Video Compression Comparison has recently completed another in its ongoing series of video compression codec comparisons. Doom9’s primary focus is on backing up video DVDs, whether that means copying them to DVD-R, or further compressing them so that a full movie will fit on one or more CD-Rs.

Because of this focus, the primary concern is with overall video quality at a particular data rate or file size. Thus, the winners are implementations of MPEG4, which is an open standard. Since some standalone DVD players are now also supporting MPEG4, this makes sense.

However, this sort of evaluation should not necessarily be generalized to how particular codecs perform in streaming implementations. The conditions that face streaming–packet loss, network congestion, etc–aren’t present with a video file burned to a disc. Therefore, data that in a streamed video would have to be dedicated to transport information can be put to use to carry more video information with a non-streamed file.

I think that’s one reason why Real Video codecs tend to come out lower in the pack in these comparisons–it’s primarily a streaming codec, and in my experience performs very well in that regard. However, while I do recommend Real for streaming applications where simplicity is valued over other priorities like open standards, I would not recommend it as a good codec for archiving video or backing up DVDs.

The advantage to MPEG4 implementations is that videos encoded in this format can be transcoded fairly easily to be used in other applications. Real Video cannot.

This isn’t such a problem for Real when you are focused on streaming, since your streaming file should not be the one you archive — you should always archive the highest quality file you have so that you can transcode or re-encode to new, more advanced codecs as they become available.

As a real-world example, I’ve been working on making videos from this past August’s Community Wireless Summit available both for streaming and download. For the streamed videos, I’m using Real Video 9 streamed off a Real Helix server. The quality is decent on broadband, scales to lower bandwidths, and adapts smoothly to network conditions.

For the downloadable videos, I’ve used the Quicktime implementation of MPEG4, since this will give a nice quality file for those who want to keep a copy of the video. That file can easily be played on MPEG4 capable DVD players, or transcoded to VCD or even DVD.