WMV and M4A explained
WMV is Microsoft's Windows Media video container, tied to Windows Media Player and rarely supported elsewhere.
M4A is an MP4 container holding only audio — usually AAC, sometimes Apple Lossless. The extension exists mainly so players know not to look for a video track.
- Where WMV files come from
- Old Windows recordings, corporate training videos and PowerPoint exports.
- Where M4A is used
- iTunes purchases, Apple Music downloads, voice memos and audiobooks.