The previous post requires some corrections.
According to the license.txt file distributed with version 2 of the SDK the filter DLLs are listed as "Developer Tools" --not "Licensed Binaries". You are free to recompilesamples with source included, whether you add modifications or not. Your recompiled versions then fall under the Sample Source category, meaning that (for version 2) you may redistribute.
The mux/demux tools do not include source,and they cannot be redistributed. The reason for the distinction is that these do not use the Media SDK and are intended only for development support. They are sample binaries only, and not developed/tested to production standards.
As I mentioned before, this applies only to version 2. For version 3 even samples with source are not redistributable until the product hits Gold.
The license documentation could be clearer. We are hoping to address thisin future releases.
Please let us know if you have any further questions on this issue.