Streaming Media - August/September 2008 - (Page 26)

tutorial High-Touch Encoding With Microsoft Expression Encoder 2 A couple of months ago, I was chosen as a member of the inaugural Streaming Media All-Star team. There was a fun video montage presenting images of each of us on baseball cards, with voice over by Colorado Avalanche announcer Alan Roach. Good stuff, but the compression wasn’t quite up to my standards for this rare intersection of compression obsession and personal vanity. So I asked if I could take my own whack at it. This article is a detailed walkthrough of that process, as an example of what is sometimes called “high-touch” compression. This is the opposite of the high-volume automated encoding that a site such as YouTube does, and it is much more like the labor-intensive, quality-critical workflow that gets used for A-list DVD and Blu-ray titles. While not appropriate for most compression projects, for clips that will be seen widely, it can pay off. If something is going to be seen tens of thousands of times, even a slight improvement in quality can make a difference in communicating its message, and a 10% savings in bitrate can pay off in total bandwidth costs. Specifically, this article is going to show off some of the new encoding features of Microsoft’s new Expression Encoder 2 product for high-quality compression, authoring with Silverlight skins, and publishing to the Silverlight Streaming service. By Ben Waggoner Figure 1. An interlaced frame from the original encode The Source The most labor-intensive encoding projects are usually challenging because of source issues, not codec tweaking. This was no exception to that rule. The first thing I noticed viewing the original clip was that the background graphics and a few of the animations were interlaced. While a normal deinterlacing filter would have fixed that problem, that can induce additional softness as seen below. The heavyweight motion-adaptive deinterlacers available for tools such as AVISynth can be finicky to configure and extremely slow. And in the end, nothing beats getting the source fixed in the first place. Compression is the art of getting output as close to the original as possible with the available bits; higher-quality sources can provide a much bigger improvement than anything in the codec. I contacted the post house, and they fixed the background interlacing (it was just a matter of properly flagging the stock footage source as interlaced in After Effects, a common error with stock footage provided in the PNG or animation codecs) and re-rendered it for me as a lossless RGB PNG-codec QuickTime .mov file (PNG is easier to edit and generally produces smaller files than the old default “animation” codec). However, there were two shots that snuck through where one layer was still interlaced. I didn’t want to wait for another disc, so I dove into After Effects (all difficult preprocessing jobs seem to wind up in After Effects). For the interlaced frames (Figure 1), I used the “Reduce Interlace Filter” with a softness of one to blend the two fields together. Figure 2 (far left). Traditional deinterlace methods distorted the text on the cards. Figure 3 (near left). I used a five-frame cross-dissolve from the original progressive frames to the first interlaced frame to hide the slight loss of focus. 26 STREAMING MEDIA August/September 2008

Table of Contents Feed for the Digital Edition of Streaming Media - August/September 2008

Streaming Media - August/September 2008 Table of Contents No Doubt - Editor's Note Mo’ Videos, Mo’ Money: Solving the Problem of Network Cost Why Good Design Matters More Than Ever: Just. Press. Play. Technology and Business Trends by the Numbers High-Touch Encoding With Microsoft Expression Encoder 2 The State of the Content Delivery Market, 2008 Get a Life: New Tools Put Lifecasting Within Anyone’s Reach So Many Codecs, So Little Time: Comparing H.264 Files Using Codecs From Apple, Dicas, and MainConcept Writing an RFP for Maximum ROI: Things to Consider and Questions to Ask When Writing a Request for Proposal for a Corporate Webcasting System The Patent Wars Producing Screencams in Camtasia Studio Analyze That Using Video to Communicate Change for Business Success Intellectuals’ Property Rights

Streaming Media - August/September 2008

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