Working with Binary Data using Typed Arrays

With HTML5 comes many APIs that push the envelope on user experiences involving media and real-time communications. These features often rely on binary file formats, like MP3 audio, PNG images, or MP4 video. The use of binary file formats is important to these features to reduce bandwidth requirements, deliver expected performance, and interoperate with existing file formats. But until recently, Web developers haven’t had direct access to the contents of these binary files or any other custom binary files.
This post explores how Web developers can break through the binary barrier using the JavaScript Typed Arrays API, and explore its use in the Binary File Inspector Test Drive demo.
Typed Arrays, available in IE10 Platform Preview 4, enable Web applications to use a broad range of binary file formats and directly manipulate the binary contents of files already supported by the browser. Support for Typed Arrays has been added throughout IE10: in JavaScript, in XMLHttpRequest, in the File API, and in the Stream API.

Binary File Inspector

The Binary File Inspector test drive demo highlights some of the new capabilities offered by this combination of new features. You can see the ID3 headers for music files, get a sense of the raw bytes in video files, and also see how additional file formats, like the PCX image file format, can be supported in the browser with the use of JavaScript and Canvas.

In the example above, an .mp4 video is rendered using a