By default, it uses the HTML5 File API to chunk a file in the client and upload the chunks to Ooyala's servers. This requires a browser that supports the File APIs. Supported browsers are Firefox 15+, Chrome 22+, Safari 6+, and IE with the ChromeFrame plugin. This is the recommended approach, particularly for large files, since a failed request only involves retrying that chunk rather than the entire file. It also boosts upload speed since multiple chunks can be uploaded in parallel.For older browsers that do not support the File API, the library uses a Flash swf from the swfUpload library to upload the file in a single chunk. The library supports browsers with Flash version 9 or greater.