Convert WMA to ALAC — Free Online Tool
Convert WMA files to ALAC (Apple Lossless Audio Codec) entirely in your browser — no uploads required. This tool decodes the lossy WMA audio stream and re-encodes it into a lossless ALAC file stored in an MPEG-4 container (.m4a), making it fully compatible with iTunes, Apple Music, and iOS devices.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your WMA file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
WMA files store audio using Microsoft's lossy WMSv2 codec (or occasionally WMSv1), which discards audio data during compression to reduce file size. During this conversion, FFmpeg fully decodes the WMA audio back to uncompressed PCM in memory, then re-encodes it using Apple's ALAC codec into an .m4a container. Because the original WMA source is lossy, the resulting ALAC file will be lossless — but only lossless relative to the WMA source, not the original recording. Any data discarded when the WMA was first encoded cannot be recovered. The ALAC output will typically be noticeably larger than the source WMA file, as lossless compression stores far more audio detail than a lossy 128k bitrate WMA.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — in this browser tool, that is FFmpeg compiled to WebAssembly (ffmpeg.wasm), which runs the same conversion logic as the desktop version entirely within your browser tab. |
-i input.wma
|
Specifies the input file in WMA format. FFmpeg automatically detects the ASF container and the WMAv2 (or WMAv1) audio codec inside it, then fully decodes the lossy audio stream to uncompressed PCM before re-encoding begins. |
-c:a alac
|
Sets the audio codec to ALAC (Apple Lossless Audio Codec) for the output. This instructs FFmpeg to encode the decoded PCM audio using Apple's lossless compression algorithm, which stores every audio sample without further quality loss. |
-c:a alac
|
This flag appears twice in the resolved command, which is redundant but harmless — FFmpeg simply applies the last valid value for each stream specifier. The effective result is the same: the audio output is encoded as ALAC. When running the command manually, a single -c:a alac is sufficient. |
output.m4a
|
Defines the output filename with the .m4a extension, which tells FFmpeg to wrap the ALAC-encoded audio in an MPEG-4 container. The .m4a extension is the correct and expected container for ALAC files and ensures native compatibility with Apple Music, iTunes, and all Apple devices. |
Common Use Cases
- Migrating a legacy Windows Media Player music library to Apple Music or iTunes on Mac without accepting another round of lossy re-encoding
- Preserving purchased or archived WMA files in a format compatible with iPhone and iPad, which do not natively support WMA playback
- Preparing WMA audio files for use in Final Cut Pro or Logic Pro X, which work natively with ALAC inside .m4a containers
- Archiving WMA broadcast recordings or radio captures in a lossless container to prevent further quality degradation from future re-encoding
- Converting WMA audiobooks or spoken-word recordings to ALAC so they can be synced to Apple devices via the Books or Music app
- Standardizing a mixed audio library of WMA and other lossy formats into a single lossless ALAC archive for long-term storage
Frequently Asked Questions
No — ALAC is lossless, but it cannot recover audio data that was discarded when the original WMA file was created. The ALAC output will be a perfect, bit-for-bit lossless copy of whatever audio survived the original WMA encoding. If your WMA was encoded at 128k, the ALAC file will sound identical to that 128k WMA — just stored without any additional compression artifacts. The benefit is that no further quality loss will occur in any subsequent conversion from the ALAC file.
WMA at 128k bitrate achieves its small file size by permanently discarding audio data the encoder deems inaudible. ALAC, being lossless, must store every audio sample it receives — even if those samples came from a lossy source. A typical 4-minute WMA file at 128k might be around 4MB, while the same audio as ALAC could be 25–40MB or more. This size increase is expected and does not indicate a problem with the conversion.
In most cases yes — FFmpeg maps standard metadata tags from the WMA ASF container to the MPEG-4 container used by ALAC. Tags like artist, album, title, and track number typically transfer correctly. However, WMA DRM-protected files (using Microsoft's PlayReady or older DRM schemes) cannot be converted at all, as the encryption prevents FFmpeg from decoding the audio stream.
Yes. Apple developed ALAC and it is natively supported across all Apple platforms including iOS, iPadOS, macOS, tvOS, and watchOS. The .m4a files produced by this conversion will play in the Music app, be recognized by iTunes, and can be synced directly to any iPhone or iPad without transcoding. Android support for ALAC varies by device and app, so ALAC is best suited for Apple ecosystems.
The FFmpeg command shown on this page handles a single file, but you can batch process an entire folder on the command line using a shell loop. On macOS or Linux, run: for f in *.wma; do ffmpeg -i "$f" -c:a alac "${f%.wma}.m4a"; done. On Windows Command Prompt, use: for %f in (*.wma) do ffmpeg -i "%f" -c:a alac "%~nf.m4a". This will convert every WMA file in the current directory to ALAC, which is especially useful for large library migrations beyond the browser tool's 1GB limit.
No. WMA files with Microsoft DRM (Digital Rights Management) protection are encrypted, and FFmpeg cannot decode them — you will receive an error when attempting conversion. DRM-protected WMA files were commonly sold through services like MSN Music and PlaysForSure stores in the mid-2000s. If your WMA file plays normally in Windows Media Player but refuses to convert, DRM protection is the most likely cause. Only unprotected WMA files can be converted.
Technical Notes
WMA audio comes in two main codec variants: WMAv2 (the default and most common) and the older WMAv1. Both are fully decoded by FFmpeg before ALAC encoding begins. ALAC stores audio in a predictive lossless compression scheme inside an MPEG-4 (.m4a) container and supports all standard bit depths and sample rates, including 16-bit/44.1kHz CD quality and higher resolutions up to 32-bit/384kHz. Because WMA is typically distributed at 16-bit/44.1kHz or 16-bit/48kHz, the ALAC output will mirror whatever sample rate and bit depth the source WMA used. No quality controls are exposed for ALAC since it is lossless — there is no bitrate to set. One known limitation: WMA does not support multiple audio tracks or embedded subtitles, so there is nothing to lose on that front. Chapter support is added by the ALAC/M4A container if chapter metadata is present in the source, though WMA files rarely carry chapter data. Metadata tag compatibility is generally high, but custom or non-standard WMA tags may not have direct equivalents in the MPEG-4 tag schema and could be dropped.