How is the resumable Youtube uploader working?

Question

Any idea how the youtube video uploader works? The interesting feature here is that you can resume a broken upload-process (e.g. when you close the browser or your internet connection is lost meanwhile). It seems that they do not use Java, Flash or some other native stuff. Perhaps any fancy HTML5 stuff? Or browser-specific methods?

Answer 1

I verified that youtube doesn't use Flash (my first guess) using flashblock. It appears that they are using the fancy new HTML5 javascript file api.

You can read about how this can be done (mozilla specific): https://hacks.mozilla.org/2011/04/resumeupload/

Or check out this neat library that helps you achieve resumable uploads: https://github.com/23/resumable.js