h5bp/html5-boilerplate — pull request #1078 by tomByrer (2012-05-01 08:00:30+00:00)
Title: + mp3 & WebM audio formats

https://developer.mozilla.org/En/Media_formats_supported_by_the_audio_and_video_elements
http://html5doctor.com/native-audio-in-the-browser/
http://transom.org/?p=26567

Silly IE9, liking only mp3 & wave. Refrained from adding wave format; usually .zipped & meant for downloading to be used by audio editors, very rarely used for live streaming, if ever.

WebM perhaps is uncommon as an audio format, but those encoding for WebM video might notice they can do audio also.