Daily Motion, OLPC and Theora

A while back it was announced that Daily Motion, an online video site, had opened an OLPC channel for sharing videos encoded using Theora for playback on OLPC's.

The channel, http://olpc.dailymotion.com, contains theora videos aimed at the OLPC audience. What's nice is that the videos playback in Firefox 3.1 using the native Theora support and don't require a plugin, for example this video.

Looking at the Daily Motion page it seems they use the <object> element to playback the Ogg Theora file, which uses the internal decoder and player user interface. This is a nice result from the adding of support for direct loading of Ogg files that Robert worked on.

Categories: firefox, theora, video

liboggplay playback performance

I made a tweak to tinyvid.tv yesterday to transcode youtube high definition videos if the HD version is available. This results in bigger videos and therefore stresses the performance of the video implementation in Firefox.

I'm not tweaking any parameters when transcoding so it's possible that I could produce a Theora file with better playback characteristics. In particular I don't have the bandwidth to stream a file of this size. Instead I have to wait until a large portion is downloaded before playing it back. But even then playback performance is terrible.

With the file fully buffered on my dual core multi-gigabyte, multi-gigahertz laptop the sound stutters and the playback is slow. Not a great experience.

I tried playback of the ogg file with the example player from liboggplay. The playback performance is exactly the same as within Firefox. No surprise there since I use liboggplay in the implementation.

It's not a limitation with libtheora as the playback using libtheora's example player is very good. Low CPU usage, full framerate, great sound. So it looks to me like it's either a liboggplay issue, or an issue with the way I'm using liboggplay. I've raised a trac ticket with the liboggplay developers to see if they can offer any advice.

I've also raised bug 474540 in the Mozilla bugtracking system to track the fix to apply for Firefox.

Non-HD videos play fine for me, it's when they get to about 720p that things fall apart. The fact that libtheora plays these well makes me confident that we can get the performance for these files much much better.

Categories: firefox, video, theora

Open Media Stack Video Specification

Rob Glidden posts that a draft of the open media stack video specification is now available for comment. The specification defines a video decoder and associated bitstream syntax for decoding and playing video streams. From the specification:

The OMS video compression specification is based on legacy royalty-free technology and avoids the recently patented technology.

While this approach sacrifices the performance gains of recently patented techniques, the OMS video compression specification includes innovations of its own that at least partially compensate for these losses.

In addition, the OMS video compression specification takes advantage of contemporary semiconductor technology both to avoid the patented technology that was directed toward specific implementations, and to allow more sophisticated processing.

Where appropriate, patenting the innovations associated with the OMS video compression specification will provide a defensive portfolio of IPR to help maintain OMS as a mainstream royalty-free compression solution.

The specification can be downloaded here.

Categories: video