VP8 raw file: JavaScript parsing library

IVF is a simple container format for raw VP8 data, which is an open and royalty-free video compression format, currently developed by Google.

Test .ivf files are available at https://chromium.googlesource.com/webm/vp8-test-vectors

File extension

ivf

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.7

References

This page hosts a formal specification of VP8 raw file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.

The JavaScript runtime library is available at npm:

npm install kaitai-struct

Code

See the usage examples in the JavaScript notes.

Parse structure from an ArrayBuffer:

var arrayBuffer = ...;
var data = new Vp8Ivf(new KaitaiStream(arrayBuffer));

After that, one can get various attributes from the structure by accessing fields or properties like:

data.magic1 // => Magic Number of IVF Files

JavaScript source code to parse VP8 raw file

Vp8Ivf.js

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['kaitai-struct/KaitaiStream'], factory);
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory(require('kaitai-struct/KaitaiStream'));
  } else {
    root.Vp8Ivf = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
/**
 * IVF is a simple container format for raw VP8 data, which is an open
 * and royalty-free video compression format, currently developed by
 * Google.
 * 
 * Test .ivf files are available at https://chromium.googlesource.com/webm/vp8-test-vectors
 * @see {@link https://wiki.multimedia.cx/index.php/IVF|Source}
 */

var Vp8Ivf = (function() {
  function Vp8Ivf(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  Vp8Ivf.prototype._read = function() {
    this.magic1 = this._io.readBytes(4);
    if (!((KaitaiStream.byteArrayCompare(this.magic1, [68, 75, 73, 70]) == 0))) {
      throw new KaitaiStream.ValidationNotEqualError([68, 75, 73, 70], this.magic1, this._io, "/seq/0");
    }
    this.version = this._io.readU2le();
    this.lenHeader = this._io.readU2le();
    this.codec = this._io.readBytes(4);
    if (!((KaitaiStream.byteArrayCompare(this.codec, [86, 80, 56, 48]) == 0))) {
      throw new KaitaiStream.ValidationNotEqualError([86, 80, 56, 48], this.codec, this._io, "/seq/3");
    }
    this.width = this._io.readU2le();
    this.height = this._io.readU2le();
    this.framerate = this._io.readU4le();
    this.timescale = this._io.readU4le();
    this.numFrames = this._io.readU4le();
    this.unused = this._io.readU4le();
    this.imageData = new Array(this.numFrames);
    for (var i = 0; i < this.numFrames; i++) {
      this.imageData[i] = new Blocks(this._io, this, this._root);
    }
  }

  var Blocks = Vp8Ivf.Blocks = (function() {
    function Blocks(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Blocks.prototype._read = function() {
      this.entries = new Block(this._io, this, this._root);
    }

    return Blocks;
  })();

  var Block = Vp8Ivf.Block = (function() {
    function Block(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Block.prototype._read = function() {
      this.lenFrame = this._io.readU4le();
      this.timestamp = this._io.readU8le();
      this.framedata = this._io.readBytes(this.lenFrame);
    }

    /**
     * size of the frame data
     */

    return Block;
  })();

  /**
   * Magic Number of IVF Files
   */

  /**
   * This should be 0
   */

  /**
   * Normally the header length is 32 byte
   */

  /**
   * Name of the codec e.g. 'VP80' for VP8
   */

  /**
   * The (initial) width of the video, every keyframe may change the resolution
   */

  /**
   * The (initial) height of the video, every keyframe may change the resolution
   */

  /**
   * the (framerate * timescale) e.g. for 30 fps -> 30000
   */

  /**
   * the timescale is a divider of the seconds (VPX is integer math only) mostly 1000
   */

  /**
   * the number of frames (if not a camera stream)
   */

  return Vp8Ivf;
})();
return Vp8Ivf;
}));