| 1 | /** |
| 2 | * A tool for presenting an ArrayBuffer as a stream for writing some simple data types. |
| 3 | * |
| 4 | * By Nicholas Sherlock |
| 5 | * |
| 6 | * Released under the WTFPLv2 https://en.wikipedia.org/wiki/WTFPL |
| 7 | */ |
| 8 | |
| 9 | "use strict"; |
| 10 | |
| 11 | (function(){ |
| 12 | /* |
| 13 | * Create an ArrayBuffer of the given length and present it as a writable stream with methods |
| 14 | * for writing data in different formats. |
| 15 | */ |
| 16 | var ArrayBufferDataStream = function(length) { |
| 17 | this.data = new Uint8Array(length); |
| 18 | this.pos = 0; |
| 19 | }; |
| 20 | |
| 21 | ArrayBufferDataStream.prototype.seek = function(offset) { |
| 22 | this.pos = offset; |
| 23 | }; |
| 24 | |
| 25 | ArrayBufferDataStream.prototype.writeBytes = function(arr) { |
| 26 | for (var i = 0; i < arr.length; i++) { |
| 27 | this.data[this.pos++] = arr[i]; |
| 28 | } |
| 29 | }; |
| 30 | |
| 31 | ArrayBufferDataStream.prototype.writeByte = function(b) { |
| 32 | this.data[this.pos++] = b; |
| 33 | }; |
| 34 | |
| 35 | //Synonym: |
| 36 | ArrayBufferDataStream.prototype.writeU8 = ArrayBufferDataStream.prototype.writeByte; |
| 37 | |
| 38 | ArrayBufferDataStream.prototype.writeU16BE = function(u) { |
| 39 | this.data[this.pos++] = u >> 8; |
| 40 | this.data[this.pos++] = u; |
| 41 | }; |
| 42 | |
| 43 | ArrayBufferDataStream.prototype.writeDoubleBE = function(d) { |
| 44 | var |
| 45 | bytes = new Uint8Array(new Float64Array([d]).buffer); |
| 46 | |
| 47 | for (var i = bytes.length - 1; i >= 0; i--) { |
| 48 | this.writeByte(bytes[i]); |
| 49 | } |
| 50 | }; |
| 51 | |
| 52 | ArrayBufferDataStream.prototype.writeFloatBE = function(d) { |
| 53 | var |
| 54 | bytes = new Uint8Array(new Float32Array([d]).buffer); |
| 55 | |
| 56 | for (var i = bytes.length - 1; i >= 0; i--) { |
| 57 | this.writeByte(bytes[i]); |
| 58 | } |
| 59 | }; |
| 60 | |
| 61 | /** |
| 62 | * Write an ASCII string to the stream |
| 63 | */ |
| 64 | ArrayBufferDataStream.prototype.writeString = function(s) { |
| 65 | for (var i = 0; i < s.length; i++) { |
| 66 | this.data[this.pos++] = s.charCodeAt(i); |
| 67 | } |
| 68 | }; |
| 69 | |
| 70 | /** |
| 71 | * Write the given 32-bit integer to the stream as an EBML variable-length integer using the given byte width |
| 72 | * (use measureEBMLVarInt). |
| 73 | * |
| 74 | * No error checking is performed to ensure that the supplied width is correct for the integer. |
| 75 | * |
| 76 | * @param i Integer to be written |
| 77 | * @param width Number of bytes to write to the stream |
| 78 | */ |
| 79 | ArrayBufferDataStream.prototype.writeEBMLVarIntWidth = function(i, width) { |
| 80 | switch (width) { |
| 81 | case 1: |
| 82 | this.writeU8((1 << 7) | i); |
| 83 | break; |
| 84 | case 2: |
| 85 | this.writeU8((1 << 6) | (i >> 8)); |
| 86 | this.writeU8(i); |
| 87 | break; |
| 88 | case 3: |
| 89 | this.writeU8((1 << 5) | (i >> 16)); |
| 90 | this.writeU8(i >> 8); |
| 91 | this.writeU8(i); |
| 92 | break; |
| 93 | case 4: |
| 94 | this.writeU8((1 << 4) | (i >> 24)); |
| 95 | this.writeU8(i >> 16); |
| 96 | this.writeU8(i >> 8); |
| 97 | this.writeU8(i); |
| 98 | break; |
| 99 | case 5: |
| 100 | /* |
| 101 | * JavaScript converts its doubles to 32-bit integers for bitwise operations, so we need to do a |
| 102 | * division by 2^32 instead of a right-shift of 32 to retain those top 3 bits |
| 103 | */ |
| 104 | this.writeU8((1 << 3) | ((i / 4294967296) & 0x7)); |
| 105 | this.writeU8(i >> 24); |
| 106 | this.writeU8(i >> 16); |
| 107 | this.writeU8(i >> 8); |
| 108 | this.writeU8(i); |
| 109 | break; |
| 110 | default: |
| 111 | throw new RuntimeException("Bad EBML VINT size " + width); |
| 112 | } |
| 113 | }; |
| 114 | |
| 115 | /** |
| 116 | * Return the number of bytes needed to encode the given integer as an EBML VINT. |
| 117 | */ |
| 118 | ArrayBufferDataStream.prototype.measureEBMLVarInt = function(val) { |
| 119 | if (val < (1 << 7) - 1) { |
| 120 | /* Top bit is set, leaving 7 bits to hold the integer, but we can't store 127 because |
| 121 | * "all bits set to one" is a reserved value. Same thing for the other cases below: |
| 122 | */ |
| 123 | return 1; |
| 124 | } else if (val < (1 << 14) - 1) { |
| 125 | return 2; |
| 126 | } else if (val < (1 << 21) - 1) { |
| 127 | return 3; |
| 128 | } else if (val < (1 << 28) - 1) { |
| 129 | return 4; |
| 130 | } else if (val < 34359738367) { // 2 ^ 35 - 1 (can address 32GB) |
| 131 | return 5; |
| 132 | } else { |
| 133 | throw new RuntimeException("EBML VINT size not supported " + val); |
| 134 | } |
| 135 | }; |
| 136 | |
| 137 | ArrayBufferDataStream.prototype.writeEBMLVarInt = function(i) { |
| 138 | this.writeEBMLVarIntWidth(i, this.measureEBMLVarInt(i)); |
| 139 | }; |
| 140 | |
| 141 | /** |
| 142 | * Write the given unsigned 32-bit integer to the stream in big-endian order using the given byte width. |
| 143 | * No error checking is performed to ensure that the supplied width is correct for the integer. |
| 144 | * |
| 145 | * Omit the width parameter to have it determined automatically for you. |
| 146 | * |
| 147 | * @param u Unsigned integer to be written |
| 148 | * @param width Number of bytes to write to the stream |
| 149 | */ |
| 150 | ArrayBufferDataStream.prototype.writeUnsignedIntBE = function(u, width) { |
| 151 | if (width === undefined) { |
| 152 | width = this.measureUnsignedInt(u); |
| 153 | } |
| 154 | |
| 155 | // Each case falls through: |
| 156 | switch (width) { |
| 157 | case 5: |
| 158 | this.writeU8(Math.floor(u / 4294967296)); // Need to use division to access >32 bits of floating point var |
| 159 | case 4: |
| 160 | this.writeU8(u >> 24); |
| 161 | case 3: |
| 162 | this.writeU8(u >> 16); |
| 163 | case 2: |
| 164 | this.writeU8(u >> 8); |
| 165 | case 1: |
| 166 | this.writeU8(u); |
| 167 | break; |
| 168 | default: |
| 169 | throw new RuntimeException("Bad UINT size " + width); |
| 170 | } |
| 171 | }; |
| 172 | |
| 173 | /** |
| 174 | * Return the number of bytes needed to hold the non-zero bits of the given unsigned integer. |
| 175 | */ |
| 176 | ArrayBufferDataStream.prototype.measureUnsignedInt = function(val) { |
| 177 | // Force to 32-bit unsigned integer |
| 178 | if (val < (1 << 8)) { |
| 179 | return 1; |
| 180 | } else if (val < (1 << 16)) { |
| 181 | return 2; |
| 182 | } else if (val < (1 << 24)) { |
| 183 | return 3; |
| 184 | } else if (val < 4294967296) { |
| 185 | return 4; |
| 186 | } else { |
| 187 | return 5; |
| 188 | } |
| 189 | }; |
| 190 | |
| 191 | /** |
| 192 | * Return a view on the portion of the buffer from the beginning to the current seek position as a Uint8Array. |
| 193 | */ |
| 194 | ArrayBufferDataStream.prototype.getAsDataArray = function() { |
| 195 | if (this.pos < this.data.byteLength) { |
| 196 | return this.data.subarray(0, this.pos); |
| 197 | } else if (this.pos == this.data.byteLength) { |
| 198 | return this.data; |
| 199 | } else { |
| 200 | throw "ArrayBufferDataStream's pos lies beyond end of buffer"; |
| 201 | } |
| 202 | }; |
| 203 | |
| 204 | if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') { |
| 205 | module.exports = ArrayBufferDataStream; |
| 206 | } else { |
| 207 | window.ArrayBufferDataStream = ArrayBufferDataStream; |
| 208 | } |
| 209 | }());"use strict"; |
| 210 | |
| 211 | /** |
| 212 | * Allows a series of Blob-convertible objects (ArrayBuffer, Blob, String, etc) to be added to a buffer. Seeking and |
| 213 | * overwriting of blobs is allowed. |
| 214 | * |
| 215 | * You can supply a FileWriter, in which case the BlobBuffer is just used as temporary storage before it writes it |
| 216 | * through to the disk. |
| 217 | * |
| 218 | * By Nicholas Sherlock |
| 219 | * |
| 220 | * Released under the WTFPLv2 https://en.wikipedia.org/wiki/WTFPL |
| 221 | */ |
| 222 | (function() { |
| 223 | var BlobBuffer = function(fs) { |
| 224 | return function(destination) { |
| 225 | var |
| 226 | buffer = [], |
| 227 | writePromise = Promise.resolve(), |
| 228 | fileWriter = null, |
| 229 | fd = null; |
| 230 | |
| 231 | if (typeof FileWriter !== "undefined" && destination instanceof FileWriter) { |
| 232 | fileWriter = destination; |
| 233 | } else if (fs && destination) { |
| 234 | fd = destination; |
| 235 | } |
| 236 | |
| 237 | // Current seek offset |
| 238 | this.pos = 0; |
| 239 | |
| 240 | // One more than the index of the highest byte ever written |
| 241 | this.length = 0; |
| 242 | |
| 243 | // Returns a promise that converts the blob to an ArrayBuffer |
| 244 | function readBlobAsBuffer(blob) { |
| 245 | return new Promise(function (resolve, reject) { |
| 246 | var |
| 247 | reader = new FileReader(); |
| 248 | |
| 249 | reader.addEventListener("loadend", function () { |
| 250 | resolve(reader.result); |
| 251 | }); |
| 252 | |
| 253 | reader.readAsArrayBuffer(blob); |
| 254 | }); |
| 255 | } |
| 256 | |
| 257 | function convertToUint8Array(thing) { |
| 258 | return new Promise(function (resolve, reject) { |
| 259 | if (thing instanceof Uint8Array) { |
| 260 | resolve(thing); |
| 261 | } else if (thing instanceof ArrayBuffer || ArrayBuffer.isView(thing)) { |
| 262 | resolve(new Uint8Array(thing)); |
| 263 | } else if (thing instanceof Blob) { |
| 264 | resolve(readBlobAsBuffer(thing).then(function (buffer) { |
| 265 | return new Uint8Array(buffer); |
| 266 | })); |
| 267 | } else { |
| 268 | //Assume that Blob will know how to read this thing |
| 269 | resolve(readBlobAsBuffer(new Blob([thing])).then(function (buffer) { |
| 270 | return new Uint8Array(buffer); |
| 271 | })); |
| 272 | } |
| 273 | }); |
| 274 | } |
| 275 | |
| 276 | function measureData(data) { |
| 277 | var |
| 278 | result = data.byteLength || data.length || data.size; |
| 279 | |
| 280 | if (!Number.isInteger(result)) { |
| 281 | throw "Failed to determine size of element"; |
| 282 | } |
| 283 | |
| 284 | return result; |
| 285 | } |
| 286 | |
| 287 | /** |
| 288 | * Seek to the given absolute offset. |
| 289 | * |
| 290 | * You may not seek beyond the end of the file (this would create a hole and/or allow blocks to be written in non- |
| 291 | * sequential order, which isn't currently supported by the memory buffer backend). |
| 292 | */ |
| 293 | this.seek = function (offset) { |
| 294 | if (offset < 0) { |
| 295 | throw "Offset may not be negative"; |
| 296 | } |
| 297 | |
| 298 | if (isNaN(offset)) { |
| 299 | throw "Offset may not be NaN"; |
| 300 | } |
| 301 | |
| 302 | if (offset > this.length) { |
| 303 | throw "Seeking beyond the end of file is not allowed"; |
| 304 | } |
| 305 | |
| 306 | this.pos = offset; |
| 307 | }; |
| 308 | |
| 309 | /** |
| 310 | * Write the Blob-convertible data to the buffer at the current seek position. |
| 311 | * |
| 312 | * Note: If overwriting existing data, the write must not cross preexisting block boundaries (written data must |
| 313 | * be fully contained by the extent of a previous write). |
| 314 | */ |
| 315 | this.write = function (data) { |
| 316 | var |
| 317 | newEntry = { |
| 318 | offset: this.pos, |
| 319 | data: data, |
| 320 | length: measureData(data) |
| 321 | }, |
| 322 | isAppend = newEntry.offset >= this.length; |
| 323 | |
| 324 | this.pos += newEntry.length; |
| 325 | this.length = Math.max(this.length, this.pos); |
| 326 | |
| 327 | // After previous writes complete, perform our write |
| 328 | writePromise = writePromise.then(function () { |
| 329 | if (fd) { |
| 330 | return new Promise(function(resolve, reject) { |
| 331 | convertToUint8Array(newEntry.data).then(function(dataArray) { |
| 332 | var |
| 333 | totalWritten = 0, |
| 334 | buffer = Buffer.from(dataArray.buffer), |
| 335 | |
| 336 | handleWriteComplete = function(err, written, buffer) { |
| 337 | totalWritten += written; |
| 338 | |
| 339 | if (totalWritten >= buffer.length) { |
| 340 | resolve(); |
| 341 | } else { |
| 342 | // We still have more to write... |
| 343 | fs.write(fd, buffer, totalWritten, buffer.length - totalWritten, newEntry.offset + totalWritten, handleWriteComplete); |
| 344 | } |
| 345 | }; |
| 346 | |
| 347 | fs.write(fd, buffer, 0, buffer.length, newEntry.offset, handleWriteComplete); |
| 348 | }); |
| 349 | }); |
| 350 | } else if (fileWriter) { |
| 351 | return new Promise(function (resolve, reject) { |
| 352 | fileWriter.onwriteend = resolve; |
| 353 | |
| 354 | fileWriter.seek(newEntry.offset); |
| 355 | fileWriter.write(new Blob([newEntry.data])); |
| 356 | }); |
| 357 | } else if (!isAppend) { |
| 358 | // We might be modifying a write that was already buffered in memory. |
| 359 | |
| 360 | // Slow linear search to find a block we might be overwriting |
| 361 | for (var i = 0; i < buffer.length; i++) { |
| 362 | var |
| 363 | entry = buffer[i]; |
| 364 | |
| 365 | // If our new entry overlaps the old one in any way... |
| 366 | if (!(newEntry.offset + newEntry.length <= entry.offset || newEntry.offset >= entry.offset + entry.length)) { |
| 367 | if (newEntry.offset < entry.offset || newEntry.offset + newEntry.length > entry.offset + entry.length) { |
| 368 | throw new Error("Overwrite crosses blob boundaries"); |
| 369 | } |
| 370 | |
| 371 | if (newEntry.offset == entry.offset && newEntry.length == entry.length) { |
| 372 | // We overwrote the entire block |
| 373 | entry.data = newEntry.data; |
| 374 | |
| 375 | // We're done |
| 376 | return; |
| 377 | } else { |
| 378 | return convertToUint8Array(entry.data) |
| 379 | .then(function (entryArray) { |
| 380 | entry.data = entryArray; |
| 381 | |
| 382 | return convertToUint8Array(newEntry.data); |
| 383 | }).then(function (newEntryArray) { |
| 384 | newEntry.data = newEntryArray; |
| 385 | |
| 386 | entry.data.set(newEntry.data, newEntry.offset - entry.offset); |
| 387 | }); |
| 388 | } |
| 389 | } |
| 390 | } |
| 391 | // Else fall through to do a simple append, as we didn't overwrite any pre-existing blocks |
| 392 | } |
| 393 | |
| 394 | buffer.push(newEntry); |
| 395 | }); |
| 396 | }; |
| 397 | |
| 398 | /** |
| 399 | * Finish all writes to the buffer, returning a promise that signals when that is complete. |
| 400 | * |
| 401 | * If a FileWriter was not provided, the promise is resolved with a Blob that represents the completed BlobBuffer |
| 402 | * contents. You can optionally pass in a mimeType to be used for this blob. |
| 403 | * |
| 404 | * If a FileWriter was provided, the promise is resolved with null as the first argument. |
| 405 | */ |
| 406 | this.complete = function (mimeType) { |
| 407 | if (fd || fileWriter) { |
| 408 | writePromise = writePromise.then(function () { |
| 409 | return null; |
| 410 | }); |
| 411 | } else { |
| 412 | // After writes complete we need to merge the buffer to give to the caller |
| 413 | writePromise = writePromise.then(function () { |
| 414 | var |
| 415 | result = []; |
| 416 | |
| 417 | for (var i = 0; i < buffer.length; i++) { |
| 418 | result.push(buffer[i].data); |
| 419 | } |
| 420 | |
| 421 | return new Blob(result, {mimeType: mimeType}); |
| 422 | }); |
| 423 | } |
| 424 | |
| 425 | return writePromise; |
| 426 | }; |
| 427 | }; |
| 428 | }; |
| 429 | |
| 430 | if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') { |
| 431 | module.exports = BlobBuffer(require('fs')); |
| 432 | } else { |
| 433 | window.BlobBuffer = BlobBuffer(null); |
| 434 | } |
| 435 | })();/** |
| 436 | * WebM video encoder for Google Chrome. This implementation is suitable for creating very large video files, because |
| 437 | * it can stream Blobs directly to a FileWriter without buffering the entire video in memory. |
| 438 | * |
| 439 | * When FileWriter is not available or not desired, it can buffer the video in memory as a series of Blobs which are |
| 440 | * eventually returned as one composite Blob. |
| 441 | * |
| 442 | * By Nicholas Sherlock. |
| 443 | * |
| 444 | * Based on the ideas from Whammy: https://github.com/antimatter15/whammy |
| 445 | * |
| 446 | * Released under the WTFPLv2 https://en.wikipedia.org/wiki/WTFPL |
| 447 | */ |
| 448 | |
| 449 | "use strict"; |
| 450 | |
| 451 | (function() { |
| 452 | var WebMWriter = function(ArrayBufferDataStream, BlobBuffer) { |
| 453 | function extend(base, top) { |
| 454 | var |
| 455 | target = {}; |
| 456 | |
| 457 | [base, top].forEach(function(obj) { |
| 458 | for (var prop in obj) { |
| 459 | if (Object.prototype.hasOwnProperty.call(obj, prop)) { |
| 460 | target[prop] = obj[prop]; |
| 461 | } |
| 462 | } |
| 463 | }); |
| 464 | |
| 465 | return target; |
| 466 | } |
| 467 | |
| 468 | /** |
| 469 | * Decode a Base64 data URL into a binary string. |
| 470 | * |
| 471 | * Returns the binary string, or false if the URL could not be decoded. |
| 472 | */ |
| 473 | function decodeBase64WebPDataURL(url) { |
| 474 | if (typeof url !== "string" || !url.match(/^data:image\/webp;base64,/i)) { |
| 475 | return false; |
| 476 | } |
| 477 | |
| 478 | return window.atob(url.substring("data:image\/webp;base64,".length)); |
| 479 | } |
| 480 | |
| 481 | /** |
| 482 | * Convert a raw binary string (one character = one output byte) to an ArrayBuffer |
| 483 | */ |
| 484 | function stringToArrayBuffer(string) { |
| 485 | var |
| 486 | buffer = new ArrayBuffer(string.length), |
| 487 | int8Array = new Uint8Array(buffer); |
| 488 | |
| 489 | for (var i = 0; i < string.length; i++) { |
| 490 | int8Array[i] = string.charCodeAt(i); |
| 491 | } |
| 492 | |
| 493 | return buffer; |
| 494 | } |
| 495 | |
| 496 | /** |
| 497 | * Convert the given canvas to a WebP encoded image and return the image data as a string. |
| 498 | */ |
| 499 | function renderAsWebP(canvas, quality) { |
| 500 | var |
| 501 | frame = canvas.toDataURL('image/webp', quality); |
| 502 | |
| 503 | return decodeBase64WebPDataURL(frame); |
| 504 | } |
| 505 | |
| 506 | function extractKeyframeFromWebP(webP) { |
| 507 | // Assume that Chrome will generate a Simple Lossy WebP which has this header: |
| 508 | var |
| 509 | keyframeStartIndex = webP.indexOf('VP8 '); |
| 510 | |
| 511 | if (keyframeStartIndex == -1) { |
| 512 | throw "Failed to identify beginning of keyframe in WebP image"; |
| 513 | } |
| 514 | |
| 515 | // Skip the header and the 4 bytes that encode the length of the VP8 chunk |
| 516 | keyframeStartIndex += 'VP8 '.length + 4; |
| 517 | |
| 518 | return webP.substring(keyframeStartIndex); |
| 519 | } |
| 520 | |
| 521 | // Just a little utility so we can tag values as floats for the EBML encoder's benefit |
| 522 | function EBMLFloat32(value) { |
| 523 | this.value = value; |
| 524 | } |
| 525 | |
| 526 | function EBMLFloat64(value) { |
| 527 | this.value = value; |
| 528 | } |
| 529 | |
| 530 | /** |
| 531 | * Write the given EBML object to the provided ArrayBufferStream. |
| 532 | * |
| 533 | * The buffer's first byte is at bufferFileOffset inside the video file. This is used to complete offset and |
| 534 | * dataOffset fields in each EBML structure, indicating the file offset of the first byte of the EBML element and |
| 535 | * its data payload. |
| 536 | */ |
| 537 | function writeEBML(buffer, bufferFileOffset, ebml) { |
| 538 | // Is the ebml an array of sibling elements? |
| 539 | if (Array.isArray(ebml)) { |
| 540 | for (var i = 0; i < ebml.length; i++) { |
| 541 | writeEBML(buffer, bufferFileOffset, ebml[i]); |
| 542 | } |
| 543 | // Is this some sort of raw data that we want to write directly? |
| 544 | } else if (typeof ebml === "string") { |
| 545 | buffer.writeString(ebml); |
| 546 | } else if (ebml instanceof Uint8Array) { |
| 547 | buffer.writeBytes(ebml); |
| 548 | } else if (ebml.id){ |
| 549 | // We're writing an EBML element |
| 550 | ebml.offset = buffer.pos + bufferFileOffset; |
| 551 | |
| 552 | buffer.writeUnsignedIntBE(ebml.id); // ID field |
| 553 | |
| 554 | // Now we need to write the size field, so we must know the payload size: |
| 555 | |
| 556 | if (Array.isArray(ebml.data)) { |
| 557 | // Writing an array of child elements. We won't try to measure the size of the children up-front |
| 558 | |
| 559 | var |
| 560 | sizePos, dataBegin, dataEnd; |
| 561 | |
| 562 | if (ebml.size === -1) { |
| 563 | // Write the reserved all-one-bits marker to note that the size of this element is unknown/unbounded |
| 564 | buffer.writeByte(0xFF); |
| 565 | } else { |
| 566 | sizePos = buffer.pos; |
| 567 | |
| 568 | /* Write a dummy size field to overwrite later. 4 bytes allows an element maximum size of 256MB, |
| 569 | * which should be plenty (we don't want to have to buffer that much data in memory at one time |
| 570 | * anyway!) |
| 571 | */ |
| 572 | buffer.writeBytes([0, 0, 0, 0]); |
| 573 | } |
| 574 | |
| 575 | dataBegin = buffer.pos; |
| 576 | |
| 577 | ebml.dataOffset = dataBegin + bufferFileOffset; |
| 578 | writeEBML(buffer, bufferFileOffset, ebml.data); |
| 579 | |
| 580 | if (ebml.size !== -1) { |
| 581 | dataEnd = buffer.pos; |
| 582 | |
| 583 | ebml.size = dataEnd - dataBegin; |
| 584 | |
| 585 | buffer.seek(sizePos); |
| 586 | buffer.writeEBMLVarIntWidth(ebml.size, 4); // Size field |
| 587 | |
| 588 | buffer.seek(dataEnd); |
| 589 | } |
| 590 | } else if (typeof ebml.data === "string") { |
| 591 | buffer.writeEBMLVarInt(ebml.data.length); // Size field |
| 592 | ebml.dataOffset = buffer.pos + bufferFileOffset; |
| 593 | buffer.writeString(ebml.data); |
| 594 | } else if (typeof ebml.data === "number") { |
| 595 | // Allow the caller to explicitly choose the size if they wish by supplying a size field |
| 596 | if (!ebml.size) { |
| 597 | ebml.size = buffer.measureUnsignedInt(ebml.data); |
| 598 | } |
| 599 | |
| 600 | buffer.writeEBMLVarInt(ebml.size); // Size field |
| 601 | ebml.dataOffset = buffer.pos + bufferFileOffset; |
| 602 | buffer.writeUnsignedIntBE(ebml.data, ebml.size); |
| 603 | } else if (ebml.data instanceof EBMLFloat64) { |
| 604 | buffer.writeEBMLVarInt(8); // Size field |
| 605 | ebml.dataOffset = buffer.pos + bufferFileOffset; |
| 606 | buffer.writeDoubleBE(ebml.data.value); |
| 607 | } else if (ebml.data instanceof EBMLFloat32) { |
| 608 | buffer.writeEBMLVarInt(4); // Size field |
| 609 | ebml.dataOffset = buffer.pos + bufferFileOffset; |
| 610 | buffer.writeFloatBE(ebml.data.value); |
| 611 | } else if (ebml.data instanceof Uint8Array) { |
| 612 | buffer.writeEBMLVarInt(ebml.data.byteLength); // Size field |
| 613 | ebml.dataOffset = buffer.pos + bufferFileOffset; |
| 614 | buffer.writeBytes(ebml.data); |
| 615 | } else { |
| 616 | throw "Bad EBML datatype " + typeof ebml.data; |
| 617 | } |
| 618 | } else { |
| 619 | throw "Bad EBML datatype " + typeof ebml.data; |
| 620 | } |
| 621 | } |
| 622 | |
| 623 | return function(options) { |
| 624 | var |
| 625 | MAX_CLUSTER_DURATION_MSEC = 5000, |
| 626 | DEFAULT_TRACK_NUMBER = 1, |
| 627 | |
| 628 | writtenHeader = false, |
| 629 | videoWidth, videoHeight, |
| 630 | |
| 631 | clusterFrameBuffer = [], |
| 632 | clusterStartTime = 0, |
| 633 | clusterDuration = 0, |
| 634 | |
| 635 | optionDefaults = { |
| 636 | quality: 0.95, // WebM image quality from 0.0 (worst) to 1.0 (best) |
| 637 | fileWriter: null, // Chrome FileWriter in order to stream to a file instead of buffering to memory (optional) |
| 638 | fd: null, // Node.JS file descriptor to write to instead of buffering (optional) |
| 639 | |
| 640 | // You must supply one of: |
| 641 | frameDuration: null, // Duration of frames in milliseconds |
| 642 | frameRate: null, // Number of frames per second |
| 643 | }, |
| 644 | |
| 645 | seekPoints = { |
| 646 | Cues: {id: new Uint8Array([0x1C, 0x53, 0xBB, 0x6B]), positionEBML: null}, |
| 647 | SegmentInfo: {id: new Uint8Array([0x15, 0x49, 0xA9, 0x66]), positionEBML: null}, |
| 648 | Tracks: {id: new Uint8Array([0x16, 0x54, 0xAE, 0x6B]), positionEBML: null}, |
| 649 | }, |
| 650 | |
| 651 | ebmlSegment, |
| 652 | segmentDuration = { |
| 653 | "id": 0x4489, // Duration |
| 654 | "data": new EBMLFloat64(0) |
| 655 | }, |
| 656 | |
| 657 | seekHead, |
| 658 | |
| 659 | cues = [], |
| 660 | |
| 661 | blobBuffer = new BlobBuffer(options.fileWriter || options.fd); |
| 662 | |
| 663 | function fileOffsetToSegmentRelative(fileOffset) { |
| 664 | return fileOffset - ebmlSegment.dataOffset; |
| 665 | } |
| 666 | |
| 667 | /** |
| 668 | * Create a SeekHead element with descriptors for the points in the global seekPoints array. |
| 669 | * |
| 670 | * 5 bytes of position values are reserved for each node, which lie at the offset point.positionEBML.dataOffset, |
| 671 | * to be overwritten later. |
| 672 | */ |
| 673 | function createSeekHead() { |
| 674 | var |
| 675 | seekPositionEBMLTemplate = { |
| 676 | "id": 0x53AC, // SeekPosition |
| 677 | "size": 5, // Allows for 32GB video files |
| 678 | "data": 0 // We'll overwrite this when the file is complete |
| 679 | }, |
| 680 | |
| 681 | result = { |
| 682 | "id": 0x114D9B74, // SeekHead |
| 683 | "data": [] |
| 684 | }; |
| 685 | |
| 686 | for (var name in seekPoints) { |
| 687 | var |
| 688 | seekPoint = seekPoints[name]; |
| 689 | |
| 690 | seekPoint.positionEBML = Object.create(seekPositionEBMLTemplate); |
| 691 | |
| 692 | result.data.push({ |
| 693 | "id": 0x4DBB, // Seek |
| 694 | "data": [ |
| 695 | { |
| 696 | "id": 0x53AB, // SeekID |
| 697 | "data": seekPoint.id |
| 698 | }, |
| 699 | seekPoint.positionEBML |
| 700 | ] |
| 701 | }); |
| 702 | } |
| 703 | |
| 704 | return result; |
| 705 | } |
| 706 | |
| 707 | /** |
| 708 | * Write the WebM file header to the stream. |
| 709 | */ |
| 710 | function writeHeader() { |
| 711 | seekHead = createSeekHead(); |
| 712 | |
| 713 | var |
| 714 | ebmlHeader = { |
| 715 | "id": 0x1a45dfa3, // EBML |
| 716 | "data": [ |
| 717 | { |
| 718 | "id": 0x4286, // EBMLVersion |
| 719 | "data": 1 |
| 720 | }, |
| 721 | { |
| 722 | "id": 0x42f7, // EBMLReadVersion |
| 723 | "data": 1 |
| 724 | }, |
| 725 | { |
| 726 | "id": 0x42f2, // EBMLMaxIDLength |
| 727 | "data": 4 |
| 728 | }, |
| 729 | { |
| 730 | "id": 0x42f3, // EBMLMaxSizeLength |
| 731 | "data": 8 |
| 732 | }, |
| 733 | { |
| 734 | "id": 0x4282, // DocType |
| 735 | "data": "webm" |
| 736 | }, |
| 737 | { |
| 738 | "id": 0x4287, // DocTypeVersion |
| 739 | "data": 2 |
| 740 | }, |
| 741 | { |
| 742 | "id": 0x4285, // DocTypeReadVersion |
| 743 | "data": 2 |
| 744 | } |
| 745 | ] |
| 746 | }, |
| 747 | |
| 748 | segmentInfo = { |
| 749 | "id": 0x1549a966, // Info |
| 750 | "data": [ |
| 751 | { |
| 752 | "id": 0x2ad7b1, // TimecodeScale |
| 753 | "data": 1e6 // Times will be in miliseconds (1e6 nanoseconds per step = 1ms) |
| 754 | }, |
| 755 | { |
| 756 | "id": 0x4d80, // MuxingApp |
| 757 | "data": "webm-writer-js", |
| 758 | }, |
| 759 | { |
| 760 | "id": 0x5741, // WritingApp |
| 761 | "data": "webm-writer-js" |
| 762 | }, |
| 763 | segmentDuration // To be filled in later |
| 764 | ] |
| 765 | }, |
| 766 | |
| 767 | tracks = { |
| 768 | "id": 0x1654ae6b, // Tracks |
| 769 | "data": [ |
| 770 | { |
| 771 | "id": 0xae, // TrackEntry |
| 772 | "data": [ |
| 773 | { |
| 774 | "id": 0xd7, // TrackNumber |
| 775 | "data": DEFAULT_TRACK_NUMBER |
| 776 | }, |
| 777 | { |
| 778 | "id": 0x73c5, // TrackUID |
| 779 | "data": DEFAULT_TRACK_NUMBER |
| 780 | }, |
| 781 | { |
| 782 | "id": 0x9c, // FlagLacing |
| 783 | "data": 0 |
| 784 | }, |
| 785 | { |
| 786 | "id": 0x22b59c, // Language |
| 787 | "data": "und" |
| 788 | }, |
| 789 | { |
| 790 | "id": 0x86, // CodecID |
| 791 | "data": "V_VP8" |
| 792 | }, |
| 793 | { |
| 794 | "id": 0x258688, // CodecName |
| 795 | "data": "VP8" |
| 796 | }, |
| 797 | { |
| 798 | "id": 0x83, // TrackType |
| 799 | "data": 1 |
| 800 | }, |
| 801 | { |
| 802 | "id": 0xe0, // Video |
| 803 | "data": [ |
| 804 | { |
| 805 | "id": 0xb0, // PixelWidth |
| 806 | "data": videoWidth |
| 807 | }, |
| 808 | { |
| 809 | "id": 0xba, // PixelHeight |
| 810 | "data": videoHeight |
| 811 | } |
| 812 | ] |
| 813 | } |
| 814 | ] |
| 815 | } |
| 816 | ] |
| 817 | }; |
| 818 | |
| 819 | ebmlSegment = { |
| 820 | "id": 0x18538067, // Segment |
| 821 | "size": -1, // Unbounded size |
| 822 | "data": [ |
| 823 | seekHead, |
| 824 | segmentInfo, |
| 825 | tracks, |
| 826 | ] |
| 827 | }; |
| 828 | |
| 829 | var |
| 830 | bufferStream = new ArrayBufferDataStream(256); |
| 831 | |
| 832 | writeEBML(bufferStream, blobBuffer.pos, [ebmlHeader, ebmlSegment]); |
| 833 | blobBuffer.write(bufferStream.getAsDataArray()); |
| 834 | |
| 835 | // Now we know where these top-level elements lie in the file: |
| 836 | seekPoints.SegmentInfo.positionEBML.data = fileOffsetToSegmentRelative(segmentInfo.offset); |
| 837 | seekPoints.Tracks.positionEBML.data = fileOffsetToSegmentRelative(tracks.offset); |
| 838 | }; |
| 839 | |
| 840 | /** |
| 841 | * Create a SimpleBlock keyframe header using these fields: |
| 842 | * timecode - Time of this keyframe |
| 843 | * trackNumber - Track number from 1 to 126 (inclusive) |
| 844 | * frame - Raw frame data payload string |
| 845 | * |
| 846 | * Returns an EBML element. |
| 847 | */ |
| 848 | function createKeyframeBlock(keyframe) { |
| 849 | var |
| 850 | bufferStream = new ArrayBufferDataStream(1 + 2 + 1); |
| 851 | |
| 852 | if (!(keyframe.trackNumber > 0 && keyframe.trackNumber < 127)) { |
| 853 | throw "TrackNumber must be > 0 and < 127"; |
| 854 | } |
| 855 | |
| 856 | bufferStream.writeEBMLVarInt(keyframe.trackNumber); // Always 1 byte since we limit the range of trackNumber |
| 857 | bufferStream.writeU16BE(keyframe.timecode); |
| 858 | |
| 859 | // Flags byte |
| 860 | bufferStream.writeByte( |
| 861 | 1 << 7 // Keyframe |
| 862 | ); |
| 863 | |
| 864 | return { |
| 865 | "id": 0xA3, // SimpleBlock |
| 866 | "data": [ |
| 867 | bufferStream.getAsDataArray(), |
| 868 | keyframe.frame |
| 869 | ] |
| 870 | }; |
| 871 | } |
| 872 | |
| 873 | /** |
| 874 | * Create a Cluster node using these fields: |
| 875 | * |
| 876 | * timecode - Start time for the cluster |
| 877 | * |
| 878 | * Returns an EBML element. |
| 879 | */ |
| 880 | function createCluster(cluster) { |
| 881 | return { |
| 882 | "id": 0x1f43b675, |
| 883 | "data": [ |
| 884 | { |
| 885 | "id": 0xe7, // Timecode |
| 886 | "data": Math.round(cluster.timecode) |
| 887 | } |
| 888 | ] |
| 889 | }; |
| 890 | } |
| 891 | |
| 892 | function addCuePoint(trackIndex, clusterTime, clusterFileOffset) { |
| 893 | cues.push({ |
| 894 | "id": 0xBB, // Cue |
| 895 | "data": [ |
| 896 | { |
| 897 | "id": 0xB3, // CueTime |
| 898 | "data": clusterTime |
| 899 | }, |
| 900 | { |
| 901 | "id": 0xB7, // CueTrackPositions |
| 902 | "data": [ |
| 903 | { |
| 904 | "id": 0xF7, // CueTrack |
| 905 | "data": trackIndex |
| 906 | }, |
| 907 | { |
| 908 | "id": 0xF1, // CueClusterPosition |
| 909 | "data": fileOffsetToSegmentRelative(clusterFileOffset) |
| 910 | } |
| 911 | ] |
| 912 | } |
| 913 | ] |
| 914 | }); |
| 915 | } |
| 916 | |
| 917 | /** |
| 918 | * Write a Cues element to the blobStream using the global `cues` array of CuePoints (use addCuePoint()). |
| 919 | * The seek entry for the Cues in the SeekHead is updated. |
| 920 | */ |
| 921 | function writeCues() { |
| 922 | var |
| 923 | ebml = { |
| 924 | "id": 0x1C53BB6B, |
| 925 | "data": cues |
| 926 | }, |
| 927 | |
| 928 | cuesBuffer = new ArrayBufferDataStream(16 + cues.length * 32); // Pretty crude estimate of the buffer size we'll need |
| 929 | |
| 930 | writeEBML(cuesBuffer, blobBuffer.pos, ebml); |
| 931 | blobBuffer.write(cuesBuffer.getAsDataArray()); |
| 932 | |
| 933 | // Now we know where the Cues element has ended up, we can update the SeekHead |
| 934 | seekPoints.Cues.positionEBML.data = fileOffsetToSegmentRelative(ebml.offset); |
| 935 | } |
| 936 | |
| 937 | /** |
| 938 | * Flush the frames in the current clusterFrameBuffer out to the stream as a Cluster. |
| 939 | */ |
| 940 | function flushClusterFrameBuffer() { |
| 941 | if (clusterFrameBuffer.length == 0) { |
| 942 | return; |
| 943 | } |
| 944 | |
| 945 | // First work out how large of a buffer we need to hold the cluster data |
| 946 | var |
| 947 | rawImageSize = 0; |
| 948 | |
| 949 | for (var i = 0; i < clusterFrameBuffer.length; i++) { |
| 950 | rawImageSize += clusterFrameBuffer[i].frame.length; |
| 951 | } |
| 952 | |
| 953 | var |
| 954 | buffer = new ArrayBufferDataStream(rawImageSize + clusterFrameBuffer.length * 32), // Estimate 32 bytes per SimpleBlock header |
| 955 | |
| 956 | cluster = createCluster({ |
| 957 | timecode: Math.round(clusterStartTime), |
| 958 | }); |
| 959 | |
| 960 | for (var i = 0; i < clusterFrameBuffer.length; i++) { |
| 961 | cluster.data.push(createKeyframeBlock(clusterFrameBuffer[i])); |
| 962 | } |
| 963 | |
| 964 | writeEBML(buffer, blobBuffer.pos, cluster); |
| 965 | blobBuffer.write(buffer.getAsDataArray()); |
| 966 | |
| 967 | addCuePoint(DEFAULT_TRACK_NUMBER, Math.round(clusterStartTime), cluster.offset); |
| 968 | |
| 969 | clusterFrameBuffer = []; |
| 970 | clusterStartTime += clusterDuration; |
| 971 | clusterDuration = 0; |
| 972 | } |
| 973 | |
| 974 | function validateOptions() { |
| 975 | // Derive frameDuration setting if not already supplied |
| 976 | if (!options.frameDuration) { |
| 977 | if (options.frameRate) { |
| 978 | options.frameDuration = 1000 / options.frameRate; |
| 979 | } else { |
| 980 | throw "Missing required frameDuration or frameRate setting"; |
| 981 | } |
| 982 | } |
| 983 | } |
| 984 | |
| 985 | function addFrameToCluster(frame) { |
| 986 | frame.trackNumber = DEFAULT_TRACK_NUMBER; |
| 987 | |
| 988 | // Frame timecodes are relative to the start of their cluster: |
| 989 | frame.timecode = Math.round(clusterDuration); |
| 990 | |
| 991 | clusterFrameBuffer.push(frame); |
| 992 | |
| 993 | clusterDuration += frame.duration; |
| 994 | |
| 995 | if (clusterDuration >= MAX_CLUSTER_DURATION_MSEC) { |
| 996 | flushClusterFrameBuffer(); |
| 997 | } |
| 998 | } |
| 999 | |
| 1000 | /** |
| 1001 | * Rewrites the SeekHead element that was initially written to the stream with the offsets of top level elements. |
| 1002 | * |
| 1003 | * Call once writing is complete (so the offset of all top level elements is known). |
| 1004 | */ |
| 1005 | function rewriteSeekHead() { |
| 1006 | var |
| 1007 | seekHeadBuffer = new ArrayBufferDataStream(seekHead.size), |
| 1008 | oldPos = blobBuffer.pos; |
| 1009 | |
| 1010 | // Write the rewritten SeekHead element's data payload to the stream (don't need to update the id or size) |
| 1011 | writeEBML(seekHeadBuffer, seekHead.dataOffset, seekHead.data); |
| 1012 | |
| 1013 | // And write that through to the file |
| 1014 | blobBuffer.seek(seekHead.dataOffset); |
| 1015 | blobBuffer.write(seekHeadBuffer.getAsDataArray()); |
| 1016 | |
| 1017 | blobBuffer.seek(oldPos); |
| 1018 | } |
| 1019 | |
| 1020 | /** |
| 1021 | * Rewrite the Duration field of the Segment with the newly-discovered video duration. |
| 1022 | */ |
| 1023 | function rewriteDuration() { |
| 1024 | var |
| 1025 | buffer = new ArrayBufferDataStream(8), |
| 1026 | oldPos = blobBuffer.pos; |
| 1027 | |
| 1028 | // Rewrite the data payload (don't need to update the id or size) |
| 1029 | buffer.writeDoubleBE(clusterStartTime); |
| 1030 | |
| 1031 | // And write that through to the file |
| 1032 | blobBuffer.seek(segmentDuration.dataOffset); |
| 1033 | blobBuffer.write(buffer.getAsDataArray()); |
| 1034 | |
| 1035 | blobBuffer.seek(oldPos); |
| 1036 | } |
| 1037 | |
| 1038 | /** |
| 1039 | * Add a frame to the video. Currently the frame must be a Canvas element. |
| 1040 | */ |
| 1041 | this.addFrame = function(canvas, duration) { |
| 1042 | //if (writtenHeader) { |
| 1043 | // if (canvas.width != videoWidth || canvas.height != videoHeight) { |
| 1044 | // throw "Frame size differs from previous frames"; |
| 1045 | // } |
| 1046 | //} else { |
| 1047 | videoWidth = canvas.width; |
| 1048 | videoHeight = canvas.height; |
| 1049 | |
| 1050 | writeHeader(); |
| 1051 | writtenHeader = true; |
| 1052 | //} |
| 1053 | |
| 1054 | var |
| 1055 | webP = renderAsWebP(canvas, options.quality); |
| 1056 | |
| 1057 | if (!webP) { |
| 1058 | throw "Couldn't decode WebP frame, does the browser support WebP?"; |
| 1059 | } |
| 1060 | |
| 1061 | addFrameToCluster({ |
| 1062 | frame: extractKeyframeFromWebP(webP), |
| 1063 | duration: ((typeof duration == 'number')?duration:options.frameDuration) |
| 1064 | }); |
| 1065 | }; |
| 1066 | |
| 1067 | /** |
| 1068 | * Finish writing the video and return a Promise to signal completion. |
| 1069 | * |
| 1070 | * If the destination device was memory (i.e. options.fileWriter was not supplied), the Promise is resolved with |
| 1071 | * a Blob with the contents of the entire video. |
| 1072 | */ |
| 1073 | this.complete = function() { |
| 1074 | flushClusterFrameBuffer(); |
| 1075 | |
| 1076 | writeCues(); |
| 1077 | rewriteSeekHead(); |
| 1078 | rewriteDuration(); |
| 1079 | |
| 1080 | return blobBuffer.complete('video/webm'); |
| 1081 | }; |
| 1082 | |
| 1083 | this.getWrittenSize = function() { |
| 1084 | return blobBuffer.length; |
| 1085 | }; |
| 1086 | |
| 1087 | options = extend(optionDefaults, options || {}); |
| 1088 | validateOptions(); |
| 1089 | }; |
| 1090 | }; |
| 1091 | |
| 1092 | if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') { |
| 1093 | module.exports = WebMWriter(require("./ArrayBufferDataStream"), require("./BlobBuffer")); |
| 1094 | } else { |
| 1095 | window.WebMWriter = WebMWriter(ArrayBufferDataStream, BlobBuffer); |
| 1096 | } |
| 1097 | })(); |