Microsoft Expression Encoder

Microsoft Silverlight is like the proverbial elephant; your impression depends upon where you touch it. In this article, I’ll touch it at the Expression Encoder, which is the encoding component of Expression Studio. Specifically, this article describes how to produce a Silverlight-compatible “media experience” with Expression Encoder, then upload it to the Silverlight Streaming Server, a streaming service offered by Microsoft, and to your own website. I will not discuss live video encoding, just on-demand.

From my perspective, Silverlight poses two main questions. The first question is whether to adopt Silverlight as a design and development architecture, particularly over Flash, and I’m not going there. The other question has a very easy answer: If you’re already producing Windows Media files, should you switch to Silverlight.

There are some absolute bars to Silverlight. It currently doesn’t perform multicasting as robustly as Windows Media, doesn’t offer server-side playlists, or multiple bitrate files; nor does it support the Windows Media 9 screen capture codec. In addition, Silverlight uses the same audio and video codecs as the current Windows Media Encoder, so you shouldn’t expect any increase in audio/visual quality.

So, why bother with Silverlight? For casual Windows Media producers, Silverlight lets you easily create a custom player for your video, which integrates more neatly into your web pages. It also allows Macintosh viewers to more easily play Windows Media video files, and should soon extend to Linux.

Even if you don’t make the switch to Silverlight, there are several valid reasons for Windows Media producers to consider Expression Encoder. For example, Expression Encoder can import QuickTime files, which is great if you’re producing in Compressor, After Effects, or Premiere Pro on the Mac. The Expression Encoder can batch encode multiple files, and is compatible with compression acceleration coprocessors from Tarari.

As we’ll see, the A/B comparison tool for assessing compressed quality is very robust, and the Expression Encoder has deinterlacing that actually works. Overall, it’s a lot more straightforward than the Windows Media Encoder, which is dowdy and has a frustratingly roundabout workflow.

But as we mentioned, the Expression Encoder does not produce multiple bitrate files. Even more surprising, it doesn’t support the advanced encoding options made available in the Windows Media Format SDK 11. Sure, the Expression Encoder supports command line encoding that implements those options, and will respond to registry key changes invoked via the WMV9 PowerToy discussed here ( and available here ( However, given that this is the first major encoding tool release after the SDK 11 release, I would have expected Microsoft to drink their own Kool-Aid and support the advanced parameters directly.

About Jan Ozer

I help companies train new technical hires in streaming media-related positions; I also help companies optimize their codec selections and encoding stacks, and evaluate new encoders and codecs.

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