Extract Audio from RMVB to WMA — Free Online Tool
Extract audio from RMVB files and convert it to WMA format using the wmav2 codec — entirely in your browser, with no file uploads. Ideal for pulling audio tracks out of RealMedia video content and repackaging them in a Microsoft-compatible streaming format.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your RMVB file here
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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
RMVB files typically carry audio encoded in AAC or MP3 alongside a compressed video stream. During this conversion, FFmpeg discards the video stream entirely using the -vn flag and re-encodes the audio track using the wmav2 codec, which is the standard Windows Media Audio version 2 encoder. Because the source audio (AAC or MP3) is not natively compatible with the WMA container, a full audio transcode is required — the audio is decoded from its original codec and re-encoded as wmav2 at 128k bitrate by default. This means there is a small, predictable quality cost from transcoding, but the result is a compact, streaming-ready WMA file that plays natively on Windows and in Windows Media Player without any additional codecs.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, the open-source multimedia processing engine that powers this conversion. In the browser, this runs as FFmpeg.wasm compiled to WebAssembly. |
-i input.rmvb
|
Specifies the input file — an RMVB (RealMedia Variable Bitrate) file. FFmpeg uses its rmvb demuxer to read the container and expose its audio and video streams for processing. |
-vn
|
Disables video output entirely, telling FFmpeg to ignore the video stream from the RMVB file. This is what makes the tool an audio extractor — only the audio track is passed forward to be re-encoded. |
-c:a wmav2
|
Sets the audio codec to wmav2 (Windows Media Audio version 2), the modern standard WMA codec. Because AAC and MP3 from RMVB cannot be stored natively in a WMA container, the audio is fully re-encoded using this codec. |
-b:a 128k
|
Sets the audio output bitrate to 128 kilobits per second for the wmav2 encoder. This is a widely used default that balances file size and audio quality; for music or higher-fidelity needs, increasing this to 192k or 256k is recommended. |
output.wma
|
Defines the output filename with a .wma extension. FFmpeg uses this extension to select the ASF container format, which is the standard container for WMA audio files, compatible with Windows Media Player and most Windows-native media software. |
Common Use Cases
- Extracting commentary or narration audio from RMVB documentary or lecture recordings to create a standalone WMA audio file for Windows Media Player playlists
- Converting old RMVB music video files downloaded in the early 2000s into WMA audio tracks compatible with Windows-based portable media players and Zune devices
- Archiving the audio from RMVB television broadcasts or streamed content into WMA format for use in Windows media libraries or SharePoint media repositories
- Stripping audio from RMVB anime or foreign film files to produce a WMA track that can be used as background music or reference audio in a Windows-native editing workflow
- Pulling speech audio from RMVB conference recordings and saving as WMA for distribution via systems that use Windows Media DRM or streaming infrastructure
- Extracting audio from RMVB training or tutorial videos to create WMA audio guides for offline playback on Windows-centric corporate devices
Frequently Asked Questions
Yes, there will be a minor quality loss because this conversion requires a full audio transcode. The original audio in the RMVB file (usually AAC or MP3) must be fully decoded and then re-encoded into the wmav2 codec — there is no way to copy the audio stream directly since AAC and MP3 are not valid codecs inside a WMA container. At the default 128k bitrate, the result is generally transparent for speech and acceptable for most music, but audiophiles may want to raise the bitrate to 192k or 256k to minimize generational loss.
WMA version 2 (wmav2) is the modern standard and offers better audio quality at equivalent bitrates compared to the older wmav1 codec. wmav1 is a legacy format from the late 1990s and is rarely needed today. Unless you specifically need to play the output on an extremely old device that only supports WMA version 1, wmav2 is the correct choice and is the default used by FFmpeg for WMA output.
No. Even if the RMVB source file contained chapter markers or subtitle streams, none of that information is preserved in this conversion. WMA does not support subtitles or chapters, and the tool is configured to extract only the audio track. The output WMA file will contain only the audio stream, though basic metadata tags such as title and artist may be preserved if they were embedded in the original RMVB file.
Adjust the -b:a flag in the command to change the output audio bitrate. For example, replace 128k with 192k or 256k for higher quality: ffmpeg -i input.rmvb -vn -c:a wmav2 -b:a 192k output.wma. WMA supports bitrates from 64k up to 320k. Higher bitrates produce larger files but reduce the quality penalty from transcoding the original AAC or MP3 audio.
Almost certainly yes. RMVB files contain both a video stream and an audio stream, and the video data typically accounts for the vast majority of the file size. By stripping the video with -vn and keeping only the audio re-encoded at 128k, the resulting WMA file will often be 10 to 30 times smaller than the source RMVB, depending on the original video's duration and quality settings.
The browser-based tool processes one file at a time, but if you copy the displayed FFmpeg command to run locally on your desktop, you can batch process using a shell loop. On Linux or macOS: for f in *.rmvb; do ffmpeg -i "$f" -vn -c:a wmav2 -b:a 128k "${f%.rmvb}.wma"; done. On Windows Command Prompt: for %f in (*.rmvb) do ffmpeg -i "%f" -vn -c:a wmav2 -b:a 128k "%~nf.wma". This is especially useful for files over 1GB, which exceed the browser tool's limit.
Technical Notes
RMVB (RealMedia Variable Bitrate) is a legacy container developed by RealNetworks, and support for it in modern software is limited — FFmpeg handles it through the rmvb demuxer and can decode the audio stream whether it is AAC or MP3. WMA uses the ASF (Advanced Systems Format) container developed by Microsoft, and the wmav2 codec is the standard audio codec within it. Because neither AAC nor MP3 can be placed directly inside an ASF/WMA container, this conversion always involves a full decode-and-reencode cycle, making bitrate selection meaningful: the default 128k is a reasonable balance of file size and fidelity, but for music content originally encoded at high quality, bumping to 192k or 256k is advisable. WMA supports metadata tags (title, artist, album, etc.) via ASF's native metadata system, so any embedded tags from the RMVB source may survive if FFmpeg can map them. DRM (Digital Rights Management) is a feature of the WMA ecosystem, but FFmpeg does not add DRM during encoding — the output will be an unprotected WMA file. Variable bitrate mode (VBR) is also possible with wmav2 using the -q:a flag instead of -b:a, though the browser tool uses constant bitrate for predictability.