Extract Audio from DVR to WMA — Free Online Tool
Extract audio from DVR recordings and convert it to WMA format using the Windows Media Audio v2 codec — ideal for archiving surveillance or broadcast audio in a format natively compatible with Windows Media Player and legacy Microsoft ecosystems. The conversion strips the video stream entirely and re-encodes the AAC or MP3 audio track from the DVR file into WMA at 128k bitrate by default.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
DVR files typically store video encoded with H.264 (libx264) and audio encoded with AAC or MP3, wrapped in a proprietary container used by digital video recorders. During this conversion, FFmpeg discards the video stream entirely using the -vn flag and extracts only the audio track. That audio is then decoded from its original codec (usually AAC) and re-encoded into the WMA format using the wmav2 (Windows Media Audio v2) codec. Because the source container is proprietary and the target audio codec differs from the source, a full decode-and-re-encode of the audio is required — this is not a lossless remux. The result is a standalone .wma file containing only the audio from your DVR recording.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles all media decoding, stream filtering, and re-encoding. In the browser-based version of this tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm) — no data leaves your device. |
-i input.dvr
|
Specifies the input DVR file. FFmpeg will attempt to detect the proprietary DVR container format and demux its video (typically H.264) and audio (typically AAC) streams for processing. |
-vn
|
Disables video output entirely, instructing FFmpeg to skip all video streams from the DVR file. Since WMA is an audio-only format and the goal is audio extraction, this flag ensures no video processing occurs. |
-c:a wmav2
|
Sets the audio encoder to wmav2, the Windows Media Audio v2 codec. This re-encodes the DVR's original audio (typically AAC) into the WMA format, which is required since the source and target audio codecs are different and a direct stream copy is not possible. |
-b:a 128k
|
Sets the audio bitrate for the WMA output to 128 kilobits per second. This is the default bitrate and provides a reasonable balance between file size and audio quality for the speech and ambient audio commonly found in DVR surveillance or broadcast recordings. |
output.wma
|
Defines the output filename and tells FFmpeg to write the result as a WMA file. The .wma extension signals FFmpeg to wrap the wmav2-encoded audio in the Windows Media Audio container format. |
Common Use Cases
- Extracting spoken audio or announcements from surveillance footage for use as evidence transcripts or documentation without sharing the video
- Archiving audio from broadcast TV recordings captured on a DVR into WMA for storage in a Windows Media Player library
- Converting DVR security camera audio into WMA files for playback on older Windows devices or media centers that natively support Windows Media Audio
- Stripping and saving the audio track from a DVR news or sports broadcast recording for later review without the large video file
- Providing audio-only exports of DVR footage to clients or colleagues who only need to hear conversations or ambient sound, not view the video
- Reducing file size significantly by discarding the H.264 video stream from a large DVR recording and retaining only the compressed WMA audio
Frequently Asked Questions
Yes, there will be some quality loss. DVR files typically store audio as AAC, which is already a lossy format. Converting that audio to WMA with wmav2 involves decoding the AAC stream and re-encoding it into a different lossy codec, which introduces a second generation of compression artifacts. At 128k bitrate, the WMA output is generally acceptable for speech and ambient sound — common in DVR recordings — but audiophiles or forensic analysts requiring maximum fidelity may want to increase the bitrate to 192k or 256k.
wmav2 (Windows Media Audio version 2) is the default and preferred codec because it offers better audio quality at the same bitrate compared to the older wmav1. Unless you specifically need compatibility with very old devices or software that only support Windows Media Audio v1, wmav2 is the correct choice. Most Windows applications, Windows Media Player, and modern media players that support WMA will handle wmav2 without any issues.
Yes. The -b:a flag controls the audio bitrate. To increase quality, replace 128k with a higher value such as 192k, 256k, or 320k — for example: ffmpeg -i input.dvr -vn -c:a wmav2 -b:a 192k output.wma. Keep in mind that since the original DVR audio is likely AAC at 128k, pushing the WMA bitrate significantly higher will increase file size without recovering detail that was already lost in the DVR encoding stage.
DVR files are proprietary and often embed recorder-specific metadata that FFmpeg cannot fully parse or map to WMA tags. Standard metadata fields like title or artist are unlikely to carry over, and DVR-specific data such as recording timestamps, camera channel IDs, or event markers will not be preserved in the WMA output. If preserving this information matters, document it separately before converting, as the WMA format supports standard ID3-style metadata tags but has no mechanism for DVR-specific fields.
On Linux or macOS, you can use a shell loop: for f in *.dvr; do ffmpeg -i "$f" -vn -c:a wmav2 -b:a 128k "${f%.dvr}.wma"; done. On Windows Command Prompt, use: for %f in (*.dvr) do ffmpeg -i "%f" -vn -c:a wmav2 -b:a 128k "%~nf.wma". This processes every DVR file in the current folder and outputs a matching .wma file. This approach is especially useful when dealing with multiple DVR recordings from the same surveillance session.
No video data is kept. The -vn flag explicitly instructs FFmpeg to ignore and discard all video streams from the DVR input. WMA is a pure audio container and has no capability to store video, so the output file will contain only the re-encoded audio track. This is intentional for this tool, which is designed specifically for audio extraction.
Technical Notes
DVR is a loosely defined proprietary container, and FFmpeg's ability to parse it depends on which DVR hardware or software produced the file. Most consumer and prosumer DVRs encode video in H.264 and audio in AAC at bitrates typically ranging from 64k to 128k — both of which FFmpeg handles well when it can read the container. The WMA output uses the wmav2 codec, which is Microsoft's second-generation Windows Media Audio codec and produces better quality than wmav1 at equivalent bitrates. WMA supports bitrates from 64k to 320k, giving meaningful headroom for quality adjustment. One known limitation is that WMA does not support multiple audio tracks, but DVR recordings rarely include more than one audio channel anyway. DRM features available in the WMA specification are not applied by this conversion — the output is an unprotected WMA file. File sizes will be dramatically smaller than the original DVR file since the video stream (often 90%+ of the file's data) is completely removed and only the audio track is retained.