WMA, ASF and the Windows Media Player years
Windows Media Audio arrived in 1999 as Microsoft’s answer to MP3, at a moment when MP3 encoding still carried licence fees and Microsoft wanted the desktop audio stack to be its own. For most of the following decade it was the default: insert a CD, open Windows Media Player, click rip, and what landed on the drive was a folder of .wma files whether or not you had an opinion about it.
The files are not really WMA the format so much as WMA the codec inside ASF, the Advanced Systems Format container Microsoft designed for streaming. The same container holds WMV video, which is why the two formats behave so similarly and why both faded at the same time. ASF was built for an internet where audio arrived over a dial-up link and needed to survive packet loss, and its design shows that ancestry.
What happened next is the reason this page exists. Microsoft lost the portable player argument, the iPod ignored WMA entirely, phones followed the iPod, and the format quietly stopped being supported anywhere outside Windows. The files did not go away. They sit on external drives, on inherited laptops, on backup DVDs, and on the memory of a digital dictation machine somebody found in a drawer.
The DRM-protected variant that will not decode
Before anything else, check what kind of WMA you have, because one variety cannot be converted by this or any other tool.
Windows Media DRM wrapped purchased and subscription audio in encryption tied to a licence file on the machine that downloaded it. Services built on it, including the various music subscriptions of the mid-2000s and a large amount of audiobook and library-lending content, issued files that look like ordinary .wma and are not. The licence servers for most of those services have been switched off for years.
FFmpeg has no way to decrypt that content, so the decode produces nothing and the page reports its generic failure message: Something went wrong while processing your file. Please check the file is valid and try again. There is no workaround here, and any site promising one is either recording the audio as it plays or lying. If the file came from a shop or a subscription rather than from your own CDs, that is the likely explanation.
wmav2, WMA Pro, WMA Lossless and WMA Voice
“WMA” covers at least four different codecs that share one extension. The original WMA and the far more common WMA 2, which FFmpeg calls wmav2, are the standard lossy codecs behind almost every CD rip. WMA Pro added multichannel and higher sample rates. WMA Lossless does what its name says. WMA Voice is a low-bitrate speech codec used by dictation hardware and Windows Sound Recorder.
The converter does not ask you which you have. FFmpeg’s own decoders handle the family, and the module simply names the virtual input file input.wma so the ASF demuxer is chosen, then lets the decoder identify what it finds. Practically, the only reason to care is that a WMA Lossless file deserves the top bitrate rung and a WMA Voice recording does not.
Rescuing a CD library ripped in 2004
The job that brings people here is rarely a single track. It is a folder structure of Artist and Album directories, ripped over several years by somebody who has since bought a phone, and now unreadable by every device in the house. This page still takes one file per run, so that archive is an evening of dropping tracks in rather than one click, which is exactly why the next two habits are worth adopting.
Two habits make that less painful. Convert the albums you actually listen to rather than the whole archive, because the source rips were often at a low bitrate and a lot of that library is not worth the afternoon. And keep the .wma originals on the old drive until you have checked the results, since a rip with a damaged sector converts happily and hides the damage inside a new file.
Bitrate choices for a source that was already lossy
Windows Media Player’s default rip quality was modest by modern standards, so most WMA files you meet were already compressed fairly hard. Feeding that into an MP3 encoder is a second lossy pass, and the second encoder cannot see what the first one removed.
192 kbps (recommended) is the default here and is the honest choice for a normal rip: enough headroom that the re-encode does not add anything you can hear, without inflating the file to describe detail that is not present. 320 kbps (highest quality) is worth taking from WMA Lossless or from a rip you know was made at a high setting. 128 kbps (smaller file) suits dictation and voice recordings, which is what a lot of surviving WMA actually is. For a genuinely lossless source, the same reasoning as FLAC to MP3 applies.
Converting one WMA file
- Drop the
.wmafile onto the box above, or click Choose a file to browse for it. - Choose an Audio quality, leaving it on 192 kbps (recommended) unless you know the source was lossless or spoken word.
- Click Convert WMA to MP3 and watch the progress bar. A Cancel button sits below it while the run is in progress.
- Download the MP3, then click Process another before dropping the next file, since new files are ignored until the previous result is cleared.
What the conversion cannot bring back
Converting fixes playability and nothing else. A rip made at 64 kbps in 2003 will sound exactly as thin afterwards, because the missing high frequencies were discarded at rip time and no format change recovers them. If you still own the CDs, re-ripping them to a modern lossless format will always beat converting the old files.
Embedded artwork is dropped as well: FFmpeg exposes it as a video stream and the converter passes -vn to strip everything that is not audio. For old phone recordings that came off a handset rather than a PC, AMR to MP3 is the matching page, and Audio Converter handles mixed input formats from a single screen.