Convert FLV to WMA — Free Online Tool
Convert FLV video files to WMA audio by extracting the audio stream and re-encoding it using Microsoft's WMA v2 codec. This is ideal for pulling audio from Flash-era video content into a format natively supported by Windows Media Player and compatible Microsoft ecosystem applications.
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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
FLV files typically carry audio encoded in AAC or MP3 alongside a video stream (usually H.264). During this conversion, FFmpeg discards the video stream entirely and re-encodes only the audio into WMA format using the wmav2 codec — Microsoft's second-generation Windows Media Audio encoder. Because WMA is an audio-only container, there is no remuxing of video; this is a pure audio transcode. The AAC or MP3 audio from the FLV is decoded to raw PCM internally and then re-encoded to WMA at the target bitrate (default 128k), which means this is a lossy-to-lossy transcode and involves a small but measurable generation loss compared to the original source.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool. In this browser-based tool, the equivalent FFmpeg.wasm (WebAssembly) binary runs locally in your browser, processing your FLV file without uploading it to any server. |
-i input.flv
|
Specifies the input file — your source FLV (Flash Video) file. FFmpeg will read the container and identify both the video stream (typically H.264) and the audio stream (typically AAC or MP3) inside it. |
-c:a wmav2
|
Sets the audio codec to wmav2 (Windows Media Audio version 2), Microsoft's second-generation WMA encoder. This re-encodes the audio from the FLV's native codec (AAC or MP3) into the WMA format required for the .wma output container. |
-b:a 128k
|
Sets the audio bitrate to 128 kilobits per second for the WMA output. This is the default balance between file size and audio quality for WMA; you can increase this to 192k or 256k if you want to minimize quality loss from the lossy-to-lossy re-encode. |
output.wma
|
Defines the output filename with the .wma extension, which tells FFmpeg to wrap the encoded audio in the ASF (Advanced Systems Format) container that WMA files use. Because WMA is audio-only, FFmpeg automatically drops the video track from the FLV without requiring any additional flags. |
Common Use Cases
- Extracting spoken commentary or narration from old Flash-based e-learning or tutorial videos to archive in WMA format for Windows Media Player libraries
- Converting FLV recordings from legacy Flash-based streaming platforms (e.g., early YouTube downloads, Justin.tv archives) into WMA for use in Windows-centric media management software like Windows Media Center
- Preparing audio tracks from FLV video files for distribution through older Microsoft Zune or Windows Phone devices that natively supported WMA
- Stripping audio from FLV screencasts or webinar recordings to produce WMA files for corporate intranet audio libraries that mandate Microsoft-compatible formats
- Migrating a collection of downloaded Flash video podcasts or video blogs into WMA for use in a Windows Media Player playlist or sync with WMA-compatible portable media players
Frequently Asked Questions
Yes, some quality loss is unavoidable. FLV files most commonly store audio as AAC or MP3, both of which are lossy formats. Converting to WMA means decoding that lossy audio to raw PCM and re-encoding it with the wmav2 codec — a lossy-to-lossy transcode. The degree of degradation depends on the original bitrate and the target WMA bitrate, but at 128k both formats are perceptually similar in quality. If audio fidelity is critical, increasing the output bitrate to 192k or 256k can help offset the re-encoding penalty.
Because WMA is a pure audio container format, FFmpeg automatically understands that video cannot be written to a .wma output file and drops the video stream without requiring an explicit -vn flag. The output container itself enforces audio-only output, so no additional flag is needed to suppress the video track from the source FLV.
wmav1 is the original Windows Media Audio codec from 1999, while wmav2 is an improved version released around 2000 with better compression efficiency and audio quality at equivalent bitrates. This tool defaults to wmav2 because it offers noticeably better quality than wmav1 at the same file size and is still universally supported by any player that handles WMA. You can switch to wmav1 in the FFmpeg command by changing -c:a wmav2 to -c:a wmav1, but there is rarely a reason to do so.
Replace the 128k value in the -b:a 128k flag with your desired bitrate. For example, use -b:a 192k for higher quality or -b:a 96k for a smaller file. The WMA format supports bitrates from 64k up to 320k. Since this conversion involves a lossy-to-lossy re-encode from the FLV's existing audio, using at least 128k–192k is recommended to avoid compounding quality loss, especially if the source FLV had high-bitrate audio.
FLV files have limited metadata support and rarely carry rich audio tags, so there is typically very little metadata to transfer. WMA does support metadata tags (including title, artist, album, and copyright fields), but FFmpeg will only copy over what is present in the source FLV. In practice, you may need to add metadata manually after conversion using a tag editor or by appending -metadata title='My Title' style flags to the FFmpeg command.
The single-file command shown here processes one file at a time, but you can adapt it for batch processing in a terminal. On Linux or macOS, use: for f in *.flv; do ffmpeg -i "$f" -c:a wmav2 -b:a 128k "${f%.flv}.wma"; done. On Windows Command Prompt, use: for %f in (*.flv) do ffmpeg -i "%f" -c:a wmav2 -b:a 128k "%~nf.wma". This is especially useful for converting large collections of archived FLV files where the browser-based tool's 1GB per-file limit would be a constraint.
Technical Notes
FLV (Flash Video) is a container that carries video (typically H.264 or the older Sorenson Spark codec) alongside audio (AAC or MP3). When converting to WMA, only the audio pipeline is relevant — the video is silently discarded because WMA is an audio-only format. The wmav2 codec used here is a fixed-bitrate lossy encoder; unlike AAC or MP3 which have well-established quality-based encoding modes (like CRF or VBR quality scales), wmav2 in FFmpeg is primarily controlled via -b:a (average bitrate). WMA files produced by wmav2 are broadly compatible with Windows Media Player, Windows Media Center, Xbox consoles, and many older portable media players that predate the smartphone era. One notable limitation is that WMA has essentially zero support in modern web browsers natively and is not playable in most non-Microsoft media ecosystems without additional codec packs. The format does support DRM (Digital Rights Management) at a container level, though FFmpeg does not apply DRM — the output files from this tool will be unprotected WMA. Metadata such as ID3-style tags is supported in WMA via ASF (Advanced Systems Format) metadata fields, but FLV sources typically carry minimal metadata to pass through.