The video half of the Windows Media family has aged just as awkwardly as the audio half. WMV and ASF files — old camcorder transfers, recorded webinars, burned lecture discs, family videos converted on a Windows XP machine — often won't open on a Mac or a phone at all.
When it's the sound you care about, this tool reads the audio stream out of the video and writes it as an MP3. AVI, MP4, MOV and MKV work here too, so a mixed folder of old recordings can go through in one pass.
Old recordings, salvaged
WMV was everywhere in the 2000s: Windows Movie Maker exported it, camcorder software transcoded to it, and corporate training videos shipped in it. The audio inside is usually Windows Media Audio at a modest bitrate, so 128 to 192 kbps is the right target — high enough to lose nothing, low enough to keep hours of recordings manageable.
For interviews, lectures and family recordings where speech is the whole point, 96 kbps halves the size again with no meaningful loss. If the recording is precious and you plan to clean it up in an editor, take it to WAV instead and avoid the lossy step entirely.