GUAC-1511: Implement Guacamole.AudioRecorder and Guacamole.RawAudioRecorder.

guacamole-common-js/src/main/webapp/modules/AudioRecorder.js

@@ -0,0 +1,324 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+var Guacamole = Guacamole || {};
+
+/**
+ * Abstract audio recorder which streams arbitrary audio data to an underlying
+ * Guacamole.OutputStream. It is up to implementations of this class to provide
+ * some means of handling this Guacamole.OutputStream. Data produced by the
+ * recorder is to be sent along the provided stream immediately.
+ *
+ * @constructor
+ */
+Guacamole.AudioRecorder = function AudioRecorder() {
+
+    // AudioRecorder currently provides no functions
+
+};
+
+/**
+ * Determines whether the given mimetype is supported by any built-in
+ * implementation of Guacamole.AudioRecorder, and thus will be properly handled
+ * by Guacamole.AudioRecorder.getInstance().
+ *
+ * @param {String} mimetype
+ *     The mimetype to check.
+ *
+ * @returns {Boolean}
+ *     true if the given mimetype is supported by any built-in
+ *     Guacamole.AudioRecorder, false otherwise.
+ */
+Guacamole.AudioRecorder.isSupportedType = function isSupportedType(mimetype) {
+
+    return Guacamole.RawAudioRecorder.isSupportedType(mimetype);
+
+};
+
+/**
+ * Returns a list of all mimetypes supported by any built-in
+ * Guacamole.AudioRecorder, 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.AudioRecorder, excluding any parameters.
+ */
+Guacamole.AudioRecorder.getSupportedTypes = function getSupportedTypes() {
+
+    return Guacamole.RawAudioRecorder.getSupportedTypes();
+
+};
+
+/**
+ * Returns an instance of Guacamole.AudioRecorder providing support for the
+ * given audio format. If support for the given audio format is not available,
+ * null is returned.
+ *
+ * @param {Guacamole.OutputStream} stream
+ *     The Guacamole.OutputStream to send audio data through.
+ *
+ * @param {String} mimetype
+ *     The mimetype of the audio data to be sent along the provided stream.
+ *
+ * @return {Guacamole.AudioRecorder}
+ *     A Guacamole.AudioRecorder instance supporting the given mimetype and
+ *     writing to the given stream, or null if support for the given mimetype
+ *     is absent.
+ */
+Guacamole.AudioRecorder.getInstance = function getInstance(stream, mimetype) {
+
+    // Use raw audio recorder if possible
+    if (Guacamole.RawAudioRecorder.isSupportedType(mimetype))
+        return new Guacamole.RawAudioRecorder(stream, mimetype);
+
+    // No support for given mimetype
+    return null;
+
+};
+
+/**
+ * Implementation of Guacamole.AudioRecorder providing support for raw PCM
+ * format audio. This recorder relies only on the Web Audio API and does not
+ * require any browser-level support for its audio formats.
+ *
+ * @constructor
+ * @augments Guacamole.AudioRecorder
+ * @param {Guacamole.OutputStream} stream
+ *     The Guacamole.OutputStream to write audio data to.
+ *
+ * @param {String} mimetype
+ *     The mimetype of the audio data to send along 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.RawAudioRecorder = function RawAudioRecorder(stream, mimetype) {
+
+    /**
+     * The format of audio this recorder will encode.
+     *
+     * @private
+     * @type {Guacamole.RawAudioFormat}
+     */
+    var format = Guacamole.RawAudioFormat.parse(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() {
+
+        // 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;
+
+    })();
+
+    /**
+     * A function which directly invokes the browser's implementation of
+     * navigator.getUserMedia() with all provided parameters.
+     *
+     * @type Function
+     */
+    var getUserMedia = (navigator.getUserMedia
+            || navigator.webkitGetUserMedia
+            || navigator.mozGetUserMedia
+            || navigator.msGetUserMedia).bind(navigator);
+
+    /**
+     * Guacamole.ArrayBufferWriter wrapped around the audio output stream
+     * provided when this Guacamole.RawAudioRecorder was created.
+     *
+     * @private
+     * @type {Guacamole.ArrayBufferWriter}
+     */
+    var writer = new Guacamole.ArrayBufferWriter(stream);
+
+    /**
+     * 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 sent
+     * by this audio recorder. 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 size of audio buffer to request from the Web Audio API when
+     * recording audio. This must be a power of two between 256 and 16384
+     * inclusive, as required by AudioContext.createScriptProcessor().
+     *
+     * @private
+     * @type {Number}
+     */
+    var bufferSize = format.bytesPerSample * 4096;
+
+    /**
+     * Converts the given AudioBuffer into an audio packet, ready for streaming
+     * along the underlying output stream. Unlike the raw audio packets used by
+     * this audio recorder, AudioBuffers require floating point samples and are
+     * split into isolated planes of channel-specific data.
+     *
+     * @private
+     * @param {AudioBuffer} audioBuffer
+     *     The Web Audio API AudioBuffer that should be converted to a raw
+     *     audio packet.
+     *
+     * @returns {SampleArray}
+     *     A new raw audio packet containing the audio data from the provided
+     *     AudioBuffer.
+     */
+    var toSampleArray = function toSampleArray(audioBuffer) {
+
+        // Get array for raw PCM storage
+        var data = new SampleArray(audioBuffer.length);
+
+        // Convert each channel
+        for (var channel = 0; channel < format.channels; channel++) {
+
+            var audioData = audioBuffer.getChannelData(channel);
+
+            // Fill array with data from audio buffer channel
+            var offset = channel;
+            for (var i = 0; i < audioData.length; i++) {
+                data[offset] = audioData[i] * maxSampleValue;
+                offset += format.channels;
+            }
+
+        }
+
+        return data;
+
+    };
+
+    // Once audio stream is successfully open, request and begin reading audio
+    writer.onack = function audioStreamAcknowledged(status) {
+
+        // Abort stream if rejected
+        if (status.code !== Guacamole.Status.Code.SUCCESS) {
+            writer.sendEnd();
+            return;
+        }
+
+        // Attempt to retrieve an audio input stream from the browser
+        getUserMedia({ 'audio' : true }, function streamReceived(mediaStream) {
+
+            // Create processing node which receives appropriately-sized audio buffers
+            var processor = context.createScriptProcessor(bufferSize, format.channels, format.channels);
+            processor.connect(context.destination);
+
+            // Send blobs when audio buffers are received
+            processor.onaudioprocess = function processAudio(e) {
+                writer.sendData(toSampleArray(e.inputBuffer));
+            };
+
+            // Connect processing node to user's audio input source
+            var source = context.createMediaStreamSource(mediaStream);
+            source.connect(processor);
+
+        }, function streamDenied() {
+
+            // Simply end stream if audio access is not allowed
+            writer.sendEnd();
+
+        });
+
+    };
+
+};
+
+Guacamole.RawAudioRecorder.prototype = new Guacamole.AudioRecorder();
+
+/**
+ * Determines whether the given mimetype is supported by
+ * Guacamole.RawAudioRecorder.
+ *
+ * @param {String} mimetype
+ *     The mimetype to check.
+ *
+ * @returns {Boolean}
+ *     true if the given mimetype is supported by Guacamole.RawAudioRecorder,
+ *     false otherwise.
+ */
+Guacamole.RawAudioRecorder.isSupportedType = function isSupportedType(mimetype) {
+
+    // No supported types if no Web Audio API
+    if (!window.AudioContext && !window.webkitAudioContext)
+        return false;
+
+    return Guacamole.RawAudioFormat.parse(mimetype) !== null;
+
+};
+
+/**
+ * Returns a list of all mimetypes supported by Guacamole.RawAudioRecorder. 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.RawAudioRecorder,
+ *     excluding any parameters. If the necessary JavaScript APIs for recording
+ *     raw audio are absent, this list will be empty.
+ */
+Guacamole.RawAudioRecorder.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'
+    ];
+
+};