Manatee

How to convert WMA to MP3 on a Mac

· 6 min read

macOS has no built-in support for Windows Media Audio, so the Music app, QuickTime Player, and Quick Look all refuse WMA files. To convert them to MP3, use ffmpeg in Terminal (ffmpeg -i song.wma song.mp3) or drop the folder into Manatee and pick MP3; both decode standard, Pro, and Lossless WMA. The exception is WMA with DRM from an old online music store, which no converter on any platform will unlock.

Where WMA files come from

WMA was the default rip format for Windows Media Player for most of the 2000s. If you ripped CDs on a Windows PC in that era, inherited a relative’s music folder, or pulled audio off an old external drive, you probably have a lot of them. Digital voice recorders from the same period also wrote WMA, as did some lecture capture systems.

There are three flavors, and the tools below handle all three:

  • WMA Standard (often just “WMA”), lossy, the common one.
  • WMA Pro, lossy, higher quality, less common.
  • WMA Lossless, which is exactly what it says, so converting it to MP3 starts from a perfect source.

A WMA file may also arrive inside an .asf container, which is the same family. Both ffmpeg and Manatee accept .asf.

Why the Mac cannot open them

Apple’s media frameworks never included the Windows Media codecs, and the third-party components that once added them to QuickTime stopped working years ago. So the failure mode is consistent: Finder shows a generic document icon, Quick Look shows nothing useful, and QuickTime Player reports the file is not compatible. The file is not broken; your Mac simply does not have the decoder.

That leaves tools that bring their own decoder, which is where ffmpeg comes in.

Option 1: ffmpeg in Terminal

ffmpeg decodes all three WMA variants and encodes MP3 in a single step. If you have Homebrew, brew install ffmpeg installs it.

  1. Open Terminal (Applications, Utilities).
  2. Type cd with a trailing space, drag your WMA folder onto the window, and press Return.
  3. Convert one file:
ffmpeg -i "song.wma" -codec:a libmp3lame -b:a 256k "song.mp3"
  1. Convert every WMA in the folder:
for f in *.wma; do ffmpeg -i "$f" -codec:a libmp3lame -b:a 256k "${f%.wma}.mp3"; done
  1. For an album collection organized in subfolders, run it recursively:
find . -name "*.wma" -exec sh -c 'ffmpeg -i "$1" -codec:a libmp3lame -b:a 256k "${1%.wma}.mp3"' _ {} \;

The MP3s land next to the WMAs, so the folder structure (artist, album) is preserved. Once you have checked the results, you can search Finder for “wma” and delete the originals, or keep them.

Option 2: Manatee

If the command line is not for you, Manatee does the same job from a window, with ffmpeg bundled inside.

  1. Open Manatee and choose Convert.
  2. Drag the WMA files, or a whole folder of them, into the window. You can also drag onto the menu bar icon.
  3. Pick MP3 as the target.
  4. Each file becomes a job in the list with its own progress. The MP3s are written alongside the originals; the WMAs are untouched.

Manatee never uploads anything and has no account. It is free for 24 hours with every feature, then $9 once with every future update included.

What it does not do: it does not remove DRM (see below), does not edit audio, and does not retag. For fixing up artist and album names afterward, the Music app’s Get Info panel is the tool.

Tags: what survives

WMA stores tags in its own ASF metadata format. ffmpeg and Manatee translate the common fields (title, artist, album, track number, year, genre) into ID3 tags in the MP3. Cover art embedded in the WMA usually comes across too.

Two things to check on a sample file before converting hundreds:

  • Rips with no tags at all. Early Windows Media Player rips sometimes stored track names only in the file name. The MP3 will be untagged; the Music app can fill in tags from the file name when you import, or you can do it by hand.
  • Non-English characters. Older WMA tags in some encodings can come out garbled. If you see question marks where accented letters should be, retag in the Music app.

Bitrate for old rips

Most WMA rips from the 2000s were made at 64 to 128 kbps, because hard drives had no room for more. A 128 kbps WMA does not contain 320 kbps worth of detail, so encoding the MP3 at 320 kbps only makes a larger file.

A sensible rule: use an MP3 bitrate about double the WMA’s, capped at 320. That minimizes the extra loss from a lossy-to-lossy conversion without wasting space. For a 64 kbps WMA, 128 kbps MP3. For a 128 kbps WMA, 256 kbps MP3. For WMA Lossless, 320 kbps. To see the source bitrate, run ffmpeg -i song.wma on its own and read the Stream line.

If you still own the CDs, re-ripping them to a lossless format gives a far better result than converting a 64 kbps WMA ever can. Lossless vs lossy: what happens to audio when you convert it explains why.

The DRM wall

Music bought from online stores in the WMA era often came wrapped in Windows Media DRM. Those files need a license from the store, and most of those stores closed their license servers long ago, which means the files no longer play even on Windows.

Neither ffmpeg nor Manatee will convert a DRM-protected WMA, and Manatee does not attempt to crack protection of any sort. The error will look like a decode failure. The only legitimate route is the one that worked at the time: burn the tracks to an audio CD on a machine with a valid license, then rip the CD. If no licensed machine exists, the purchase is effectively gone.

To tell the difference between a DRM file and a damaged one, try ffmpeg -i song.wma alone. A DRM file reports its streams but refuses to decode; a damaged file reports a header or format error. For a damaged file, ffmpeg will often still convert the intact portion, and corrupted MP3 or M4A won’t play on Mac: how to repair it covers the general approach.

Questions

Can the Music app import WMA if I install something? Not anymore. The Windows version of iTunes once converted WMA on import; the Mac version never did, and the Music app does not either. Convert first, then import the MP3s.

I have WMV videos in the same folder. Same process? Yes, but with a video target. How to convert WMV to MP4 on a Mac covers it; Manatee accepts .wmv and offers MP4 and MOV.

Should I convert to M4A instead? If every device you use is reasonably modern, AAC in an M4A is a touch more efficient. MP3 is the safer bet for old car stereos and the widest compatibility, and both tools offer either.

A WMA from my voice recorder converts but the MP3 is only the first few seconds. The recorder probably lost power or was disconnected mid-recording, so the index at the end of the file is missing. Try ffmpeg with -err_detect ignore_err placed before -i; it will usually push through and convert everything up to the point where the recording stopped. Whatever was never written to the file cannot be recovered by any tool.