Convert WMA to MP3
WMA is Microsoft's audio codec inside an ASF container - a Windows-era answer to MP3 and AAC that never gained playback support outside Windows Media Player and a handful of desktop players. Its four variants (WMA 1, WMA 2, WMA Pro, WMA Voice) and one lossless variant (WMA Lossless) all decode through Wave's wasm engine. The MP3 output plays on every device that plays sound - which WMA has never done. See Audio codecs explained for where WMA sits in the current audio codec landscape.
What actually changes
WMA files sit inside ASF (Advanced Systems Format) containers and can hold one of five distinct audio codecs. WMA 1 (1999) was the original Microsoft challenger to MP3 - competitive at low bitrates but rare in the wild today. WMA 2 (2001) is the workhorse of the WMA era, with stereo joint-coding improvements and the "WMA 9" and "WMA 9.2" brand versions that dominated Windows Media Player music libraries through the 2000s. WMA Pro (2004) added support for 5.1 surround at up to 24-bit / 96 kHz. WMA Voice (2003) is a low-bitrate speech codec used for dictation software. WMA Lossless is bit-exact reversible - equivalent to FLAC or Apple Lossless. Wave decodes all five through the ffmpeg-wasm engine.
The re-encode to MP3 is a straightforward decode-and-encode pass. Wave hands PCM samples from the WMA decoder to libmp3lame at 192 kbps VBR (LAME -q:a 2), which is transparent for typical WMA sources - most encoded at 128 or 192 kbps in the first place, so the MP3 output preserves everything they carried. WMA Pro at 5.1 downmixes to stereo before the MP3 encode using the standard SMPTE fold-down coefficients. WMA Lossless is handled the same way FLAC is: bit-exact decode to PCM, then LAME encode.
The most common reason to convert WMA to MP3 is compatibility. Windows Media Player wrote WMA as its default audio format from 2001 through the mid-2010s, and every Windows-attached music library from that era carries a lot of it. But Apple's iOS has never natively decoded WMA (macOS didn't either until Music replaced iTunes), Android's built-in support is inconsistent, and modern car head units almost universally drop WMA support. MP3 plays literally everywhere that plays sound.
DRM caveat: a small share of WMA files - mostly music purchased through Windows-Media-based online stores between 2003 and 2009 (Napster subscription, PlaysForSure content, some Zune Marketplace content) - carries Windows Media DRM. Wave cannot decrypt it. The ASF header carries a content_encryption_object flag that Wave detects during inspect and reports clearly. Ordinary WMA files - ripped CDs, DVR-captured audio, dictation exports - are unencrypted and convert normally.
Three steps.
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Step 1
Drop the .wma file onto the card.
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Step 2
Wave inspects the audio and confirms Decode-and-re-encode.
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Step 3
Convert. Save the MP3.
Answers, specifically.
Windows Media DRM-protected WMA files?
Wave cannot decrypt Windows Media DRM. If your WMA file was purchased from a Windows-Media-based store between 2003 and 2009, it likely carries DRM. Ripped CDs and other user-created WMA files are unencrypted and convert normally.
WMA Lossless - is the MP3 also lossless?
No - MP3 is a lossy format. But at 192 kbps VBR through LAME, the output is transparent for consumer playback. If you want a lossless target, keep the WMA Lossless source or convert to FLAC through a desktop tool.
WMA Pro 5.1 surround?
Downmixed to stereo before the MP3 encode. Wave uses the standard SMPTE fold coefficients since WMA Pro doesn't carry explicit Dolby downmix metadata.
WMA Voice for dictation recordings?
Yes. WMA Voice is a narrow-band speech codec (typically 8-16 kbps mono at 8 or 16 kHz sample rate). The MP3 preserves every audible sample but stays bandwidth-limited - the source, not the target, sets the ceiling.
Do WMA tags carry over?
Basic tags (title, artist, album, year) transfer to the MP3's ID3v2 frame. Album art in the WMA doesn't transfer through the current pipeline.
Windows Media Player 12 recordings?
Those write WMA 9.2 (a late refinement of WMA 2) or optionally WMA Pro. Wave decodes both.
What about .asf audio-only files?
Same handling - ASF is the container spec, and audio-only ASF files are just WMA files with a different extension. Wave treats .wma and audio-only .asf identically.