Streaming Media - August/September 2008 - (Page 29)

• Bitrate: 48Kbps—This matches the data rate of the FLV source. Also, this is the minimum bitrate for WMA VBR. I always try to use at least 48Kbps for WMA progressive for that reason; it’s a massive quality jump from 32Kbps CBR for typical content. • Sample Rate: 44.1 kHz—This is the same as the source. Also, 44.1 is the native audio rendering mode for Silverlight, so it offers the same quality and better performance compared to 48 kHz. • Bits per Sample: 16—This is the only option for WMA, and it also matches the source. • Channels: Stereo—WMA VBR audio requires stereo. I’d use mono if I needed to do 32Kbps, since stereo separation isn’t important to the experience here. Like other modern codecs, WMA in stereo mode functions essentially as a mono codec when encoding mono sources. • Audio peak bitrate: 96Kbps—Again, the total peak comes out as 1Mbps. The audio isn’t that difficult or variable, so a higher bitrate likely wouldn’t sound any different. • Audio peak buffer size: 1.5Kbps—The default is almost always fine. ADVANCED CODEC SETTINGS • Video Complexity: Best (5)—It’s a short clip at a reasonable frame size. The default Complexity (3) probably would have been just as good, but the encode only takes about 12 minutes at 5 (Figure 6), so I didn’t bother doing anything less than the max (I love my new eight-core workstation). Even on a slower machine, the encoding time would still be less than I spent setting up all my markers. PERCEPTUAL OPTIMIZATIONS • Adaptive Dead Zone: Conservative—This is the default setting. It softens out edges and flatter areas that might otherwise ring or get too blocky, but not by too much. I tried both Off and Aggressive with this source, and Conservative definitely looked the best, as usual. • Dquant: I-Frames Only—Differential Quantization is a codec mode that applies less aggressive compression in smoother parts of the image. There aren’t many keyframes/I-frames (mainly the few dozen we set manually, and perhaps a few more natural ones), but WWW.STREAMINGMEDIA.COM 29 http://movenetworks.com http://movenetworks.com http://WWW.STREAMINGMEDIA.COM

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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