Groover = (function(){ // ensure webp is supported function canEncode(){ var canvas = document.createElement("canvas"); canvas.width = 8; canvas.height = 8; return canvas.toDataURL("image/webp",0.1).indexOf("image/webp") > -1; } if(!canEncode()){ return undefined; } var webmData = null; var clusterTimecode = 0; var clusterCounter = 0; var CLUSTER_MAX_DURATION = 30000; var frameNumber = 0; var width; var height; var frameDelay; var quality; var name; const videoMimeType = "video/webm"; // the only one. const frameMimeType = 'image/webp'; // can be no other const S = String.fromCharCode; const dataTypes = { object : function(data){ return toBlob(data);}, number : function(data){ return stream.num(data);}, string : function(data){ return stream.str(data);}, array : function(data){ return data;}, double2Str : function(num){ var c = new Uint8Array((new Float64Array([num])).buffer); return S(c[7]) + S(c[6]) + S(c[5]) + S(c[4]) + S(c[3]) + S(c[2]) + S(c[1]) + S(c[0]); } }; const stream = { num : function(num){ // writes int var parts = []; while(num > 0){ parts.push(num & 0xff); num = num >> 8; } return new Uint8Array(parts.reverse()); }, str : function(str){ // writes string var i, len, arr; len = str.length; arr = new Uint8Array(len); for(i = 0; i < len; i++){arr[i] = str.charCodeAt(i);} return arr; }, compInt : function(num){ // could not find full details so bit of a guess if(num < 128){ // number is prefixed with a bit (1000 is on byte 0100 two, 0010 three and so on) num += 0x80; return new Uint8Array([num]); }else if(num < 0x4000){ num += 0x4000; return new Uint8Array([num>>8, num]) }else if(num < 0x200000){ num += 0x200000; return new Uint8Array([num>>16, num>>8, num]) }else if(num < 0x10000000){ num += 0x10000000; return new Uint8Array([num>>24, num>>16, num>>8, num]) } } } const ids = { // header names and values videoData : 0x1a45dfa3, Version : 0x4286, ReadVersion : 0x42f7, MaxIDLength : 0x42f2, MaxSizeLength : 0x42f3, DocType : 0x4282, DocTypeVersion : 0x4287, DocTypeReadVersion : 0x4285, Segment : 0x18538067, Info : 0x1549a966, TimecodeScale : 0x2ad7b1, MuxingApp : 0x4d80, WritingApp : 0x5741, Duration : 0x4489, Tracks : 0x1654ae6b, TrackEntry : 0xae, TrackNumber : 0xd7, TrackUID : 0x63c5, FlagLacing : 0x9c, Language : 0x22b59c, CodecID : 0x86, CodecName : 0x258688, TrackType : 0x83, Video : 0xe0, PixelWidth : 0xb0, PixelHeight : 0xba, Cluster : 0x1f43b675, Timecode : 0xe7, Frame : 0xa3, Keyframe : 0x9d012a, FrameBlock : 0x81, }; const keyframeD64Header = '\x9d\x01\x2a'; //VP8 keyframe header 0x9d012a const videoDataPos = 1; // data pos of frame data header const defaultDelay = dataTypes.double2Str(1000/25); const header = [ // structure of webM header/chunks what ever they are called. ids.videoData,[ ids.Version, 1, ids.ReadVersion, 1, ids.MaxIDLength, 4, ids.MaxSizeLength, 8, ids.DocType, 'webm', ids.DocTypeVersion, 2, ids.DocTypeReadVersion, 2 ], ids.Segment, [ ids.Info, [ ids.TimecodeScale, 1000000, ids.MuxingApp, 'Groover', ids.WritingApp, 'Groover', ids.Duration, 0 ], ids.Tracks,[ ids.TrackEntry,[ ids.TrackNumber, 1, ids.TrackUID, 1, ids.FlagLacing, 0, // always o ids.Language, 'und', // undefined I think this means ids.CodecID, 'V_VP8', // These I think must not change ids.CodecName, 'VP8', // These I think must not change ids.TrackType, 1, ids.Video, [ ids.PixelWidth, 0, ids.PixelHeight, 0 ] ] ] ] ]; function getHeader(){ header[3][2][3] = name; header[3][2][5] = name; header[3][2][7] = dataTypes.double2Str(frameDelay); header[3][3][1][15][1] = width; header[3][3][1][15][3] = height; function create(dat){ var i,kv,data; data = []; for(i = 0; i < dat.length; i += 2){ kv = {i : dat[i]}; if(Array.isArray(dat[i + 1])){ kv.d = create(dat[i + 1]); }else{ kv.d = dat[i + 1]; } data.push(kv); } return data; } return create(header); } function addCluster(){ webmData[videoDataPos].d.push({ i: ids.Cluster,d: [{ i: ids.Timecode, d: Math.round(clusterTimecode)}]}); // Fixed bug with Round clusterCounter = 0; } function addFrame(frame){ var VP8, kfS,riff; riff = getWebPChunks(atob(frame.toDataURL(frameMimeType, quality).slice(23))); VP8 = riff.RIFF[0].WEBP[0]; kfS = VP8.indexOf(keyframeD64Header) + 3; frame = { width: ((VP8.charCodeAt(kfS + 1) << 8) | VP8.charCodeAt(kfS)) & 0x3FFF, height: ((VP8.charCodeAt(kfS + 3) << 8) | VP8.charCodeAt(kfS + 2)) & 0x3FFF, data: VP8, riff: riff }; if(clusterCounter > CLUSTER_MAX_DURATION){ addCluster(); } webmData[videoDataPos].d[webmData[videoDataPos].d.length-1].d.push({ i: ids.Frame, d: S(ids.FrameBlock) + S( Math.round(clusterCounter) >> 8) + S( Math.round(clusterCounter) & 0xff) + S(128) + frame.data.slice(4), }); clusterCounter += frameDelay; clusterTimecode += frameDelay; webmData[videoDataPos].d[0].d[3].d = dataTypes.double2Str(clusterTimecode); } function startEncoding(){ frameNumber = clusterCounter = clusterTimecode = 0; webmData = getHeader(); addCluster(); } function toBlob(vidData){ var data,i,vData, len; vData = []; for(i = 0; i < vidData.length; i++){ data = dataTypes[typeof vidData[i].d](vidData[i].d); len = data.size || data.byteLength || data.length; vData.push(stream.num(vidData[i].i)); vData.push(stream.compInt(len)); vData.push(data) } return new Blob(vData, {type: videoMimeType}); } function getWebPChunks(str){ var offset, chunks, id, len, data; offset = 0; chunks = {}; while (offset < str.length) { id = str.substr(offset, 4); // value will have top bit on (bit 32) so not simply a bitwise operation // Warning little endian (Will not work on big endian systems) len = new Uint32Array( new Uint8Array([ str.charCodeAt(offset + 7), str.charCodeAt(offset + 6), str.charCodeAt(offset + 5), str.charCodeAt(offset + 4) ]).buffer)[0]; id = str.substr(offset, 4); chunks[id] = chunks[id] === undefined ? [] : chunks[id]; if (id === 'RIFF' || id === 'LIST') { chunks[id].push(getWebPChunks(str.substr(offset + 8, len))); offset += 8 + len; } else if (id === 'WEBP') { chunks[id].push(str.substr(offset + 8)); break; } else { chunks[id].push(str.substr(offset + 4)); break; } } return chunks; } function Encoder(fps, _quality = 0.8, _name = "Groover"){ this.fps = fps; this.quality = quality = _quality; this.frameDelay = frameDelay = 1000 / fps; this.frame = 0; this.width = width = null; this.timecode = 0; this.name = name = _name; } Encoder.prototype = { addFrame : function(frame){ if('canvas' in frame){ frame = frame.canvas; } if(width === null){ this.width = width = frame.width, this.height = height = frame.height startEncoding(); }else if(width !== frame.width || height !== frame.height){ throw RangeError("Frame size error. Frames must be the same size."); } addFrame(frame); this.frame += 1; this.timecode = clusterTimecode; }, toBlob : function(){ return toBlob(webmData); } } return { Video: Encoder, } })()