Standard Mpeg Encoder
The Standard Mpeg Encoder was a set of DirectShow filters for encoding video streams to the MPEG formats (1, 2, 4). It allowed the encoding of any stream that could be DirectShow decoded into an MPEG format, and used standard DirectShow output methods. I started the project around 2002 and maintained it till 2008, when I open sourced it down to start something else.
It was sold for about $700 for a license, and had a lot of sales over the period. I also developed DirectConvert, an end-user version, that sold for $20. It also made a lot of sales over this same time period. The two pieces of software financed my university education :-)
The full source code is open source and available here: DirectEncode on Github.