Extract Audio from WebM to WMA — Free Online Tool
Extract and convert the audio track from a WebM file (encoded with Opus or Vorbis) into a WMA file using Microsoft's wmav2 codec. Ideal for getting Windows-compatible audio out of web-optimized video containers without retaining the VP9 video stream.
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FFmpeg Command
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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
WebM files typically carry audio encoded in either Opus or Vorbis — both open-source codecs optimized for web streaming. WMA is a proprietary Microsoft format that uses the wmav2 codec. Because these audio codecs are fundamentally incompatible, a full audio transcode is required: the Opus or Vorbis audio stream is decoded to raw PCM and then re-encoded into wmav2 at the target bitrate (default 128k). The VP9 video stream is discarded entirely using the -vn flag — this is an audio extraction, not a container remux. The result is a standalone .wma file containing only the re-encoded audio, suitable for Windows Media Player and legacy Windows ecosystems.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine that handles decoding the WebM container, transcoding the Opus/Vorbis audio stream, and writing the WMA output file. |
-i input.webm
|
Specifies the input WebM file. FFmpeg will detect the container (WebM/Matroska) and identify the contained streams, typically a VP9 video stream and an Opus or Vorbis audio stream. |
-vn
|
Disables video output entirely, ensuring the VP9 video stream from the WebM file is not processed or included. Since WMA is an audio-only format, this flag prevents any attempt to encode video and speeds up the extraction. |
-c:a wmav2
|
Sets the audio encoder to wmav2 (Windows Media Audio v2), the default and most compatible codec for the .wma container format. The Opus or Vorbis audio is fully decoded from the WebM and then re-encoded using the wmav2 encoder. |
-b:a 128k
|
Sets the output audio bitrate to 128 kilobits per second for the wmav2 encoder, producing a constant bitrate WMA stream. This is the default balance between file size and audio quality; raise it to 256k or 320k for better fidelity from the transcoded audio. |
output.wma
|
Defines the output filename and tells FFmpeg to write a WMA-format file. The .wma extension signals FFmpeg to use the ASF/WMA muxer, which is the standard container for Windows Media Audio content. |
Common Use Cases
- Converting browser-recorded WebM audio/video (e.g., from a video call or screen capture) into WMA for playback in Windows Media Player or older Windows applications that don't support WebM or Opus.
- Stripping the audio from a WebM lecture or tutorial download and saving it as WMA for playback on older portable media players or in-car stereos that support WMA but not Opus.
- Preparing audio content for integration into legacy Windows-based presentation or e-learning software that requires WMA input files.
- Archiving the audio commentary from a WebM video file in WMA format to match an existing library of Windows Media Audio files on a corporate or enterprise system.
- Extracting background music or sound effects stored in a WebM file and converting them to WMA for use in Windows Movie Maker or other Windows-native multimedia editors.
- Converting YouTube-downloaded WebM audio tracks (which use Opus codec) to WMA for distribution on platforms or devices that specifically require the WMA format.
Frequently Asked Questions
Yes, this conversion involves two generations of lossy compression. The source Opus or Vorbis audio in the WebM file is already lossy, and re-encoding it to wmav2 introduces a second round of compression artifacts. At the default 128k bitrate, the quality loss is generally acceptable for casual listening, but audiophiles or producers should use the highest available bitrate (320k) to minimize degradation. There is no lossless path from WebM to WMA since WMA only supports lossy encoding.
No. The WMA container exclusively supports Microsoft's own wmav2 (and the older wmav1) codecs — it cannot store Opus, Vorbis, or any other third-party audio codec. This is why a full transcode is necessary rather than a simple stream copy. The Opus or Vorbis data must be fully decoded and then re-encoded into wmav2 to produce a valid .wma file.
WMA supports common metadata tags such as title, artist, album, and year, and FFmpeg will attempt to map compatible tags from the WebM source to the WMA output. However, not all metadata fields present in a WebM or Matroska container have direct equivalents in the WMA format, so some tags may be dropped or left empty. If metadata accuracy is important, verify the output tags using a tool like MediaInfo or Windows Explorer's file properties after conversion.
Yes. Replace the -b:a 128k value with any supported bitrate: 64k for smaller files with lower quality, or up to 320k for the best possible WMA quality given the lossy transcode. For example, to get a higher-quality output, use: ffmpeg -i input.webm -vn -c:a wmav2 -b:a 256k output.wma. Keep in mind that exceeding the bitrate of the original WebM audio will not recover lost quality — it will only increase file size.
The single-file command shown won't process multiple files on its own, but you can wrap it in a shell loop. On Linux or macOS, use: for f in *.webm; do ffmpeg -i "$f" -vn -c:a wmav2 -b:a 128k "${f%.webm}.wma"; done. On Windows Command Prompt, use: for %f in (*.webm) do ffmpeg -i "%f" -vn -c:a wmav2 -b:a 128k "%~nf.wma". The browser-based tool processes files one at a time, so the FFmpeg command is especially useful for batch workflows on large file sets.
The -vn flag in the command explicitly tells FFmpeg to discard all video streams from the WebM source. WMA is a pure audio format with no capacity to store video data, so even without -vn the video would be dropped. Including -vn is best practice because it prevents FFmpeg from attempting any video processing, making the conversion faster and the intent of the command unambiguous.
Technical Notes
The wmav2 codec used here is the second-generation Windows Media Audio codec, introduced with Windows Media Player 7 and still widely supported across Windows software. It produces CBR (constant bitrate) output at the specified -b:a value, which means the bitrate is uniform across the entire file — unlike Opus, which by default operates in variable bitrate mode for perceptual efficiency. As a result, WMA files from this conversion may be larger than the Opus-encoded audio in the source WebM at equivalent perceptual quality levels, since Opus is a significantly more modern and efficient codec. WMA does not support multiple audio tracks, chapters, or embedded subtitles — all of these features present in the WebM source will be silently discarded. If the WebM file contains multiple audio tracks (e.g., multiple language streams), only the first audio track will be transcoded by default; use -map 0:a:1 to select a different track. The WMA format does support DRM (Digital Rights Management) encryption, but FFmpeg does not apply DRM during encoding, so the output file will be an unprotected WMA. File sizes will vary depending on source duration and selected bitrate, but a rough estimate is approximately 1 MB per minute at 128k.