Convert CAVS to WMA — Free Online Tool
Convert CAVS video files to WMA audio by extracting and re-encoding the AAC audio track using the Windows Media Audio v2 (wmav2) codec. This is ideal for pulling audio from Chinese broadcast-standard CAVS content into a widely compatible Windows-native audio format.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your CAVS 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
CAVS files contain a video stream encoded with H.264 (libx264) and an audio stream encoded with AAC. Since WMA is a pure audio container, the video stream is completely discarded during this conversion — no video data is carried over. The AAC audio track is decoded and then re-encoded from scratch into Windows Media Audio v2 (wmav2), which is a lossy compression format developed by Microsoft. Because both AAC and WMA are lossy codecs, this is a lossy-to-lossy transcode, meaning each encoding step introduces some generation loss. The output is a .wma file containing only the re-encoded audio at the specified bitrate (default 128k), with no subtitle, chapter, or metadata track support in the output container.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that handles the CAVS decoding, AAC-to-wmav2 audio transcoding, and WMA container writing in this conversion. |
-i input.cavs
|
Specifies the input file, a CAVS-formatted video containing an H.264 video stream and an AAC audio stream. FFmpeg reads and demuxes both streams, though only the audio will be used in the WMA output. |
-c:a wmav2
|
Instructs FFmpeg to encode the audio stream using the Windows Media Audio v2 codec (wmav2), Microsoft's improved proprietary lossy audio codec that produces the .wma output. The source AAC audio is fully decoded and re-encoded into this format. |
-b:a 128k
|
Sets the audio bitrate for the wmav2 encoder to 128 kilobits per second, the default quality setting. This produces a reasonable balance between file size and audio fidelity for typical broadcast speech and general audio content extracted from CAVS files. |
output.wma
|
Defines the output filename and instructs FFmpeg to write a WMA container. The .wma extension signals FFmpeg to use the Windows Media Audio container format, which holds only the re-encoded wmav2 audio stream with no video. |
Common Use Cases
- Extracting dialogue, narration, or music from Chinese broadcast CAVS recordings for use in Windows Media Player or legacy Microsoft media ecosystems
- Archiving the audio commentary track from a CAVS-encoded broadcast segment into a lightweight WMA file for distribution on Windows-centric platforms
- Preparing audio from CAVS source material for use in older Windows applications or devices that support WMA but not AAC or CAVS
- Stripping the audio from a CAVS broadcast clip to create a standalone WMA file for inclusion in a Windows-based digital media library
- Converting CAVS audio to WMA for use with DRM-enabled Windows Media workflows, taking advantage of WMA's built-in DRM support features
- Reducing storage footprint by discarding the H.264 video stream from a CAVS file and retaining only the re-encoded audio in a compressed WMA format
Frequently Asked Questions
Yes, some quality loss is unavoidable. The original CAVS file stores audio as AAC, which is already a lossy format. Converting to WMA (wmav2) requires fully decoding the AAC audio and re-encoding it into a different lossy codec, which introduces a second generation of compression artifacts. To minimize the loss, use a higher output bitrate such as 192k or 256k. However, no transcode between two lossy formats is truly transparent.
WMA is a pure audio container format — it has no capacity to store video streams. FFmpeg automatically drops the video track when writing to a .wma output file. If you need to retain the video, you would need to convert to a container that supports both audio and video, such as MP4 or MKV.
WMA does support metadata tags such as title, artist, and album. However, CAVS files originating from broadcast contexts may carry little or no embedded metadata, so the WMA output may also have sparse or empty tags. FFmpeg will attempt to copy any compatible metadata it finds in the CAVS container, but there is no guarantee of a complete transfer.
Change the value of the -b:a flag in the command. For example, replace -b:a 128k with -b:a 192k for higher quality, or -b:a 96k for a smaller file. The default is 128k, which is a reasonable balance for speech and general audio. For music or high-fidelity content extracted from broadcast CAVS files, 192k or 256k is recommended.
Yes, you can substitute -c:a wmav1 for -c:a wmav2 in the command if you need compatibility with very old Windows Media Player versions or legacy hardware. However, wmav2 is the recommended default because it offers better audio quality at the same bitrate and is supported by essentially all modern and legacy Windows Media-compatible players.
Yes, using a shell loop. On Linux or macOS, run: for f in *.cavs; do ffmpeg -i "$f" -c:a wmav2 -b:a 128k "${f%.cavs}.wma"; done. On Windows Command Prompt, use: for %f in (*.cavs) do ffmpeg -i "%f" -c:a wmav2 -b:a 128k "%~nf.wma". This processes each CAVS file in the current directory and outputs a corresponding WMA file with the same base name.
Technical Notes
CAVS (Chinese Audio Video Standard) is a broadcast-oriented format developed as a domestic Chinese alternative to H.264/AVC, and its audio track is typically AAC-encoded. WMA (Windows Media Audio) uses Microsoft's proprietary wmav2 codec and is historically associated with Windows Media Player, Zune, and Microsoft's DRM ecosystem. Because this conversion strips all video data and transcodes AAC to wmav2, the output file will always be significantly smaller than the source CAVS file. The wmav2 codec supports bitrates from 64k to 320k; at 128k it is generally comparable in perceived quality to AAC at 128k for speech content, though AAC tends to outperform wmav2 at equivalent bitrates for complex music. WMA does not support multiple audio tracks, embedded subtitles, or chapters, so any such elements in the source CAVS file are silently discarded. The WMA container does support DRM metadata fields, but FFmpeg will not apply any DRM protection during encoding — the output is unprotected. There are no special encoding flags required for this conversion beyond the codec and bitrate selection.