/*
var vid = new Whammy.Video();
vid.add(canvas or data url)
vid.compile()
*/
var Whammy = (function(){
// in this case, frames has a very specific meaning, which will be
// detailed once i finish writing the code
function toWebM(frames, outputAsArray){
var info = checkFrames(frames);
//max duration by cluster in milliseconds
var CLUSTER_MAX_DURATION = 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": 0x63c5 // 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
}
]
}
]
}
]
},
//cluster insertion point
]
}
];
//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 < CLUSTER_MAX_DURATION);
var clusterCounter = 0;
var cluster = {
"id": 0x1f43b675, // Cluster
"data": [
{
"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
};
}))
}
//Add cluster to segment
EBML[1].data.push(cluster);
clusterTimecode += clusterDuration;
}
return generateEBML(EBML, outputAsArray)
}
// sums the lengths of all the frames and gets the duration, woo
function checkFrames(frames){
var width = frames[0].width,
height = frames[0].height,
duration = frames[0].duration;
for(var i = 1; i < frames.length; i++){
if(frames[i].width != width) throw "Frame " + (i + 1) + " has a different width";
if(frames[i].height != height) throw "Frame " + (i + 1) + " has a different height";
if(frames[i].duration < 0 || frames[i].duration > 0x7fff) throw "Frame " + (i + 1) + " has a weird duration (must be between 0 and 32767)";
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 Blob([str]);
var arr = new Uint8Array(str.length);
for(var i = 0; i < str.length; i++){
arr[i] = str.charCodeAt(i)
}
return arr;
// this is slower
// return new Uint8Array(str.split('').map(function(e){
// return e.charCodeAt(0)
// }))
}
//sorry this is ugly, and sort of hard to understand exactly why this was done
// at all really, but the reason is that there's some code below that i dont really
// feel like understanding, and this is easier than using my brain.
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, outputAsArray){
var ebml = [];
for(var i = 0; i < json.length; i++){
var data = json[i].data;
if(typeof data == 'object') data = generateEBML(data, outputAsArray);
if(typeof data == 'number') data = bitsToBuffer(data.toString(2));
if(typeof data == 'string') data = strToBuffer(data);
if(data.length){
var z = z;
}
var len = data.size || data.byteLength || data.length;
var zeroes = Math.ceil(Math.ceil(Math.log(len)/Math.log(2))/8);
var size_str = len.toString(2);
var padded = (new Array((zeroes * 7 + 7 + 1) - size_str.length)).join('0') + size_str;
var size = (new Array(zeroes)).join('0') + '1' + padded;
//i actually dont quite understand what went on up there, so I'm not really
//going to fix this, i'm probably just going to write some hacky thing which
//converts that string into a buffer-esque thing
ebml.push(numToBuffer(json[i].id));
ebml.push(bitsToBuffer(size));
ebml.push(data)
}
//output as blob or byteArray
if(outputAsArray){
//convert ebml to an array
var buffer = toFlatArray(ebml)
return new Uint8Array(buffer);
}else{
return new Blob(ebml, {type: "video/webm"});
}
}
function toFlatArray(arr, outBuffer){
if(outBuffer == null){
outBuffer = [];
}
for(var i = 0; i < arr.length; i++){
if(typeof arr[i] == 'object'){
//an array
toFlatArray(arr[i], outBuffer)
}else{
//a simple element
outBuffer.push(arr[i]);
}
}
return outBuffer;
}
//woot, a function that's actually written for this project!
//this parses some json markup and makes it into that binary magic
//which can then get shoved into the matroska comtainer (peaceably)
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;
}
// here's something else taken verbatim from weppy, awesome rite?
function parseWebP(riff){
var VP8 = riff.RIFF[0].WEBP[0];
var frame_start = 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(frame_start + 3 + i);
var width, horizontal_scale, height, vertical_scale, tmp;
//the code below is literally copied verbatim from the bitstream spec
tmp = (c[1] << 8) | c[0];
width = tmp & 0x3FFF;
horizontal_scale = tmp >> 14;
tmp = (c[3] << 8) | c[2];
height = tmp & 0x3FFF;
vertical_scale = tmp >> 14;
return {
width: width,
height: height,
data: VP8,
riff: riff
}
}
// i think i'm going off on a riff by pretending this is some known
// idiom which i'm making a casual and brilliant pun about, but since
// i can't find anything on google which conforms to this idiomatic
// usage, I'm assuming this is just a consequence of some psychotic
// break which makes me make up puns. well, enough riff-raff (aha a
// rescue of sorts), this function was ripped wholesale from weppy
function parseRIFF(string){
var offset = 0;
var chunks = {};
while (offset < string.length) {
var id = string.substr(offset, 4);
var len = 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);
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;
}
// here's a little utility function that acts as a utility for other functions
// basically, the only purpose is for encoding "Duration", which is encoded as
// a double (considerably more difficult to encode than an integer)
function doubleToString(num){
return [].slice.call(
new Uint8Array(
(
new Float64Array([num]) //create a float64 array
).buffer) //extract the array buffer
, 0) // convert the Uint8Array into a regular array
.map(function(e){ //since it's a regular array, we can now use map
return String.fromCharCode(e) // encode all the bytes individually
})
.reverse() //correct the byte endianness (assume it's little endian for now)
.join('') // join the bytes in holy matrimony as a string
}
function WhammyVideo(speed, quality){ // a more abstract-ish API
this.frames = [];
this.duration = 1000 / speed;
this.quality = quality || 0.8;
}
WhammyVideo.prototype.add = function(frame, duration){
if(typeof duration != 'undefined' && this.duration) throw "you can't pass a duration if the fps is set";
if(typeof duration == 'undefined' && !this.duration) throw "if you don't have the fps set, you ned to have durations here."
if('canvas' in frame){ //CanvasRenderingContext2D
frame = frame.canvas;
}
if('toDataURL' in frame){
frame = frame.toDataURL('image/webp', this.quality)
}else if(typeof frame != "string"){
throw "frame must be a a HTMLCanvasElement, a CanvasRenderingContext2D or a DataURI formatted string"
}
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
})
}
WhammyVideo.prototype.compile = function(outputAsArray){
return new toWebM(this.frames.map(function(frame){
var webp = parseWebP(parseRIFF(atob(frame.image.slice(23))));
webp.duration = frame.duration;
return webp;
}), outputAsArray)
}
return {
Video: WhammyVideo,
fromImageArray: function(images, fps, outputAsArray){
return toWebM(images.map(function(image){
var webp = parseWebP(parseRIFF(atob(image.slice(23))))
webp.duration = 1000 / fps;
return webp;
}), outputAsArray)
},
toWebM: toWebM
// expose methods of madness
}
})()
window.URL = window.URL || window.webkitURL;
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia ||
navigator.mozGetUserMedia || navigator.msGetUserMedia;
window.requestAnimationFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame
})();
var video;
var width;
var height;
var canvas;
var images = [];
var ctx;
var result;
var capture;
var loopnum;
var startTime;
var capturing = false;
var msgdiv;
var progress;
var startButton;
var stopButton;
window.onload = function() {
init();
var onFailSoHard = function(e) {
console.log('Rejected!', e);
};
if (navigator.getUserMedia) {
navigator.getUserMedia({
audio : false,
video : true
}, function(stream) {
video.src = window.URL.createObjectURL(stream);
}, onFailSoHard);
} else {
}
};
/**
* Set the HTML elements we need.
*/
function init() {
video = document.getElementById('campreview');
canvas = document.createElement('canvas');
ctx = canvas.getContext('2d');
result = document.getElementById('result');
msgdiv = document.getElementById('information');
progress = document.getElementById('progress');
startButton = document.getElementById('startButton');
stopButton = document.getElementById('stopButton');
}
/**
* Capture the next frame of the video.
*/
function nextFrame(){
if(capturing){
var imageData;
ctx.drawImage(video, 0, 0, width, height);
imageData = ctx.getImageData(0, 0, width, height);
images.push({duration : new Date().getTime() - startTime, datas : imageData});
startTime = new Date().getTime();
requestAnimationFrame(nextFrame);
}else{
requestAnimationFrame(finalizeVideo);
}
}
/**
* Start the encoding of the captured frames.
*/
function finalizeVideo(){
var capture = new Whammy.Video();
setMessage('Encoding video...');
progress.max = images.length;
showProgress(true);
encodeVideo(capture, 0);
}
/**
* Encode the captured frames.
*
* @param capture
* @param currentImage
*/
function encodeVideo(capture, currentImage) {
if (currentImage < images.length) {
ctx.putImageData(images[currentImage].datas, 0, 0);
capture.add(ctx, images[currentImage].duration);
delete images[currentImage];
progress.value = currentImage;
currentImage++;
setTimeout(function() {encodeVideo(capture, currentImage);}, 5);
} else {
var output = capture.compile();
result.src = window.URL.createObjectURL(output);
setMessage('Finished');
images = [];
enableStartButton(true);
}
}
/**
* Initialize the canvas' size with the video's size.
*/
function initSize() {
width = video.clientWidth;
height = video.clientHeight;
canvas.width = width;
canvas.height = height;
}
/**
* Initialize the css style of the buttons and the progress bar
* when capturing.
*/
function initStyle() {
setMessage('Capturing...');
showProgress(false);
enableStartButton(false);
enableStopButton(true);
}
/**
* Start the video capture.
*/
function startCapture() {
initSize();
initStyle();
capturing = true;
startTime = new Date().getTime();
nextFrame();
}
/**
* Stop the video capture.
*/
function stopCapture() {
capturing = false;
enableStopButton(false);
}
/* *************************************************************
* Styles functions
* *************************************************************/
/**
* Enable/Disable the start button.
*/
function enableStartButton(enabled) {
startButton.disabled = !enabled;
}
/**
* Enable/Disable the stop button.
*/
function enableStopButton(enabled) {
stopButton.disabled = !enabled;
}
/**
* Display/Hide the progress bar.
*/
function showProgress(show) {
progress.style.visibility = show ? 'visible' : 'hidden';
}
/**
* Display a message in the msgdiv block.
*/
function setMessage(message) {
msgdiv.innerHTML = message;
}