MediaStreamRecorder.js

// Last time updated: 2016-05-05 6:31:59 AM UTC

// links:
// Open-Sourced: https://github.com/streamproc/MediaStreamRecorder
// https://cdn.WebRTC-Experiment.com/MediaStreamRecorder.js
// https://www.WebRTC-Experiment.com/MediaStreamRecorder.js
// npm install msr

//------------------------------------

// Browsers Support::
// Chrome (all versions) [ audio/video separately ]
// Firefox ( >= 29 ) [ audio/video in single webm/mp4 container or only audio in ogg ]
// Opera (all versions) [ same as chrome ]
// Android (Chrome) [ only video ]
// Android (Opera) [ only video ]
// Android (Firefox) [ only video ]
// Microsoft Edge (Only Audio & Gif)

//------------------------------------
// Muaz Khan     - www.MuazKhan.com
// MIT License   - www.WebRTC-Experiment.com/licence
//------------------------------------

// ______________________
// MediaStreamRecorder.js

function MediaStreamRecorder(mediaStream) {
    if (!mediaStream) {
        throw 'MediaStream is mandatory.';
    }

    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        var Recorder;

        if (typeof MediaRecorder !== 'undefined') {
            Recorder = MediaRecorderWrapper;
        } else if (IsChrome || IsOpera || IsEdge) {
            if (this.mimeType.indexOf('video') !== -1) {
                Recorder = WhammyRecorder;
            } else if (this.mimeType.indexOf('audio') !== -1) {
                Recorder = StereoAudioRecorder;
            }
        }

        // video recorder (in GIF format)
        if (this.mimeType === 'image/gif') {
            Recorder = GifRecorder;
        }

        // audio/wav is supported only via StereoAudioRecorder
        if (this.mimeType === 'audio/wav') {
            Recorder = StereoAudioRecorder;
        }

        // allows forcing StereoAudioRecorder.js on Edge/Firefox
        if (this.recorderType) {
            Recorder = this.recorderType;
        }

        mediaRecorder = new Recorder(mediaStream);
        mediaRecorder.blobs = [];

        var self = this;
        mediaRecorder.ondataavailable = function(data) {
            mediaRecorder.blobs.push(data);
            self.ondataavailable(data);
        };
        mediaRecorder.onstop = this.onstop;
        mediaRecorder.onStartedDrawingNonBlankFrames = this.onStartedDrawingNonBlankFrames;

        // Merge all data-types except "function"
        mediaRecorder = mergeProps(mediaRecorder, this);

        mediaRecorder.start(timeSlice);
    };

    this.onStartedDrawingNonBlankFrames = function() {};
    this.clearOldRecordedFrames = function() {
        if (!mediaRecorder) {
            return;
        }

        mediaRecorder.clearOldRecordedFrames();
    };

    this.stop = function() {
        if (mediaRecorder) {
            mediaRecorder.stop();
        }
    };

    this.ondataavailable = function(blob) {
        console.log('ondataavailable..', blob);
    };

    this.onstop = function(error) {
        console.warn('stopped..', error);
    };

    this.save = function(file, fileName) {
        if (!file) {
            if (!mediaRecorder) {
                return;
            }

            var bigBlob = new Blob(mediaRecorder.blobs, {
                type: mediaRecorder.blobs[0].type || this.mimeType
            });

            invokeSaveAsDialog(bigBlob);
            return;
        }
        invokeSaveAsDialog(file, fileName);
    };

    this.pause = function() {
        if (!mediaRecorder) {
            return;
        }
        mediaRecorder.pause();
        console.log('Paused recording.', this.mimeType || mediaRecorder.mimeType);
    };

    this.resume = function() {
        if (!mediaRecorder) {
            return;
        }
        mediaRecorder.resume();
        console.log('Resumed recording.', this.mimeType || mediaRecorder.mimeType);
    };

    // StereoAudioRecorder || WhammyRecorder || MediaRecorderWrapper || GifRecorder
    this.recorderType = null;

    // video/webm or audio/webm or audio/ogg or audio/wav
    this.mimeType = 'video/webm';

    // logs are enabled by default
    this.disableLogs = false;

    // Reference to "MediaRecorder.js"
    var mediaRecorder;
}

// ______________________
// MultiStreamRecorder.js

function MultiStreamRecorder(mediaStream) {
    if (!mediaStream) {
        throw 'MediaStream is mandatory.';
    }

    var self = this;
    var isMediaRecorder = isMediaRecorderCompatible();

    this.stream = mediaStream;

    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        audioRecorder = new MediaStreamRecorder(mediaStream);
        videoRecorder = new MediaStreamRecorder(mediaStream);

        audioRecorder.mimeType = 'audio/ogg';
        videoRecorder.mimeType = 'video/webm';

        for (var prop in this) {
            if (typeof this[prop] !== 'function') {
                audioRecorder[prop] = videoRecorder[prop] = this[prop];
            }
        }

        audioRecorder.ondataavailable = function(blob) {
            if (!audioVideoBlobs[recordingInterval]) {
                audioVideoBlobs[recordingInterval] = {};
            }

            audioVideoBlobs[recordingInterval].audio = blob;

            if (audioVideoBlobs[recordingInterval].video && !audioVideoBlobs[recordingInterval].onDataAvailableEventFired) {
                audioVideoBlobs[recordingInterval].onDataAvailableEventFired = true;
                fireOnDataAvailableEvent(audioVideoBlobs[recordingInterval]);
            }
        };

        videoRecorder.ondataavailable = function(blob) {
            if (isMediaRecorder) {
                return self.ondataavailable({
                    video: blob,
                    audio: blob
                });
            }

            if (!audioVideoBlobs[recordingInterval]) {
                audioVideoBlobs[recordingInterval] = {};
            }

            audioVideoBlobs[recordingInterval].video = blob;

            if (audioVideoBlobs[recordingInterval].audio && !audioVideoBlobs[recordingInterval].onDataAvailableEventFired) {
                audioVideoBlobs[recordingInterval].onDataAvailableEventFired = true;
                fireOnDataAvailableEvent(audioVideoBlobs[recordingInterval]);
            }
        };

        function fireOnDataAvailableEvent(blobs) {
            recordingInterval++;
            self.ondataavailable(blobs);
        }

        videoRecorder.onstop = audioRecorder.onstop = function(error) {
            self.onstop(error);
        };

        if (!isMediaRecorder) {
            // to make sure both audio/video are synced.
            videoRecorder.onStartedDrawingNonBlankFrames = function() {
                videoRecorder.clearOldRecordedFrames();
                audioRecorder.start(timeSlice);
            };
            videoRecorder.start(timeSlice);
        } else {
            videoRecorder.start(timeSlice);
        }
    };

    this.stop = function() {
        if (audioRecorder) {
            audioRecorder.stop();
        }
        if (videoRecorder) {
            videoRecorder.stop();
        }
    };

    this.ondataavailable = function(blob) {
        console.log('ondataavailable..', blob);
    };

    this.onstop = function(error) {
        console.warn('stopped..', error);
    };

    this.pause = function() {
        if (audioRecorder) {
            audioRecorder.pause();
        }
        if (videoRecorder) {
            videoRecorder.pause();
        }
    };

    this.resume = function() {
        if (audioRecorder) {
            audioRecorder.resume();
        }
        if (videoRecorder) {
            videoRecorder.resume();
        }
    };

    var audioRecorder;
    var videoRecorder;

    var audioVideoBlobs = {};
    var recordingInterval = 0;
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.MultiStreamRecorder = MultiStreamRecorder;
}

// _____________________________
// Cross-Browser-Declarations.js

var browserFakeUserAgent = 'Fake/5.0 (FakeOS) AppleWebKit/123 (KHTML, like Gecko) Fake/12.3.4567.89 Fake/123.45';

(function(that) {
    if (typeof window !== 'undefined') {
        return;
    }

    if (typeof window === 'undefined' && typeof global !== 'undefined') {
        global.navigator = {
            userAgent: browserFakeUserAgent,
            getUserMedia: function() {}
        };

        /*global window:true */
        that.window = global;
    } else if (typeof window === 'undefined') {
        // window = this;
    }

    if (typeof document === 'undefined') {
        /*global document:true */
        that.document = {};

        document.createElement = document.captureStream = document.mozCaptureStream = function() {
            return {};
        };
    }

    if (typeof location === 'undefined') {
        /*global location:true */
        that.location = {
            protocol: 'file:',
            href: '',
            hash: ''
        };
    }

    if (typeof screen === 'undefined') {
        /*global screen:true */
        that.screen = {
            width: 0,
            height: 0
        };
    }
})(typeof global !== 'undefined' ? global : window);

// WebAudio API representer
var AudioContext = window.AudioContext;

if (typeof AudioContext === 'undefined') {
    if (typeof webkitAudioContext !== 'undefined') {
        /*global AudioContext:true */
        AudioContext = webkitAudioContext;
    }

    if (typeof mozAudioContext !== 'undefined') {
        /*global AudioContext:true */
        AudioContext = mozAudioContext;
    }
}

if (typeof window === 'undefined') {
    /*jshint -W020 */
    window = {};
}

// WebAudio API representer
var AudioContext = window.AudioContext;

if (typeof AudioContext === 'undefined') {
    if (typeof webkitAudioContext !== 'undefined') {
        /*global AudioContext:true */
        AudioContext = webkitAudioContext;
    }

    if (typeof mozAudioContext !== 'undefined') {
        /*global AudioContext:true */
        AudioContext = mozAudioContext;
    }
}

/*jshint -W079 */
var URL = window.URL;

if (typeof URL === 'undefined' && typeof webkitURL !== 'undefined') {
    /*global URL:true */
    URL = webkitURL;
}

if (typeof navigator !== 'undefined') {
    if (typeof navigator.webkitGetUserMedia !== 'undefined') {
        navigator.getUserMedia = navigator.webkitGetUserMedia;
    }

    if (typeof navigator.mozGetUserMedia !== 'undefined') {
        navigator.getUserMedia = navigator.mozGetUserMedia;
    }
} else {
    navigator = {
        getUserMedia: function() {},
        userAgent: browserFakeUserAgent
    };
}

var IsEdge = navigator.userAgent.indexOf('Edge') !== -1 && (!!navigator.msSaveBlob || !!navigator.msSaveOrOpenBlob);

var IsOpera = false;
if (typeof opera !== 'undefined' && navigator.userAgent && navigator.userAgent.indexOf('OPR/') !== -1) {
    IsOpera = true;
}
var IsChrome = !IsEdge && !IsEdge && !!navigator.webkitGetUserMedia;

var MediaStream = window.MediaStream;

if (typeof MediaStream === 'undefined' && typeof webkitMediaStream !== 'undefined') {
    MediaStream = webkitMediaStream;
}

/*global MediaStream:true */
if (typeof MediaStream !== 'undefined') {
    if (!('getVideoTracks' in MediaStream.prototype)) {
        MediaStream.prototype.getVideoTracks = function() {
            if (!this.getTracks) {
                return [];
            }

            var tracks = [];
            this.getTracks.forEach(function(track) {
                if (track.kind.toString().indexOf('video') !== -1) {
                    tracks.push(track);
                }
            });
            return tracks;
        };

        MediaStream.prototype.getAudioTracks = function() {
            if (!this.getTracks) {
                return [];
            }

            var tracks = [];
            this.getTracks.forEach(function(track) {
                if (track.kind.toString().indexOf('audio') !== -1) {
                    tracks.push(track);
                }
            });
            return tracks;
        };
    }

    if (!('stop' in MediaStream.prototype)) {
        MediaStream.prototype.stop = function() {
            this.getAudioTracks().forEach(function(track) {
                if (!!track.stop) {
                    track.stop();
                }
            });

            this.getVideoTracks().forEach(function(track) {
                if (!!track.stop) {
                    track.stop();
                }
            });
        };
    }
}

if (typeof location !== 'undefined') {
    if (location.href.indexOf('file:') === 0) {
        console.error('Please load this HTML file on HTTP or HTTPS.');
    }
}

// Merge all other data-types except "function"

function mergeProps(mergein, mergeto) {
    for (var t in mergeto) {
        if (typeof mergeto[t] !== 'function') {
            mergein[t] = mergeto[t];
        }
    }
    return mergein;
}

// "dropFirstFrame" has been added by Graham Roth
// https://github.com/gsroth

function dropFirstFrame(arr) {
    arr.shift();
    return arr;
}

/**
 * @param {Blob} file - File or Blob object. This parameter is required.
 * @param {string} fileName - Optional file name e.g. "Recorded-Video.webm"
 * @example
 * invokeSaveAsDialog(blob or file, [optional] fileName);
 * @see {@link https://github.com/muaz-khan/RecordRTC|RecordRTC Source Code}
 */
function invokeSaveAsDialog(file, fileName) {
    if (!file) {
        throw 'Blob object is required.';
    }

    if (!file.type) {
        try {
            file.type = 'video/webm';
        } catch (e) {}
    }

    var fileExtension = (file.type || 'video/webm').split('/')[1];

    if (fileName && fileName.indexOf('.') !== -1) {
        var splitted = fileName.split('.');
        fileName = splitted[0];
        fileExtension = splitted[1];
    }

    var fileFullName = (fileName || (Math.round(Math.random() * 9999999999) + 888888888)) + '.' + fileExtension;

    if (typeof navigator.msSaveOrOpenBlob !== 'undefined') {
        return navigator.msSaveOrOpenBlob(file, fileFullName);
    } else if (typeof navigator.msSaveBlob !== 'undefined') {
        return navigator.msSaveBlob(file, fileFullName);
    }

    var hyperlink = document.createElement('a');
    hyperlink.href = URL.createObjectURL(file);
    hyperlink.target = '_blank';
    hyperlink.download = fileFullName;

    if (!!navigator.mozGetUserMedia) {
        hyperlink.onclick = function() {
            (document.body || document.documentElement).removeChild(hyperlink);
        };
        (document.body || document.documentElement).appendChild(hyperlink);
    }

    var evt = new MouseEvent('click', {
        view: window,
        bubbles: true,
        cancelable: true
    });

    hyperlink.dispatchEvent(evt);

    if (!navigator.mozGetUserMedia) {
        URL.revokeObjectURL(hyperlink.href);
    }
}

function bytesToSize(bytes) {
    var k = 1000;
    var sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
    if (bytes === 0) {
        return '0 Bytes';
    }
    var i = parseInt(Math.floor(Math.log(bytes) / Math.log(k)), 10);
    return (bytes / Math.pow(k, i)).toPrecision(3) + ' ' + sizes[i];
}

// ______________ (used to handle stuff like http://goo.gl/xmE5eg) issue #129
// ObjectStore.js
var ObjectStore = {
    AudioContext: AudioContext
};

function isMediaRecorderCompatible() {
    var isOpera = !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
    var isChrome = !!window.chrome && !isOpera;
    var isFirefox = typeof window.InstallTrigger !== 'undefined';

    if (isFirefox) {
        return true;
    }

    if (!isChrome) {
        return false;
    }

    var nVer = navigator.appVersion;
    var nAgt = navigator.userAgent;
    var fullVersion = '' + parseFloat(navigator.appVersion);
    var majorVersion = parseInt(navigator.appVersion, 10);
    var nameOffset, verOffset, ix;

    if (isChrome) {
        verOffset = nAgt.indexOf('Chrome');
        fullVersion = nAgt.substring(verOffset + 7);
    }

    // trim the fullVersion string at semicolon/space if present
    if ((ix = fullVersion.indexOf(';')) !== -1) {
        fullVersion = fullVersion.substring(0, ix);
    }

    if ((ix = fullVersion.indexOf(' ')) !== -1) {
        fullVersion = fullVersion.substring(0, ix);
    }

    majorVersion = parseInt('' + fullVersion, 10);

    if (isNaN(majorVersion)) {
        fullVersion = '' + parseFloat(navigator.appVersion);
        majorVersion = parseInt(navigator.appVersion, 10);
    }

    return majorVersion >= 49;
}

// ______________ (used to handle stuff like http://goo.gl/xmE5eg) issue #129
// ObjectStore.js
var ObjectStore = {
    AudioContext: window.AudioContext || window.webkitAudioContext
};

// ==================
// MediaRecorder.js

/**
 * Implementation of https://dvcs.w3.org/hg/dap/raw-file/default/media-stream-capture/MediaRecorder.html
 * The MediaRecorder accepts a mediaStream as input source passed from UA. When recorder starts,
 * a MediaEncoder will be created and accept the mediaStream as input source.
 * Encoder will get the raw data by track data changes, encode it by selected MIME Type, then store the encoded in EncodedBufferCache object.
 * The encoded data will be extracted on every timeslice passed from Start function call or by RequestData function.
 * Thread model:
 * When the recorder starts, it creates a "Media Encoder" thread to read data from MediaEncoder object and store buffer in EncodedBufferCache object.
 * Also extract the encoded data and create blobs on every timeslice passed from start function or RequestData function called by UA.
 */

function MediaRecorderWrapper(mediaStream) {
    var self = this;

    /**
     * This method records MediaStream.
     * @method
     * @memberof MediaStreamRecorder
     * @example
     * recorder.record();
     */
    this.start = function(timeSlice) {
        if (!self.mimeType) {
            self.mimeType = 'video/webm';
        }

        if (self.mimeType.indexOf('audio') !== -1) {
            if (mediaStream.getVideoTracks().length && mediaStream.getAudioTracks().length) {
                var stream;
                if (!!navigator.mozGetUserMedia) {
                    stream = new MediaStream();
                    stream.addTrack(mediaStream.getAudioTracks()[0]);
                } else {
                    // webkitMediaStream
                    stream = new MediaStream(mediaStream.getAudioTracks());
                }
                mediaStream = stream;
            }
        }

        if (self.mimeType.indexOf('audio') !== -1) {
            self.mimeType = IsChrome ? 'audio/webm' : 'audio/ogg';
        }

        self.blob = null;

        var recorderHints = {
            mimeType: self.mimeType
        };

        if (!self.disableLogs) {
            console.log('Passing following params over MediaRecorder API.', recorderHints);
        }

        if (mediaRecorder) {
            // mandatory to make sure Firefox doesn't fails to record streams 3-4 times without reloading the page.
            mediaRecorder = null;
        }

        if (IsChrome && !isMediaRecorderCompatible()) {
            // to support video-only recording on stable
            recorderHints = 'video/vp8';
        }

        // http://dxr.mozilla.org/mozilla-central/source/content/media/MediaRecorder.cpp
        // https://wiki.mozilla.org/Gecko:MediaRecorder
        // https://dvcs.w3.org/hg/dap/raw-file/default/media-stream-capture/MediaRecorder.html

        // starting a recording session; which will initiate "Reading Thread"
        // "Reading Thread" are used to prevent main-thread blocking scenarios
        mediaRecorder = new MediaRecorder(mediaStream, recorderHints);

        if ('canRecordMimeType' in mediaRecorder && mediaRecorder.canRecordMimeType(self.mimeType) === false) {
            if (!self.disableLogs) {
                console.warn('MediaRecorder API seems unable to record mimeType:', self.mimeType);
            }
        }

        // i.e. stop recording when <video> is paused by the user; and auto restart recording 
        // when video is resumed. E.g. yourStream.getVideoTracks()[0].muted = true; // it will auto-stop recording.
        mediaRecorder.ignoreMutedMedia = self.ignoreMutedMedia || false;

        // Dispatching OnDataAvailable Handler
        mediaRecorder.ondataavailable = function(e) {
            if (self.dontFireOnDataAvailableEvent) {
                return;
            }

            if (!e.data || !e.data.size || e.data.size < 100 || self.blob) {
                return;
            }

            var blob = self.getNativeBlob ? e.data : new Blob([e.data], {
                type: self.mimeType || 'video/webm'
            });

            self.ondataavailable(blob);

            // record next interval
            self.start(timeSlice);
        };

        mediaRecorder.onerror = function(error) {
            if (!self.disableLogs) {
                if (error.name === 'InvalidState') {
                    console.error('The MediaRecorder is not in a state in which the proposed operation is allowed to be executed.');
                } else if (error.name === 'OutOfMemory') {
                    console.error('The UA has exhaused the available memory. User agents SHOULD provide as much additional information as possible in the message attribute.');
                } else if (error.name === 'IllegalStreamModification') {
                    console.error('A modification to the stream has occurred that makes it impossible to continue recording. An example would be the addition of a Track while recording is occurring. User agents SHOULD provide as much additional information as possible in the message attribute.');
                } else if (error.name === 'OtherRecordingError') {
                    console.error('Used for an fatal error other than those listed above. User agents SHOULD provide as much additional information as possible in the message attribute.');
                } else if (error.name === 'GenericError') {
                    console.error('The UA cannot provide the codec or recording option that has been requested.', error);
                } else {
                    console.error('MediaRecorder Error', error);
                }
            }

            // When the stream is "ended" set recording to 'inactive' 
            // and stop gathering data. Callers should not rely on 
            // exactness of the timeSlice value, especially 
            // if the timeSlice value is small. Callers should 
            // consider timeSlice as a minimum value

            if (mediaRecorder.state !== 'inactive' && mediaRecorder.state !== 'stopped') {
                mediaRecorder.stop();
            }
        };

        // void start(optional long mTimeSlice)
        // The interval of passing encoded data from EncodedBufferCache to onDataAvailable
        // handler. "mTimeSlice < 0" means Session object does not push encoded data to
        // onDataAvailable, instead, it passive wait the client side pull encoded data
        // by calling requestData API.
        mediaRecorder.start(3.6e+6);

        setTimeout(function() {
            if (!mediaRecorder) {
                return;
            }

            if (mediaRecorder.state === 'recording') {
                // "stop" method auto invokes "requestData"!
                mediaRecorder.requestData();
                mediaRecorder.stop();
            }
        }, timeSlice);

        // Start recording. If timeSlice has been provided, mediaRecorder will
        // raise a dataavailable event containing the Blob of collected data on every timeSlice milliseconds.
        // If timeSlice isn't provided, UA should call the RequestData to obtain the Blob data, also set the mTimeSlice to zero.
    };

    /**
     * This method stops recording MediaStream.
     * @param {function} callback - Callback function, that is used to pass recorded blob back to the callee.
     * @method
     * @memberof MediaStreamRecorder
     * @example
     * recorder.stop(function(blob) {
     *     video.src = URL.createObjectURL(blob);
     * });
     */
    this.stop = function(callback) {
        if (!mediaRecorder) {
            return;
        }

        // mediaRecorder.state === 'recording' means that media recorder is associated with "session"
        // mediaRecorder.state === 'stopped' means that media recorder is detached from the "session" ... in this case; "session" will also be deleted.

        if (mediaRecorder.state === 'recording') {
            // "stop" method auto invokes "requestData"!
            mediaRecorder.requestData();
            mediaRecorder.stop();
        }
    };

    /**
     * This method pauses the recording process.
     * @method
     * @memberof MediaStreamRecorder
     * @example
     * recorder.pause();
     */
    this.pause = function() {
        if (!mediaRecorder) {
            return;
        }

        if (mediaRecorder.state === 'recording') {
            mediaRecorder.pause();
        }
    };

    /**
     * The recorded blobs are passed over this event.
     * @event
     * @memberof MediaStreamRecorder
     * @example
     * recorder.ondataavailable = function(data) {};
     */
    this.ondataavailable = function(blob) {
        console.log('recorded-blob', blob);
    };

    /**
     * This method resumes the recording process.
     * @method
     * @memberof MediaStreamRecorder
     * @example
     * recorder.resume();
     */
    this.resume = function() {
        if (this.dontFireOnDataAvailableEvent) {
            this.dontFireOnDataAvailableEvent = false;

            var disableLogs = self.disableLogs;
            self.disableLogs = true;
            this.record();
            self.disableLogs = disableLogs;
            return;
        }

        if (!mediaRecorder) {
            return;
        }

        if (mediaRecorder.state === 'paused') {
            mediaRecorder.resume();
        }
    };

    /**
     * This method resets currently recorded data.
     * @method
     * @memberof MediaStreamRecorder
     * @example
     * recorder.clearRecordedData();
     */
    this.clearRecordedData = function() {
        if (!mediaRecorder) {
            return;
        }

        this.pause();

        this.dontFireOnDataAvailableEvent = true;
        this.stop();
    };

    // Reference to "MediaRecorder" object
    var mediaRecorder;

    function isMediaStreamActive() {
        if ('active' in mediaStream) {
            if (!mediaStream.active) {
                return false;
            }
        } else if ('ended' in mediaStream) { // old hack
            if (mediaStream.ended) {
                return false;
            }
        }
        return true;
    }

    // this method checks if media stream is stopped
    // or any track is ended.
    (function looper() {
        if (!mediaRecorder) {
            return;
        }

        if (isMediaStreamActive() === false) {
            self.stop();
            return;
        }

        setTimeout(looper, 1000); // check every second
    })();
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.MediaRecorderWrapper = MediaRecorderWrapper;
}

// ======================
// StereoAudioRecorder.js

function StereoAudioRecorder(mediaStream) {
    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        timeSlice = timeSlice || 1000;

        mediaRecorder = new StereoAudioRecorderHelper(mediaStream, this);

        mediaRecorder.record();

        timeout = setInterval(function() {
            mediaRecorder.requestData();
        }, timeSlice);
    };

    this.stop = function() {
        if (mediaRecorder) {
            mediaRecorder.stop();
            clearTimeout(timeout);
        }
    };

    this.pause = function() {
        if (!mediaRecorder) {
            return;
        }

        mediaRecorder.pause();
    };

    this.resume = function() {
        if (!mediaRecorder) {
            return;
        }

        mediaRecorder.resume();
    };

    this.ondataavailable = function() {};

    // Reference to "StereoAudioRecorder" object
    var mediaRecorder;
    var timeout;
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.StereoAudioRecorder = StereoAudioRecorder;
}

// ============================
// StereoAudioRecorderHelper.js

// source code from: http://typedarray.org/wp-content/projects/WebAudioRecorder/script.js

function StereoAudioRecorderHelper(mediaStream, root) {

    // variables    
    var deviceSampleRate = 44100; // range: 22050 to 96000

    if (!ObjectStore.AudioContextConstructor) {
        ObjectStore.AudioContextConstructor = new ObjectStore.AudioContext();
    }

    // check device sample rate
    deviceSampleRate = ObjectStore.AudioContextConstructor.sampleRate;

    var leftchannel = [];
    var rightchannel = [];
    var scriptprocessornode;
    var recording = false;
    var recordingLength = 0;
    var volume;
    var audioInput;
    var sampleRate = root.sampleRate || deviceSampleRate;
    var context;

    var numChannels = root.audioChannels || 2;

    this.record = function() {
        recording = true;
        // reset the buffers for the new recording
        leftchannel.length = rightchannel.length = 0;
        recordingLength = 0;
    };

    this.requestData = function() {
        if (isPaused) {
            return;
        }

        if (recordingLength === 0) {
            requestDataInvoked = false;
            return;
        }

        requestDataInvoked = true;
        // clone stuff
        var internalLeftChannel = leftchannel.slice(0);
        var internalRightChannel = rightchannel.slice(0);
        var internalRecordingLength = recordingLength;

        // reset the buffers for the new recording
        leftchannel.length = rightchannel.length = [];
        recordingLength = 0;
        requestDataInvoked = false;

        // we flat the left and right channels down
        var leftBuffer = mergeBuffers(internalLeftChannel, internalRecordingLength);
        var rightBuffer = mergeBuffers(internalLeftChannel, internalRecordingLength);

        // we interleave both channels together
        if (numChannels === 2) {
            var interleaved = interleave(leftBuffer, rightBuffer);
        } else {
            var interleaved = leftBuffer;
        }

        // we create our wav file
        var buffer = new ArrayBuffer(44 + interleaved.length * 2);
        var view = new DataView(buffer);

        // RIFF chunk descriptor
        writeUTFBytes(view, 0, 'RIFF');
        view.setUint32(4, 44 + interleaved.length * 2, true);
        writeUTFBytes(view, 8, 'WAVE');
        // FMT sub-chunk
        writeUTFBytes(view, 12, 'fmt ');
        view.setUint32(16, 16, true);
        view.setUint16(20, 1, true);
        // stereo (2 channels)
        view.setUint16(22, numChannels, true);
        view.setUint32(24, sampleRate, true);
        view.setUint32(28, sampleRate * 4, true);
        view.setUint16(32, numChannels * 2, true);
        view.setUint16(34, 16, true);
        // data sub-chunk
        writeUTFBytes(view, 36, 'data');
        view.setUint32(40, interleaved.length * 2, true);

        // write the PCM samples
        var lng = interleaved.length;
        var index = 44;
        var volume = 1;
        for (var i = 0; i < lng; i++) {
            view.setInt16(index, interleaved[i] * (0x7FFF * volume), true);
            index += 2;
        }

        // our final binary blob
        var blob = new Blob([view], {
            type: 'audio/wav'
        });

        console.debug('audio recorded blob size:', bytesToSize(blob.size));

        root.ondataavailable(blob);
    };

    this.stop = function() {
        // we stop recording
        recording = false;
        this.requestData();

        audioInput.disconnect();
    };

    function interleave(leftChannel, rightChannel) {
        var length = leftChannel.length + rightChannel.length;
        var result = new Float32Array(length);

        var inputIndex = 0;

        for (var index = 0; index < length;) {
            result[index++] = leftChannel[inputIndex];
            result[index++] = rightChannel[inputIndex];
            inputIndex++;
        }
        return result;
    }

    function mergeBuffers(channelBuffer, recordingLength) {
        var result = new Float32Array(recordingLength);
        var offset = 0;
        var lng = channelBuffer.length;
        for (var i = 0; i < lng; i++) {
            var buffer = channelBuffer[i];
            result.set(buffer, offset);
            offset += buffer.length;
        }
        return result;
    }

    function writeUTFBytes(view, offset, string) {
        var lng = string.length;
        for (var i = 0; i < lng; i++) {
            view.setUint8(offset + i, string.charCodeAt(i));
        }
    }

    // creates the audio context
    var context = ObjectStore.AudioContextConstructor;

    // creates a gain node
    ObjectStore.VolumeGainNode = context.createGain();

    var volume = ObjectStore.VolumeGainNode;

    // creates an audio node from the microphone incoming stream
    ObjectStore.AudioInput = context.createMediaStreamSource(mediaStream);

    // creates an audio node from the microphone incoming stream
    var audioInput = ObjectStore.AudioInput;

    // connect the stream to the gain node
    audioInput.connect(volume);

    /* From the spec: This value controls how frequently the audioprocess event is
    dispatched and how many sample-frames need to be processed each call.
    Lower values for buffer size will result in a lower (better) latency.
    Higher values will be necessary to avoid audio breakup and glitches 
    Legal values are 256, 512, 1024, 2048, 4096, 8192, and 16384.*/
    var bufferSize = root.bufferSize || 2048;
    if (root.bufferSize === 0) {
        bufferSize = 0;
    }

    if (context.createJavaScriptNode) {
        scriptprocessornode = context.createJavaScriptNode(bufferSize, numChannels, numChannels);
    } else if (context.createScriptProcessor) {
        scriptprocessornode = context.createScriptProcessor(bufferSize, numChannels, numChannels);
    } else {
        throw 'WebAudio API has no support on this browser.';
    }

    bufferSize = scriptprocessornode.bufferSize;

    console.debug('using audio buffer-size:', bufferSize);

    var requestDataInvoked = false;

    // sometimes "scriptprocessornode" disconnects from he destination-node
    // and there is no exception thrown in this case.
    // and obviously no further "ondataavailable" events will be emitted.
    // below global-scope variable is added to debug such unexpected but "rare" cases.
    window.scriptprocessornode = scriptprocessornode;

    if (numChannels === 1) {
        console.debug('All right-channels are skipped.');
    }

    var isPaused = false;

    this.pause = function() {
        isPaused = true;
    };

    this.resume = function() {
        isPaused = false;
    };

    // http://webaudio.github.io/web-audio-api/#the-scriptprocessornode-interface
    scriptprocessornode.onaudioprocess = function(e) {
        if (!recording || requestDataInvoked || isPaused) {
            return;
        }

        var left = e.inputBuffer.getChannelData(0);
        leftchannel.push(new Float32Array(left));

        if (numChannels === 2) {
            var right = e.inputBuffer.getChannelData(1);
            rightchannel.push(new Float32Array(right));
        }
        recordingLength += bufferSize;
    };

    volume.connect(scriptprocessornode);
    scriptprocessornode.connect(context.destination);
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.StereoAudioRecorderHelper = StereoAudioRecorderHelper;
}

// ===================
// WhammyRecorder.js

function WhammyRecorder(mediaStream) {
    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        timeSlice = timeSlice || 1000;

        mediaRecorder = new WhammyRecorderHelper(mediaStream, this);

        for (var prop in this) {
            if (typeof this[prop] !== 'function') {
                mediaRecorder[prop] = this[prop];
            }
        }

        mediaRecorder.record();

        timeout = setInterval(function() {
            mediaRecorder.requestData();
        }, timeSlice);
    };

    this.stop = function() {
        if (mediaRecorder) {
            mediaRecorder.stop();
            clearTimeout(timeout);
        }
    };

    this.clearOldRecordedFrames = function() {
        if (mediaRecorder) {
            mediaRecorder.clearOldRecordedFrames();
        }
    };

    this.pause = function() {
        if (!mediaRecorder) {
            return;
        }

        mediaRecorder.pause();
    };

    this.resume = function() {
        if (!mediaRecorder) {
            return;
        }

        mediaRecorder.resume();
    };

    this.ondataavailable = function() {};

    // Reference to "WhammyRecorder" object
    var mediaRecorder;
    var timeout;
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.WhammyRecorder = WhammyRecorder;
}

// ==========================
// WhammyRecorderHelper.js

function WhammyRecorderHelper(mediaStream, root) {
    this.record = function(timeSlice) {
        if (!this.width) {
            this.width = 320;
        }
        if (!this.height) {
            this.height = 240;
        }

        if (this.video && this.video instanceof HTMLVideoElement) {
            if (!this.width) {
                this.width = video.videoWidth || video.clientWidth || 320;
            }
            if (!this.height) {
                this.height = video.videoHeight || video.clientHeight || 240;
            }
        }

        if (!this.video) {
            this.video = {
                width: this.width,
                height: this.height
            };
        }

        if (!this.canvas || !this.canvas.width || !this.canvas.height) {
            this.canvas = {
                width: this.width,
                height: this.height
            };
        }

        canvas.width = this.canvas.width;
        canvas.height = this.canvas.height;

        // setting defaults
        if (this.video && this.video instanceof HTMLVideoElement) {
            this.isHTMLObject = true;
            video = this.video.cloneNode();
        } else {
            video = document.createElement('video');
            video.src = URL.createObjectURL(mediaStream);

            video.width = this.video.width;
            video.height = this.video.height;
        }

        video.muted = true;
        video.play();

        lastTime = new Date().getTime();
        whammy = new Whammy.Video(root.speed, root.quality);

        console.log('canvas resolutions', canvas.width, '*', canvas.height);
        console.log('video width/height', video.width || canvas.width, '*', video.height || canvas.height);

        drawFrames();
    };

    this.clearOldRecordedFrames = function() {
        whammy.frames = [];
    };

    var requestDataInvoked = false;
    this.requestData = function() {
        if (isPaused) {
            return;
        }

        if (!whammy.frames.length) {
            requestDataInvoked = false;
            return;
        }

        requestDataInvoked = true;
        // clone stuff
        var internalFrames = whammy.frames.slice(0);

        // reset the frames for the new recording

        whammy.frames = dropBlackFrames(internalFrames, -1);

        whammy.compile(function(whammyBlob) {
            root.ondataavailable(whammyBlob);
            console.debug('video recorded blob size:', bytesToSize(whammyBlob.size));
        });

        whammy.frames = [];

        requestDataInvoked = false;
    };

    var isOnStartedDrawingNonBlankFramesInvoked = false;

    function drawFrames() {
        if (isPaused) {
            lastTime = new Date().getTime();
            setTimeout(drawFrames, 500);
            return;
        }

        if (isStopDrawing) {
            return;
        }

        if (requestDataInvoked) {
            return setTimeout(drawFrames, 100);
        }

        var duration = new Date().getTime() - lastTime;
        if (!duration) {
            return drawFrames();
        }

        // via webrtc-experiment#206, by Jack i.e. @Seymourr
        lastTime = new Date().getTime();

        if (!self.isHTMLObject && video.paused) {
            video.play(); // Android
        }

        context.drawImage(video, 0, 0, canvas.width, canvas.height);

        if (!isStopDrawing) {
            whammy.frames.push({
                duration: duration,
                image: canvas.toDataURL('image/webp')
            });
        }

        if (!isOnStartedDrawingNonBlankFramesInvoked && !isBlankFrame(whammy.frames[whammy.frames.length - 1])) {
            isOnStartedDrawingNonBlankFramesInvoked = true;
            root.onStartedDrawingNonBlankFrames();
        }

        setTimeout(drawFrames, 10);
    }

    var isStopDrawing = false;

    this.stop = function() {
        isStopDrawing = true;
        this.requestData();
    };

    var canvas = document.createElement('canvas');
    var context = canvas.getContext('2d');

    var video;
    var lastTime;
    var whammy;

    var self = this;

    function isBlankFrame(frame, _pixTolerance, _frameTolerance) {
        var localCanvas = document.createElement('canvas');
        localCanvas.width = canvas.width;
        localCanvas.height = canvas.height;
        var context2d = localCanvas.getContext('2d');

        var sampleColor = {
            r: 0,
            g: 0,
            b: 0
        };
        var maxColorDifference = Math.sqrt(
            Math.pow(255, 2) +
            Math.pow(255, 2) +
            Math.pow(255, 2)
        );
        var pixTolerance = _pixTolerance && _pixTolerance >= 0 && _pixTolerance <= 1 ? _pixTolerance : 0;
        var frameTolerance = _frameTolerance && _frameTolerance >= 0 && _frameTolerance <= 1 ? _frameTolerance : 0;

        var matchPixCount, endPixCheck, maxPixCount;

        var image = new Image();
        image.src = frame.image;
        context2d.drawImage(image, 0, 0, canvas.width, canvas.height);
        var imageData = context2d.getImageData(0, 0, canvas.width, canvas.height);
        matchPixCount = 0;
        endPixCheck = imageData.data.length;
        maxPixCount = imageData.data.length / 4;

        for (var pix = 0; pix < endPixCheck; pix += 4) {
            var currentColor = {
                r: imageData.data[pix],
                g: imageData.data[pix + 1],
                b: imageData.data[pix + 2]
            };
            var colorDifference = Math.sqrt(
                Math.pow(currentColor.r - sampleColor.r, 2) +
                Math.pow(currentColor.g - sampleColor.g, 2) +
                Math.pow(currentColor.b - sampleColor.b, 2)
            );
            // difference in color it is difference in color vectors (r1,g1,b1) <=> (r2,g2,b2)
            if (colorDifference <= maxColorDifference * pixTolerance) {
                matchPixCount++;
            }
        }

        if (maxPixCount - matchPixCount <= maxPixCount * frameTolerance) {
            return false;
        } else {
            return true;
        }
    }

    function dropBlackFrames(_frames, _framesToCheck, _pixTolerance, _frameTolerance) {
        var localCanvas = document.createElement('canvas');
        localCanvas.width = canvas.width;
        localCanvas.height = canvas.height;
        var context2d = localCanvas.getContext('2d');
        var resultFrames = [];

        var checkUntilNotBlack = _framesToCheck === -1;
        var endCheckFrame = (_framesToCheck && _framesToCheck > 0 && _framesToCheck <= _frames.length) ?
            _framesToCheck : _frames.length;
        var sampleColor = {
            r: 0,
            g: 0,
            b: 0
        };
        var maxColorDifference = Math.sqrt(
            Math.pow(255, 2) +
            Math.pow(255, 2) +
            Math.pow(255, 2)
        );
        var pixTolerance = _pixTolerance && _pixTolerance >= 0 && _pixTolerance <= 1 ? _pixTolerance : 0;
        var frameTolerance = _frameTolerance && _frameTolerance >= 0 && _frameTolerance <= 1 ? _frameTolerance : 0;
        var doNotCheckNext = false;

        for (var f = 0; f < endCheckFrame; f++) {
            var matchPixCount, endPixCheck, maxPixCount;

            if (!doNotCheckNext) {
                var image = new Image();
                image.src = _frames[f].image;
                context2d.drawImage(image, 0, 0, canvas.width, canvas.height);
                var imageData = context2d.getImageData(0, 0, canvas.width, canvas.height);
                matchPixCount = 0;
                endPixCheck = imageData.data.length;
                maxPixCount = imageData.data.length / 4;

                for (var pix = 0; pix < endPixCheck; pix += 4) {
                    var currentColor = {
                        r: imageData.data[pix],
                        g: imageData.data[pix + 1],
                        b: imageData.data[pix + 2]
                    };
                    var colorDifference = Math.sqrt(
                        Math.pow(currentColor.r - sampleColor.r, 2) +
                        Math.pow(currentColor.g - sampleColor.g, 2) +
                        Math.pow(currentColor.b - sampleColor.b, 2)
                    );
                    // difference in color it is difference in color vectors (r1,g1,b1) <=> (r2,g2,b2)
                    if (colorDifference <= maxColorDifference * pixTolerance) {
                        matchPixCount++;
                    }
                }
            }

            if (!doNotCheckNext && maxPixCount - matchPixCount <= maxPixCount * frameTolerance) {
                // console.log('removed black frame : ' + f + ' ; frame duration ' + _frames[f].duration);
            } else {
                // console.log('frame is passed : ' + f);
                if (checkUntilNotBlack) {
                    doNotCheckNext = true;
                }
                resultFrames.push(_frames[f]);
            }
        }

        resultFrames = resultFrames.concat(_frames.slice(endCheckFrame));

        if (resultFrames.length <= 0) {
            // at least one last frame should be available for next manipulation
            // if total duration of all frames will be < 1000 than ffmpeg doesn't work well...
            resultFrames.push(_frames[_frames.length - 1]);
        }

        return resultFrames;
    }

    var isPaused = false;

    this.pause = function() {
        isPaused = true;
    };

    this.resume = function() {
        isPaused = false;
    };
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.WhammyRecorderHelper = WhammyRecorderHelper;
}

// --------------
// GifRecorder.js

function GifRecorder(mediaStream) {
    if (typeof GIFEncoder === 'undefined') {
        throw 'Please link: https://cdn.webrtc-experiment.com/gif-recorder.js';
    }

    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        timeSlice = timeSlice || 1000;

        var imageWidth = this.videoWidth || 320;
        var imageHeight = this.videoHeight || 240;

        canvas.width = video.width = imageWidth;
        canvas.height = video.height = imageHeight;

        // external library to record as GIF images
        gifEncoder = new GIFEncoder();

        // void setRepeat(int iter)
        // Sets the number of times the set of GIF frames should be played.
        // Default is 1; 0 means play indefinitely.
        gifEncoder.setRepeat(0);

        // void setFrameRate(Number fps)
        // Sets frame rate in frames per second.
        // Equivalent to setDelay(1000/fps).
        // Using "setDelay" instead of "setFrameRate"
        gifEncoder.setDelay(this.frameRate || this.speed || 200);

        // void setQuality(int quality)
        // Sets quality of color quantization (conversion of images to the
        // maximum 256 colors allowed by the GIF specification).
        // Lower values (minimum = 1) produce better colors,
        // but slow processing significantly. 10 is the default,
        // and produces good color mapping at reasonable speeds.
        // Values greater than 20 do not yield significant improvements in speed.
        gifEncoder.setQuality(this.quality || 1);

        // Boolean start()
        // This writes the GIF Header and returns false if it fails.
        gifEncoder.start();

        startTime = Date.now();

        function drawVideoFrame(time) {
            if (isPaused) {
                setTimeout(drawVideoFrame, 500, time);
                return;
            }

            lastAnimationFrame = requestAnimationFrame(drawVideoFrame);

            if (typeof lastFrameTime === undefined) {
                lastFrameTime = time;
            }

            // ~10 fps
            if (time - lastFrameTime < 90) {
                return;
            }

            if (video.paused) {
                video.play(); // Android
            }

            context.drawImage(video, 0, 0, imageWidth, imageHeight);

            gifEncoder.addFrame(context);

            // console.log('Recording...' + Math.round((Date.now() - startTime) / 1000) + 's');
            // console.log("fps: ", 1000 / (time - lastFrameTime));

            lastFrameTime = time;
        }

        lastAnimationFrame = requestAnimationFrame(drawVideoFrame);

        timeout = setTimeout(doneRecording, timeSlice);
    };

    function doneRecording() {
        endTime = Date.now();

        var gifBlob = new Blob([new Uint8Array(gifEncoder.stream().bin)], {
            type: 'image/gif'
        });
        self.ondataavailable(gifBlob);

        // todo: find a way to clear old recorded blobs
        gifEncoder.stream().bin = [];
    }

    this.stop = function() {
        if (lastAnimationFrame) {
            cancelAnimationFrame(lastAnimationFrame);
            clearTimeout(timeout);
            doneRecording();
        }
    };

    var isPaused = false;

    this.pause = function() {
        isPaused = true;
    };

    this.resume = function() {
        isPaused = false;
    };

    this.ondataavailable = function() {};
    this.onstop = function() {};

    // Reference to itself
    var self = this;

    var canvas = document.createElement('canvas');
    var context = canvas.getContext('2d');

    var video = document.createElement('video');
    video.muted = true;
    video.autoplay = true;
    video.src = URL.createObjectURL(mediaStream);
    video.play();

    var lastAnimationFrame = null;
    var startTime, endTime, lastFrameTime;

    var gifEncoder;
    var timeout;
}

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.GifRecorder = GifRecorder;
}

// https://github.com/antimatter15/whammy/blob/master/LICENSE
// _________
// Whammy.js

// todo: Firefox now supports webp for webm containers!
// their MediaRecorder implementation works well!
// should we provide an option to record via Whammy.js or MediaRecorder API is a better solution?

/**
 * Whammy is a standalone class used by {@link RecordRTC} to bring video recording in Chrome. It is written by {@link https://github.com/antimatter15|antimatter15}
 * @summary A real time javascript webm encoder based on a canvas hack.
 * @typedef Whammy
 * @class
 * @example
 * var recorder = new Whammy().Video(15);
 * recorder.add(context || canvas || dataURL);
 * var output = recorder.compile();
 */

var Whammy = (function() {
    // a more abstract-ish API

    function WhammyVideo(duration, quality) {
        this.frames = [];
        if (!duration) {
            duration = 1;
        }
        this.duration = 1000 / duration;
        this.quality = quality || 0.8;
    }

    /**
     * Pass Canvas or Context or image/webp(string) to {@link Whammy} encoder.
     * @method
     * @memberof Whammy
     * @example
     * recorder = new Whammy().Video(0.8, 100);
     * recorder.add(canvas || context || 'image/webp');
     * @param {string} frame - Canvas || Context || image/webp
     * @param {number} duration - Stick a duration (in milliseconds)
     */
    WhammyVideo.prototype.add = function(frame, duration) {
        if ('canvas' in frame) { //CanvasRenderingContext2D
            frame = frame.canvas;
        }

        if ('toDataURL' in frame) {
            frame = frame.toDataURL('image/webp', this.quality);
        }

        if (!(/^data:image\/webp;base64,/ig).test(frame)) {
            throw 'Input must be formatted properly as a base64 encoded DataURI of type image/webp';
        }
        this.frames.push({
            image: frame,
            duration: duration || this.duration
        });
    };

    function processInWebWorker(_function) {
        var blob = URL.createObjectURL(new Blob([_function.toString(),
            'this.onmessage =  function (e) {' + _function.name + '(e.data);}'
        ], {
            type: 'application/javascript'
        }));

        var worker = new Worker(blob);
        URL.revokeObjectURL(blob);
        return worker;
    }

    function whammyInWebWorker(frames) {
        function ArrayToWebM(frames) {
            var info = checkFrames(frames);
            if (!info) {
                return [];
            }

            var clusterMaxDuration = 30000;

            var EBML = [{
                'id': 0x1a45dfa3, // EBML
                'data': [{
                    'data': 1,
                    'id': 0x4286 // EBMLVersion
                }, {
                    'data': 1,
                    'id': 0x42f7 // EBMLReadVersion
                }, {
                    'data': 4,
                    'id': 0x42f2 // EBMLMaxIDLength
                }, {
                    'data': 8,
                    'id': 0x42f3 // EBMLMaxSizeLength
                }, {
                    'data': 'webm',
                    'id': 0x4282 // DocType
                }, {
                    'data': 2,
                    'id': 0x4287 // DocTypeVersion
                }, {
                    'data': 2,
                    'id': 0x4285 // DocTypeReadVersion
                }]
            }, {
                'id': 0x18538067, // Segment
                'data': [{
                    'id': 0x1549a966, // Info
                    'data': [{
                        'data': 1e6, //do things in millisecs (num of nanosecs for duration scale)
                        'id': 0x2ad7b1 // TimecodeScale
                    }, {
                        'data': 'whammy',
                        'id': 0x4d80 // MuxingApp
                    }, {
                        'data': 'whammy',
                        'id': 0x5741 // WritingApp
                    }, {
                        'data': doubleToString(info.duration),
                        'id': 0x4489 // Duration
                    }]
                }, {
                    'id': 0x1654ae6b, // Tracks
                    'data': [{
                        'id': 0xae, // TrackEntry
                        'data': [{
                            'data': 1,
                            'id': 0xd7 // TrackNumber
                        }, {
                            'data': 1,
                            'id': 0x73c5 // TrackUID
                        }, {
                            'data': 0,
                            'id': 0x9c // FlagLacing
                        }, {
                            'data': 'und',
                            'id': 0x22b59c // Language
                        }, {
                            'data': 'V_VP8',
                            'id': 0x86 // CodecID
                        }, {
                            'data': 'VP8',
                            'id': 0x258688 // CodecName
                        }, {
                            'data': 1,
                            'id': 0x83 // TrackType
                        }, {
                            'id': 0xe0, // Video
                            'data': [{
                                'data': info.width,
                                'id': 0xb0 // PixelWidth
                            }, {
                                'data': info.height,
                                'id': 0xba // PixelHeight
                            }]
                        }]
                    }]
                }]
            }];

            //Generate clusters (max duration)
            var frameNumber = 0;
            var clusterTimecode = 0;
            while (frameNumber < frames.length) {

                var clusterFrames = [];
                var clusterDuration = 0;
                do {
                    clusterFrames.push(frames[frameNumber]);
                    clusterDuration += frames[frameNumber].duration;
                    frameNumber++;
                } while (frameNumber < frames.length && clusterDuration < clusterMaxDuration);

                var clusterCounter = 0;
                var cluster = {
                    'id': 0x1f43b675, // Cluster
                    'data': getClusterData(clusterTimecode, clusterCounter, clusterFrames)
                }; //Add cluster to segment
                EBML[1].data.push(cluster);
                clusterTimecode += clusterDuration;
            }

            return generateEBML(EBML);
        }

        function getClusterData(clusterTimecode, clusterCounter, clusterFrames) {
            return [{
                'data': clusterTimecode,
                'id': 0xe7 // Timecode
            }].concat(clusterFrames.map(function(webp) {
                var block = makeSimpleBlock({
                    discardable: 0,
                    frame: webp.data.slice(4),
                    invisible: 0,
                    keyframe: 1,
                    lacing: 0,
                    trackNum: 1,
                    timecode: Math.round(clusterCounter)
                });
                clusterCounter += webp.duration;
                return {
                    data: block,
                    id: 0xa3
                };
            }));
        }

        // sums the lengths of all the frames and gets the duration

        function checkFrames(frames) {
            if (!frames[0]) {
                postMessage({
                    error: 'Something went wrong. Maybe WebP format is not supported in the current browser.'
                });
                return;
            }

            var width = frames[0].width,
                height = frames[0].height,
                duration = frames[0].duration;

            for (var i = 1; i < frames.length; i++) {
                duration += frames[i].duration;
            }
            return {
                duration: duration,
                width: width,
                height: height
            };
        }

        function numToBuffer(num) {
            var parts = [];
            while (num > 0) {
                parts.push(num & 0xff);
                num = num >> 8;
            }
            return new Uint8Array(parts.reverse());
        }

        function strToBuffer(str) {
            return new Uint8Array(str.split('').map(function(e) {
                return e.charCodeAt(0);
            }));
        }

        function bitsToBuffer(bits) {
            var data = [];
            var pad = (bits.length % 8) ? (new Array(1 + 8 - (bits.length % 8))).join('0') : '';
            bits = pad + bits;
            for (var i = 0; i < bits.length; i += 8) {
                data.push(parseInt(bits.substr(i, 8), 2));
            }
            return new Uint8Array(data);
        }

        function generateEBML(json) {
            var ebml = [];
            for (var i = 0; i < json.length; i++) {
                var data = json[i].data;

                if (typeof data === 'object') {
                    data = generateEBML(data);
                }

                if (typeof data === 'number') {
                    data = bitsToBuffer(data.toString(2));
                }

                if (typeof data === 'string') {
                    data = strToBuffer(data);
                }

                var len = data.size || data.byteLength || data.length;
                var zeroes = Math.ceil(Math.ceil(Math.log(len) / Math.log(2)) / 8);
                var sizeToString = len.toString(2);
                var padded = (new Array((zeroes * 7 + 7 + 1) - sizeToString.length)).join('0') + sizeToString;
                var size = (new Array(zeroes)).join('0') + '1' + padded;

                ebml.push(numToBuffer(json[i].id));
                ebml.push(bitsToBuffer(size));
                ebml.push(data);
            }

            return new Blob(ebml, {
                type: 'video/webm'
            });
        }

        function toBinStrOld(bits) {
            var data = '';
            var pad = (bits.length % 8) ? (new Array(1 + 8 - (bits.length % 8))).join('0') : '';
            bits = pad + bits;
            for (var i = 0; i < bits.length; i += 8) {
                data += String.fromCharCode(parseInt(bits.substr(i, 8), 2));
            }
            return data;
        }

        function makeSimpleBlock(data) {
            var flags = 0;

            if (data.keyframe) {
                flags |= 128;
            }

            if (data.invisible) {
                flags |= 8;
            }

            if (data.lacing) {
                flags |= (data.lacing << 1);
            }

            if (data.discardable) {
                flags |= 1;
            }

            if (data.trackNum > 127) {
                throw 'TrackNumber > 127 not supported';
            }

            var out = [data.trackNum | 0x80, data.timecode >> 8, data.timecode & 0xff, flags].map(function(e) {
                return String.fromCharCode(e);
            }).join('') + data.frame;

            return out;
        }

        function parseWebP(riff) {
            var VP8 = riff.RIFF[0].WEBP[0];

            var frameStart = VP8.indexOf('\x9d\x01\x2a'); // A VP8 keyframe starts with the 0x9d012a header
            for (var i = 0, c = []; i < 4; i++) {
                c[i] = VP8.charCodeAt(frameStart + 3 + i);
            }

            var width, height, tmp;

            //the code below is literally copied verbatim from the bitstream spec
            tmp = (c[1] << 8) | c[0];
            width = tmp & 0x3FFF;
            tmp = (c[3] << 8) | c[2];
            height = tmp & 0x3FFF;
            return {
                width: width,
                height: height,
                data: VP8,
                riff: riff
            };
        }

        function getStrLength(string, offset) {
            return parseInt(string.substr(offset + 4, 4).split('').map(function(i) {
                var unpadded = i.charCodeAt(0).toString(2);
                return (new Array(8 - unpadded.length + 1)).join('0') + unpadded;
            }).join(''), 2);
        }

        function parseRIFF(string) {
            var offset = 0;
            var chunks = {};

            while (offset < string.length) {
                var id = string.substr(offset, 4);
                var len = getStrLength(string, offset);
                var data = string.substr(offset + 4 + 4, len);
                offset += 4 + 4 + len;
                chunks[id] = chunks[id] || [];

                if (id === 'RIFF' || id === 'LIST') {
                    chunks[id].push(parseRIFF(data));
                } else {
                    chunks[id].push(data);
                }
            }
            return chunks;
        }

        function doubleToString(num) {
            return [].slice.call(
                new Uint8Array((new Float64Array([num])).buffer), 0).map(function(e) {
                return String.fromCharCode(e);
            }).reverse().join('');
        }

        var webm = new ArrayToWebM(frames.map(function(frame) {
            var webp = parseWebP(parseRIFF(atob(frame.image.slice(23))));
            webp.duration = frame.duration;
            return webp;
        }));

        postMessage(webm);
    }

    /**
     * Encodes frames in WebM container. It uses WebWorkinvoke to invoke 'ArrayToWebM' method.
     * @param {function} callback - Callback function, that is used to pass recorded blob back to the callee.
     * @method
     * @memberof Whammy
     * @example
     * recorder = new Whammy().Video(0.8, 100);
     * recorder.compile(function(blob) {
     *    // blob.size - blob.type
     * });
     */
    WhammyVideo.prototype.compile = function(callback) {
        var webWorker = processInWebWorker(whammyInWebWorker);

        webWorker.onmessage = function(event) {
            if (event.data.error) {
                console.error(event.data.error);
                return;
            }
            callback(event.data);
        };

        webWorker.postMessage(this.frames);
    };

    return {
        /**
         * A more abstract-ish API.
         * @method
         * @memberof Whammy
         * @example
         * recorder = new Whammy().Video(0.8, 100);
         * @param {?number} speed - 0.8
         * @param {?number} quality - 100
         */
        Video: WhammyVideo
    };
})();

if (typeof MediaStreamRecorder !== 'undefined') {
    MediaStreamRecorder.Whammy = Whammy;
}

// https://github.com/streamproc/MediaStreamRecorder/issues/42
if (typeof module !== 'undefined' /* && !!module.exports*/ ) {
    module.exports = MediaStreamRecorder;
}

if (typeof define === 'function' && define.amd) {
    define('MediaStreamRecorder', [], function() {
        return MediaStreamRecorder;
    });
}