I attended a few more Post Production World sessions that I didn’t get a chance to mention yesterday. Ben Waggoner’s “Compression for DVD” session was especially interesting, and appealed to me as a guy who finds comfort in the certainty (more or less) of numbers. He didn’t get too deep into the hottest emerging issue for DVD authors—that would be HD-DVD and Blu-ray authoring—but I certainly learned a bunch of great tips for packing the most bits onto a 4.7GB disc while maintaining the highest possible level of quality.

The first basic, elemental issue that Waggoner covered is one that hits home for many do-it-all author/shooter/editor types—encoding DV25-originated content to MPEG-2. It’s simply a bad idea to go straight from one to the other, because of the incompatibility of their respective 4:1:1 and 4:2:0 color sampling schemes. (4×1 horizontal blocks and 2×2 square blocks don’t mesh that well, who knew?) The answer, pretty obvious: Use an intermediate codec of some sort; just don’t render back out to DV25 before moving onto authoring.

Waggoner also covered I-frame efficiency (chapter-marker support is key); options for packing more minutes onto discs (use Half D1 resolution, variable bit rate encoding, and/or a 704-pixel width); and appropriate bit rates for stereo and 5.1 audio. For those who need a bit of continual reassurance each time they approach an encoding project, he plugged a friend’s Bit Budget Spreadsheet. And finally, he revealed the results of his MPEG-2 encoder shootout: At both HD and SD resolutions, Waggoner found that Canopus’ ProCoder had a slight edge across a variety of tests.