How to detect audio in DVR-MS files?

Just yesterday I was working on the audio detection in dvr-ms files in one software. Seeing it as a proprietary format, I didn't expect much information on dvr-ms from the ASF specification or from MSDN. Some open source projects come to rescue, and the key GUID has been discovered.

Here's how I'm doing it:

When parsing ASF_Binary_Media, if the Major Media Type is 31178c9d-03e1-4528-b5823df9db22f503, and the Format Type is 05589f81-c356-11ce-bf0100aa0055595a or c4c4c4d1-0049-4e2b-98fb9537f6ce516d, then I can expect the Format Data to be WAVEFORMATEX, padded up to Format Data Size.