Convert WMA to WEBA — Free Online Tool
Convert WMA files to WEBA format, transcoding Windows Media Audio (WMV2/WMV1) into an Opus-encoded WebM audio container optimized for modern web delivery. WEBA with Opus codec offers superior compression efficiency compared to WMA, making it ideal for web applications that need smaller file sizes without sacrificing perceptible audio quality.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your WMA file here
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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 encoded with Microsoft's proprietary WMV2 or WMV1 codec inside an ASF (Advanced Systems Format) container. During this conversion, FFmpeg fully decodes the WMA audio stream into raw PCM audio, then re-encodes it using the libopus encoder and packages the result into a WebM container with a .weba extension. Because WMA and Opus use fundamentally different encoding algorithms — WMA relies on modified discrete cosine transform (MDCT) techniques tuned for Microsoft's ecosystem, while Opus is a hybrid codec combining SILK and CELT — full re-encoding is unavoidable. This means audio quality depends on both the original WMA bitrate and the target Opus bitrate. Since both formats are lossy, this is a lossy-to-lossy transcode, and some generation loss is inherent, though Opus is generally more efficient than WMA at the same bitrate.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg multimedia processing tool. In this browser-based tool, FFmpeg runs as a WebAssembly (wasm) binary entirely within your browser — no data is sent to any server. When running locally on your desktop, this calls your system's installed FFmpeg binary. |
-i input.wma
|
Specifies the input file — a WMA file encoded with Microsoft's WMV2 or WMV1 audio codec inside an ASF container. FFmpeg will fully decode the proprietary WMA audio stream into raw PCM before re-encoding. |
-c:a libopus
|
Sets the audio codec to libopus, the open-source Opus encoder. Opus replaces the Microsoft WMV2 codec and uses a hybrid SILK/CELT encoding approach that delivers better compression efficiency than WMA, particularly at bitrates of 128k and below. |
-b:a 128k
|
Sets the target Opus audio bitrate to 128 kilobits per second, matching the most common WMA default bitrate. At this bitrate, Opus typically produces audio quality comparable to or slightly better than WMA at the same bitrate due to its more modern encoding algorithm. |
-vn
|
Disables any video stream in the output. This is required for WEBA, which is an audio-only WebM container — it also prevents any embedded album art or image attachments in the WMA file from being incorrectly treated as a video stream and causing errors. |
output.weba
|
The output filename with the .weba extension, which signals to FFmpeg to use the WebM container format in audio-only mode. The .weba extension is the standard designation for audio-only WebM files and is recognized by HTML5 audio elements in modern browsers. |
Common Use Cases
- Preparing archived WMA music libraries or podcast recordings for use in browser-based audio players that natively support WebM/Opus but not Microsoft's proprietary WMA format
- Converting WMA audio assets downloaded from older Windows Media Player libraries or Zune stores into a web-compatible format for embedding in HTML5 audio elements
- Reducing file sizes for WMA spoken-word content (audiobooks, lectures) before hosting on a web server, since Opus maintains intelligibility at lower bitrates than WMA
- Transcoding WMA audio from Windows-era media archives into WEBA for use in WebRTC or web-based communication tools that leverage the Opus codec natively
- Migrating WMA files from legacy Windows Media Center recordings into a format compatible with modern open-source media players and web platforms without relying on Microsoft codecs
- Converting WMA audio tracks extracted from older Windows Movie Maker projects into WEBA for use in browser-based video editing or streaming applications
Frequently Asked Questions
Yes, some quality loss is unavoidable because this is a lossy-to-lossy transcode. Your WMA file was already compressed using Microsoft's WMV2 codec, and re-encoding it with Opus introduces a second generation of compression artifacts. That said, Opus is a highly efficient modern codec — at 128k (the default), it typically sounds comparable to or better than WMA at the same bitrate. If your original WMA was encoded at a higher bitrate like 192k or 256k, consider setting a matching or higher Opus bitrate to minimize perceptible degradation.
WEBA with Opus audio has excellent support in Chrome, Firefox, and Edge, but Safari on macOS and iOS has historically had limited or no native support for the WebM container. If you need broad cross-browser compatibility including Safari, consider converting your WMA to OGG (also using Opus or Vorbis) or MP3 instead. For purely web-application or server-side use cases, WEBA/Opus is a strong choice where codec support can be controlled.
WMA files commonly store metadata such as artist, album, title, and track number using ASF metadata attributes. FFmpeg will attempt to map these to equivalent WebM/Matroska metadata tags during the conversion. However, because WMA's metadata schema (including Microsoft-specific fields like WM/AlbumArtist or WM/BeatsPerMinute) doesn't map perfectly to WebM tags, some fields may be dropped or renamed. DRM-protected WMA files will fail to convert entirely, as FFmpeg cannot decrypt protected content.
The -vn flag explicitly tells FFmpeg to exclude any video streams from the output. Even though WMA is an audio-only format, FFmpeg's container detection can sometimes identify embedded album art or other image attachments as a video stream. Since the WEBA format is an audio-only WebM variant, including any video stream would either cause an error or produce a non-standard file. The -vn flag ensures a clean, audio-only output regardless of what's embedded in the source WMA.
Replace the value after -b:a in the command to set a different target bitrate. For example, use -b:a 96k for a smaller file with slightly reduced quality, or -b:a 192k for higher fidelity. Opus is remarkably efficient — 96k Opus often sounds as good as 128k WMA — so you may be able to target a lower bitrate than your original WMA without a noticeable quality difference. Supported options include 64k, 96k, 128k, 192k, 256k, and 320k.
Yes, you can adapt the command for batch processing in a terminal. On Linux or macOS, use a shell loop: for f in *.wma; do ffmpeg -i "$f" -c:a libopus -b:a 128k -vn "${f%.wma}.weba"; done. On Windows Command Prompt: for %f in (*.wma) do ffmpeg -i "%f" -c:a libopus -b:a 128k -vn "%~nf.weba". This processes each WMA file in the current directory and outputs a corresponding WEBA file. The browser-based tool on this page handles one file at a time, so the FFmpeg command is the recommended approach for bulk conversions.
Technical Notes
WMA files use Microsoft's Advanced Systems Format (ASF) container, which supports DRM (Digital Rights Management) — if your WMA file was purchased from an older Microsoft or Zune store and is DRM-protected, FFmpeg will be unable to decode it and the conversion will fail. Only DRM-free WMA files can be processed. The default audio codec for WMA is WMV2, though older files may use WMV1; both are handled identically by FFmpeg's decoder. On the output side, libopus (the Opus encoder) is notably superior to libvorbis at low-to-mid bitrates, which is why it's selected as the default over Vorbis for this conversion. Opus also has a lower inherent latency, making WEBA/Opus better suited for streaming contexts than WMA ever was outside of Windows Media ecosystems. One limitation to be aware of: the WEBA container does not support chapter markers or multiple audio tracks, though WMA itself doesn't support these features either, so no data of this kind will be lost. File sizes will typically be slightly smaller with WEBA/Opus at equivalent bitrates due to Opus's more modern compression algorithms.