Streaming Media - December 2008/January 2009 - (Page 71)

Windows Media encoding run. If the encoding software turns out to be incompatible with the Tarari accelerator, the icon does not blink. Which leads us to the next question: Who’s in and who’s out? Compatible Programs According to LSI’s product brief, the “LSI Tarari Encoder Accelerator provides seamless acceleration for any WMV and VC-1 encoding applications based on the Microsoft Windows Media Format SDK—without the need for any special scripting or digital glue.” Obviously, this means that there are programs that won’t be accelerated. I checked the status of the most commonly used Windows encoding programs with the LSI representative and then consolidated the information in Table 1. As you can see, most of the prominent encoding tools work today or will work very soon. In addition, note that if you’re encoding using scripts that call Microsoft’s Professional, Enterprise, or even the older SDK 11 for WMV, the Tarari board will accelerate your rendering. The Adobe situation stems from the company using a MainConcept API rather than a Microsoft API for the Adobe Media Encoder. Barring any changes, it may not be possible to make the Tarari accelerators compatible with the Adobe Media Encoder. On the other hand, LSI has been compatible with previous versions of Sorenson Squeeze, and the company promised the necessary fixes very soon. Still, if you’re buying the software to use it with Sorenson Squeeze, you should first verify that LSI has completed the necessary work. Testing With coprocessor cards such as Tarari, your results will vary based on the encoding program you’re using, input and output resolution, and the encoding setting you’re using (1-pass or 2-pass encoding). When comparing your results to baseline, computeronly encoding, the speed and the number of cores in the test computer will also affect the results. To try to illustrate this, I ran different tests on the programs that I had available (Table 2). Let’s start with Canopus ProCoder, a relentlessly efficient encoding program on multicore systems such as my test bed HP xw8400. Here, I encoded five 1-minute SD files to 640x480 resolution at a data rate of 500Kbps (468 video/32 audio) and three 720p files to 1280x720p resolution at a combined data rate of 928Kbps (800 video/128 audio). I produced all files using 2-pass encoding since that’s my general practice. With the Tarari accelerator, it took 11:21 (min:sec) to produce the files; without the card, it took 45:46. On a percentage basis, this means that Tarari reduced encoding time by 75%. I compared the quality of the files produced with and without the card and found them visually identical, though the final size varied slightly. Something was different, though it wasn’t noticeable. I then rendered a single HD file to the same parameters in Rhozet Carbon Coder, using single-pass rather than 2-pass encoding. Encoding without the card took a glacial 20:30, while encoding with the card took 2:41—a time savings of more than 87%. I then reran the tests using 2-pass encoding to see if Tarari accelerated the first analysis pass. With and without the card, the analysis pass took about 2:20. This illustrates why single-pass encoding should produce higher-percentage speed increases than 2-pass. Essentially, the first pass is a “fixed cost” that remains the same whether the Tarari card is used or not, bringing down the percentage of time savings. However, the actual minutes saved will be about the same, which is probably the more important metric. Microsoft Encoding Tools Let’s move on to the Microsoft encoding tools: the venerable Windows Media Encoder and the more Table 2. Summary of Results Program ProCoder Carbon Coder Windows Media Encoder Windows Media Encoder Expression Encoder 2 Expression Encoder 2 Description Eight simultaneous files: five SD and three HD One HD file Three HD files in sequence Three HD files simultaneously Three HD files in sequence Three HD files simultaneously Without Tarari 45:46 20:30 30:17 11:11 21:41 10:28 With Tarari 11:21 2:41 11:19 6:28 5:49 6:50 Reduction in Encoding Time 75% 87% 63% 42% 73% 35% WWW.STREAMINGMEDIA.COM 71 http://WWW.STREAMINGMEDIA.COM

Table of Contents Feed for the Digital Edition of Streaming Media - December 2008/January 2009

Streaming Media - December 2008/January 2009 Table of Contents User-Generated Politics Netflix Needs a Business Model Technology and Business Trends by the Numbers Improving Video Color Quality What Makes for Compelling Video? Game On: Bringing the NHL to IPTV Give! The New Era of Corporate Communications New Video Frontiers: Taking It Beyond the PC The HD Showdown: Codec Vendors Battle It Out for Supreme Quality The Ultimate Guide to Creating Online Video Content That Works, Part 2 Planning for Webcasting Success: Considerations for Deploying an Enterprise Video Communications Platform All Mobile Devices Are Not the Same Datmedia Datpresenter LSI Tarari Encoder Accelerator LCPX-6140 Gomez Active Streaming XF Transcoding for Global Reach Executive Visions 2009 The Revolution Is Being Televised

Streaming Media - December 2008/January 2009

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