
-            return context.currentTime * 1000;
-
-        // Otherwise, use the internal timestamp implementation
-        return Guacamole.AudioPlayer.getTimestamp();
-
-    };
-
     /**
      * The earliest possible time that the next packet could play without
-     * overlapping an already-playing packet, in milliseconds.
+     * overlapping an already-playing packet, in seconds. Note that while this
+     * value is in seconds, it is not an integer value and has microsecond
+     * resolution.
      *
      * @private
      * @type Number
      */
-    var nextPacketTime = getTimestamp();
+    var nextPacketTime = context.currentTime;
 
     /**
      * Guacamole.ArrayBufferReader wrapped around the audio input stream
@@ -223,13 +182,13 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
 
     /**
      * The maximum amount of latency to allow between the buffered data stream
-     * and the playback position, in milliseconds. Initially, this is set to
+     * and the playback position, in seconds. Initially, this is set to
      * roughly one third of a second, but it will be recalculated dynamically.
      *
      * @private
      * @type Number
      */
-    var maxLatency = 300;
+    var maxLatency = 0.3;
 
     // Play each received raw packet of audio immediately
     reader.ondata = function playReceivedAudio(data) {
@@ -237,14 +196,14 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
         // Calculate total number of samples
         var samples = data.byteLength / format.channels / format.bytesPerSample;
 
-        // Calculate overall duration (in milliseconds)
-        var duration = samples * 1000 / format.rate;
+        // Calculate overall duration (in seconds)
+        var duration = samples / format.rate;
 
         // Recalculate latency threshold based on packet size
         maxLatency = duration * 2;
 
         // Determine exactly when packet CAN play
-        var packetTime = getTimestamp();
+        var packetTime = context.currentTime;
         if (nextPacketTime < packetTime)
             nextPacketTime = packetTime;
 
@@ -287,7 +246,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
 
         // Schedule packet
         source.buffer = audioBuffer;
-        source.start(nextPacketTime / 1000);
+        source.start(nextPacketTime);
 
         // Update timeline
         nextPacketTime += duration;
@@ -298,7 +257,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
     this.sync = function sync() {
 
         // Calculate elapsed time since last sync
-        var now = getTimestamp();
+        var now = context.currentTime;
 
         // Reschedule future playback time such that playback latency is
         // bounded within a reasonable latency threshold

From 324c800167765b0fbe09dcbdb5ca3f546892ba53 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Wed, 30 Sep 2015 17:07:14 -0700
Subject: [PATCH 5/8] GUAC-1354: Use Guacamole.AudioPlayer.getSupportedTypes()
 to query available audio mimetypes within webapp.

---
 .../webapp/app/client/services/guacAudio.js   | 77 +------------------
 1 file changed, 3 insertions(+), 74 deletions(-)

diff --git a/guacamole/src/main/webapp/app/client/services/guacAudio.js b/guacamole/src/main/webapp/app/client/services/guacAudio.js
index 061820584..bacc62842 100644
--- a/guacamole/src/main/webapp/app/client/services/guacAudio.js
+++ b/guacamole/src/main/webapp/app/client/services/guacAudio.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014 Glyptodon LLC
+ * Copyright (C) 2015 Glyptodon LLC
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -31,82 +31,11 @@ angular.module('client').factory('guacAudio', [function guacAudio() {
     return new (function() {
 
         /**
-         * Array of codecs to test.
+         * Array of all supported audio mimetypes.
          *
          * @type String[]
          */
-        var codecs = [
-            'audio/ogg; codecs="vorbis"',
-            'audio/mp4; codecs="mp4a.40.5"',
-            'audio/mpeg; codecs="mp3"',
-            'audio/webm; codecs="vorbis"',
-            'audio/wav; codecs=1'
-        ];
-
-        /**
-         * Array of all codecs that are reported as "probably" supported.
-         *
-         * @type String[]
-         */
-        var probably_supported = [];
-
-        /**
-         * Array of all codecs that are reported as "maybe" supported.
-         *
-         * @type String[]
-         */
-        var maybe_supported = [];
-
-        /**
-         * Internal audio element for the sake of testing codec support. If
-         * audio is explicitly not supported by the browser, this will instead
-         * be null.
-         *
-         * @type Audio
-         */
-        var audio = null;
-
-        // Attempt to create audio element
-        try {
-            audio = new Audio();
-        }
-        catch (e) {
-            // If creation fails, allow audio to remain null
-        }
-
-        /**
-         * Array of all supported audio mimetypes, ordered by liklihood of
-         * working.
-         */
-        this.supported = [];
-
-        // Build array of supported audio formats (if audio supported at all)
-        if (audio) {
-            codecs.forEach(function(mimetype) {
-
-                var support_level = audio.canPlayType(mimetype);
-
-                // Trim semicolon and trailer
-                var semicolon = mimetype.indexOf(";");
-                if (semicolon !== -1)
-                    mimetype = mimetype.substring(0, semicolon);
-
-                // Partition by probably/maybe
-                if (support_level === "probably")
-                    probably_supported.push(mimetype);
-                else if (support_level === "maybe")
-                    maybe_supported.push(mimetype);
-
-            });
-
-            // Add probably supported types first
-            Array.prototype.push.apply(
-                this.supported, probably_supported);
-
-            // Prioritize "maybe" supported types second
-            Array.prototype.push.apply(
-                this.supported, maybe_supported);
-        }
+        this.supported = Guacamole.AudioPlayer.getSupportedTypes();
 
     })();
 

From a3dd959dc41c0aafcaeb8f17694741b5f7ab4e48 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Wed, 30 Sep 2015 17:11:54 -0700
Subject: [PATCH 6/8] GUAC-1354: Do not recalculate max latency using packet
 duration. Audio packet duration will ALWAYS be roughly the same due to the
 max blob size.

---
 guacamole-common-js/src/main/webapp/modules/AudioPlayer.js | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index 98a3592aa..938c04318 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -183,7 +183,7 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
     /**
      * The maximum amount of latency to allow between the buffered data stream
      * and the playback position, in seconds. Initially, this is set to
-     * roughly one third of a second, but it will be recalculated dynamically.
+     * roughly one third of a second.
      *
      * @private
      * @type Number
@@ -199,9 +199,6 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
         // Calculate overall duration (in seconds)
         var duration = samples / format.rate;
 
-        // Recalculate latency threshold based on packet size
-        maxLatency = duration * 2;
-
         // Determine exactly when packet CAN play
         var packetTime = context.currentTime;
         if (nextPacketTime < packetTime)

From 079e3dad8c1df3e5ce4c0aba3f6b186461e0ace5 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Fri, 2 Oct 2015 16:42:24 -0700
Subject: [PATCH 7/8] GUAC-1354: Dynamically split and reassemble audio packets
 to minimize clicking.

---
 .../src/main/webapp/modules/AudioPlayer.js    | 254 ++++++++++++++++--
 1 file changed, 232 insertions(+), 22 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index 938c04318..98b3189ba 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -180,6 +180,18 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
      */
     var reader = new Guacamole.ArrayBufferReader(stream);
 
+    /**
+     * The minimum size of an audio packet split by splitAudioPacket(), in
+     * seconds. Audio packets smaller than this will not be split, nor will the
+     * split result of a larger packet ever be smaller in size than this
+     * minimum.
+     *
+     * @private
+     * @constant
+     * @type Number
+     */
+    var MIN_SPLIT_SIZE = 0.02;
+
     /**
      * The maximum amount of latency to allow between the buffered data stream
      * and the playback position, in seconds. Initially, this is set to
@@ -190,32 +202,209 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
      */
     var maxLatency = 0.3;
 
-    // Play each received raw packet of audio immediately
-    reader.ondata = function playReceivedAudio(data) {
+    /**
+     * The type of typed array that will be used to represent each audio packet
+     * internally. This will be either Int8Array or Int16Array, depending on
+     * whether the raw audio format is 8-bit or 16-bit.
+     *
+     * @private
+     * @constructor
+     */
+    var SampleArray = (format.bytesPerSample === 1) ? window.Int8Array : window.Int16Array;
+
+    /**
+     * The maximum absolute value of any sample within a raw audio packet
+     * received by this audio player. This depends only on the size of each
+     * sample, and will be 128 for 8-bit audio and 32768 for 16-bit audio.
+     *
+     * @private
+     * @type Number
+     */
+    var maxSampleValue = (format.bytesPerSample === 1) ? 128 : 32768;
+
+    /**
+     * The queue of all pending audio packets, as an array of sample arrays.
+     * Audio packets which are pending playback will be added to this queue for
+     * further manipulation prior to scheduling via the Web Audio API. Once an
+     * audio packet leaves this queue and is scheduled via the Web Audio API,
+     * no further modifications can be made to that packet.
+     *
+     * @private
+     * @type SampleArray[]
+     */
+    var packetQueue = [];
+
+    /**
+     * Given an array of audio packets, returns a single audio packet
+     * containing the concatenation of those packets.
+     *
+     * @private
+     * @param {SampleArray[]} packets
+     *     The array of audio packets to concatenate.
+     *
+     * @returns {SampleArray}
+     *     A single audio packet containing the concatenation of all given
+     *     audio packets. If no packets are provided, this will be undefined.
+     */
+    var joinAudioPackets = function joinAudioPackets(packets) {
+
+        // Do not bother joining if one or fewer packets are in the queue
+        if (packets.length <= 1)
+            return packets[0];
+
+        // Determine total sample length of the entire queue
+        var totalLength = 0;
+        packets.forEach(function addPacketLengths(packet) {
+            totalLength += packet.length;
+        });
+
+        // Append each packet within queue
+        var offset = 0;
+        var joined = new SampleArray(totalLength);
+        packets.forEach(function appendPacket(packet) {
+            joined.set(packet, offset);
+            offset += packet.length;
+        });
+
+        return joined;
+
+    };
+
+    /**
+     * Given a single packet of audio data, splits off an arbitrary length of
+     * audio data from the beginning of that packet, returning the split result
+     * as an array of two packets. The split location is determined through an
+     * algorithm intended to minimize the liklihood of audible clicking between
+     * packets. If no such split location is possible, an array containing only
+     * the originally-provided audio packet is returned.
+     *
+     * @private
+     * @param {SampleArray} data
+     *     The audio packet to split.
+     *
+     * @returns {SampleArray[]}
+     *     An array of audio packets containing the result of splitting the
+     *     provided audio packet. If splitting is possible, this array will
+     *     contain two packets. If splitting is not possible, this array will
+     *     contain only the originally-provided packet.
+     */
+    var splitAudioPacket = function splitAudioPacket(data) {
+
+        var minValue = Number.MAX_VALUE;
+        var optimalSplitLength = data.length;
+
+        // Calculate number of whole samples in the provided audio packet AND
+        // in the minimum possible split packet
+        var samples = Math.floor(data.length / format.channels);
+        var minSplitSamples = Math.floor(format.rate * MIN_SPLIT_SIZE);
+
+        // Calculate the beginning of the "end" of the audio packet
+        var start = Math.max(
+            format.channels * minSplitSamples,
+            format.channels * (samples - minSplitSamples)
+        );
+
+        // For all samples at the end of the given packet, find a point where
+        // the perceptible volume across all channels is lowest (and thus is
+        // the optimal point to split)
+        for (var offset = start; offset < data.length; offset += format.channels) {
+
+            // Calculate the sum of all values across all channels (the result
+            // will be proportional to the average volume of a sample)
+            var totalValue = 0;
+            for (var channel = 0; channel < format.channels; channel++) {
+                totalValue += Math.abs(data[offset + channel]);
+            }
+
+            // If this is the smallest average value thus far, set the split
+            // length such that the first packet ends with the current sample
+            if (totalValue <= minValue) {
+                optimalSplitLength = offset + format.channels;
+                minValue = totalValue;
+            }
+
+        }
+
+        // If packet is not split, return the supplied packet untouched
+        if (optimalSplitLength === data.length)
+            return [data];
+
+        // Otherwise, split the packet into two new packets according to the
+        // calculated optimal split length
+        return [
+            data.slice(0, optimalSplitLength),
+            data.slice(optimalSplitLength)
+        ];
+
+    };
+
+    /**
+     * Pushes the given packet of audio data onto the playback queue. Unlike
+     * other private functions within Guacamole.RawAudioPlayer, the type of the
+     * ArrayBuffer packet of audio data here need not be specific to the type
+     * of audio (as with SampleArray). The ArrayBuffer type provided by a
+     * Guacamole.ArrayBufferReader, for example, is sufficient. Any necessary
+     * conversions will be performed automatically internally.
+     *
+     * @private
+     * @param {ArrayBuffer} data
+     *     A raw packet of audio data that should be pushed onto the audio
+     *     playback queue.
+     */
+    var pushAudioPacket = function pushAudioPacket(data) {
+        packetQueue.push(new SampleArray(data));
+    };
+
+    /**
+     * Shifts off and returns a packet of audio data from the beginning of the
+     * playback queue. The length of this audio packet is determined
+     * dynamically according to the click-reduction algorithm implemented by
+     * splitAudioPacket().
+     *
+     * @returns {SampleArray}
+     *     A packet of audio data pulled from the beginning of the playback
+     *     queue.
+     */
+    var shiftAudioPacket = function shiftAudioPacket() {
+
+        // Flatten data in packet queue
+        var data = joinAudioPackets(packetQueue);
+        if (!data)
+            return null;
+
+        // Pull an appropriate amount of data from the front of the queue
+        packetQueue = splitAudioPacket(data);
+        data = packetQueue.shift();
+
+        return data;
+
+    };
+
+    /**
+     * Converts the given audio packet into an AudioBuffer, ready for playback
+     * by the Web Audio API. Unlike the raw audio packets received by this
+     * audio player, AudioBuffers require floating point samples and are split
+     * into isolated planes of channel-specific data.
+     *
+     * @private
+     * @param {SampleArray} data
+     *     The raw audio packet that should be converted into a Web Audio API
+     *     AudioBuffer.
+     *
+     * @returns {AudioBuffer}
+     *     A new Web Audio API AudioBuffer containing the provided audio data,
+     *     converted to the format used by the Web Audio API.
+     */
+    var toAudioBuffer = function toAudioBuffer(data) {
 
         // Calculate total number of samples
-        var samples = data.byteLength / format.channels / format.bytesPerSample;
-
-        // Calculate overall duration (in seconds)
-        var duration = samples / format.rate;
+        var samples = data.length / format.channels;
 
         // Determine exactly when packet CAN play
         var packetTime = context.currentTime;
         if (nextPacketTime < packetTime)
             nextPacketTime = packetTime;
 
-        // Obtain typed array view based on defined bytes per sample
-        var maxValue;
-        var source;
-        if (format.bytesPerSample === 1) {
-            source = new Int8Array(data);
-            maxValue = 128;
-        }
-        else {
-            source = new Int16Array(data);
-            maxValue = 32768;
-        }
-
         // Get audio buffer for specified format
         var audioBuffer = context.createBuffer(format.channels, samples, format.rate);
 
@@ -227,12 +416,33 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
             // Fill audio buffer with data for channel
             var offset = channel;
             for (var i = 0; i < samples; i++) {
-                audioData[i] = source[offset] / maxValue;
+                audioData[i] = data[offset] / maxSampleValue;
                 offset += format.channels;
             }
 
         }
 
+        return audioBuffer;
+
+    };
+
+    // Defer playback of received audio packets slightly
+    reader.ondata = function playReceivedAudio(data) {
+
+        // Push received samples onto queue
+        pushAudioPacket(new SampleArray(data));
+
+        // Shift off an arbitrary packet of audio data from the queue (this may
+        // be different in size from the packet just pushed)
+        var packet = shiftAudioPacket();
+        if (!packet)
+            return;
+
+        // Determine exactly when packet CAN play
+        var packetTime = context.currentTime;
+        if (nextPacketTime < packetTime)
+            nextPacketTime = packetTime;
+
         // Set up buffer source
         var source = context.createBufferSource();
         source.connect(context.destination);
@@ -242,11 +452,11 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
             source.start = source.noteOn;
 
         // Schedule packet
-        source.buffer = audioBuffer;
+        source.buffer = toAudioBuffer(packet);
         source.start(nextPacketTime);
 
-        // Update timeline
-        nextPacketTime += duration;
+        // Update timeline by duration of scheduled packet
+        nextPacketTime += packet.length / format.channels / format.rate;
 
     };
 

From d4f4ec0fb297b4c6fc4ec8ea0c8fa810ae255c48 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Fri, 2 Oct 2015 16:52:37 -0700
Subject: [PATCH 8/8] GUAC-1354: Use ArrayBuffer.slice - do not call slice
 directly on typed arrays (not widely supported).

---
 guacamole-common-js/src/main/webapp/modules/AudioPlayer.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
index 98b3189ba..330881caa 100644
--- a/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
+++ b/guacamole-common-js/src/main/webapp/modules/AudioPlayer.js
@@ -332,8 +332,8 @@ Guacamole.RawAudioPlayer = function RawAudioPlayer(stream, mimetype) {
         // Otherwise, split the packet into two new packets according to the
         // calculated optimal split length
         return [
-            data.slice(0, optimalSplitLength),
-            data.slice(optimalSplitLength)
+            new SampleArray(data.buffer.slice(0, optimalSplitLength * format.bytesPerSample)),
+            new SampleArray(data.buffer.slice(optimalSplitLength * format.bytesPerSample))
         ];
 
     };