How does youtube player work

Question

What i'm interested in mostly is video quality.

Do they convert each video file to many separate video files, or do they convert file on the fly when user is watching the video to preserve space? So basically how different video qualities are made.

Also, what video formats works with flash? Which one is the most commonly used?

What would i sacrifice if i would use HTML5 instead of flash? I saw youtube is switching to HTML5, do their player work in every browser, even IE7?

How hard would it be to make youtube flash or HTML5 player copy?

Thanks.

Answer 1

Every video uploaded is converted into a couple different MIME types. HTML5 allows you to easily add videos without needing your own custom flash player. You can also make your own player using normal elements found in every browser. Although HTML5 is not supported in all browsers, it's becoming more popular and will (hopefully) be implemented in all browsers soon. I'm not completely sure which video formats work with flash, but I can only assume that all do. I could make a replica of the html5 youtube player in a day.

MIME types - Mime types are essentially different file types. They are different files. Example, I have an mp3 file, I could convert it into a wav file and an ogg file and I would have three different MIME types. Read this for more info on Mime types