We heard today about some MPEG-DASH experiments in Google Chrome. We think Google is behind this initiative because 1) there is a Youtube logo, 2) the data are stored on Google Cloud Storage and 3) it used the Media Source API which is developped by Google for a future use with HTML5 <video> (more on that below).

We have already talked about MPEG-DASH on this blog since we contributed to this specification. GPAC was used to do some experiments (both industrial and academic). It was the first tool to be updated to the final draft version, both on the generation side (MP4Box) and on the playback side (MP4Client and Osmo4). And we have also built and shared some test-sequences to show different aspects of the specification.

Fewer may know about Media Source API. It is an extension proposed by Google over the HTML5 <video> element. It aims to provide a media pipeline which can be controlled using scripts (e.g. Javascript). Today you are limited to play one URL per media. With Media Source you’ll be able to push your own data to the media decoder. This is a key feature for an implementation of MPEG-DASH within web-browsers. Media Source recently moved from a Google hosted page to a more official W3C HTML “Media Source” draft standard.

The Google hosted website contains some useful information. A interesting aspect is the use (and support) for the MPEG4-ISO Base Media File Format (widely known as .MP4). Until now Google only made advertisement around their own WebM container. A previous implemention of DASH within a Web-browser using WebM was done at the Klagenfurt University. The Media Source reference can be found here. The GPAC team is strongly commited to this standard and our implementation has been widely used (x264, Youtube, etc.) so we’re happy with these changes from Google. The MPDs you can test on the website have actually been generated by MP4Box.

For those interested in some testing, the implementation is quite promising although we have observed many crashes or stalls. You’ll need an experimental version of Chrome provided by Google called Canary. Go to the “chrome://flags” address and activate 1) the Media Source API and 2) the Multimedia Extensions. Reboot your browser.

Aside from the provided movie dataset and less interesting for the average reader, you can find some TS tests. The motivations are well explained. The content of these tests look pretty similar to the GPAC DASH Sequences and Apple “bipbop” tests. It shows one more time how academic researches and open-source developments can influence the biggest software companies.