Convert WMV to FLV — Free & Private
WMV (Windows Media Video) files were the default output of Windows Movie Maker, Microsoft Expression Encoder, and early screen-recording tools. Corporate training libraries, 2000s home movies, and screen captures from older Windows machines are commonly stored as WMV. Modern browsers, Mac, iOS, and Android all lack native WMV support, making conversion essential before sharing or archiving these files. Converting to FLV is only needed for legacy Flash-based systems. Note that Flash Player is permanently end-of-life since December 2020 — produce FLV only for specific legacy system compatibility.
How to Convert WMV to FLV
Click "Convert Now" to open with WMV → FLV pre-selected.
Drag & drop your WMV file or click Browse.
FFmpeg.wasm processes your video locally — nothing uploaded.
Your converted FLV file downloads automatically.
Why Convert WMV to FLV?
- 🖥️ From WMV — convert Windows Media Video to formats with broader cross-platform support
- 🌐 Legacy web video — FLV was the standard for web video before HTML5
- 📦 Compact size — efficient compression for smaller file sizes
- 🔄 Flash compatible — works with legacy Flash-based video players
- 🎬 Streaming-ready — optimised for progressive streaming delivery
- 🔒 100% private — files never leave your device
WMV vs FLV — Format Comparison
Features
100% Private
Files never leave your browser.
Instant
In-browser processing, no waiting.
Free
No account, no fee, no watermarks.
Quality Preserved
High-quality settings by default.
Mobile-Friendly
Works on any device.
No Install
Works in any modern browser.
Key Questions About WMV to FLV, Answered
Direct answers structured for AI extraction, voice search, and featured snippets.
Will my video be re-encoded or just remuxed when converting WMV to FLV?
Always re-encoded. FLV only accepts H.264+AAC or the older VP6/Sorenson H.263, and WMV's VC-1/WMV3 video can't be placed inside an FLV container as-is. Convertlo decodes the video and re-encodes it to H.264, converting the audio to AAC or MP3.
- VC-1-in-WMV → FLV: full re-encode to H.264, no shortcut available
- FLV is itself a legacy container — only convert to it if older software specifically requires it
- Audio is converted to AAC or MP3 as required by the FLV container
Does converting WMV to FLV reduce quality?
Yes — both VC-1 (WMV's codec) and H.264 (FLV's codec) are lossy, so re-encoding always causes some quality loss, even if subtle at normal viewing sizes.
- WMV uses VC-1, a Microsoft codec that compresses similarly to H.264 but less efficiently
- FLV re-encodes to H.264 — this adds a second generation of lossy compression
- At moderate bitrates the difference is minor; at low bitrates artefacts compound
- If quality matters, use the highest bitrate the destination tool accepts
How much will the file size change going from WMV to FLV?
VC-1, the codec inside WMV, is roughly comparable to H.264 in efficiency, so converting to FLV's H.264 typically lands close to the original size.
- VC-1-in-WMV → FLV: roughly similar size
- Audio re-encoding to AAC/MP3 has only a minor effect on overall size
- Bitrate settings during re-encoding have more impact on size than the codec swap itself
Why does my old WMV file stop playing on modern devices?
WMV relies on Microsoft's VC-1 codec, which Windows supports natively but which iOS, macOS, and most Android devices never adopted without an extra codec pack. Converting to FLV doesn't fix this — FLV has had essentially no device support since Flash Player was discontinued in December 2020.
- iPhone, iPad, and most Android phones: no native WMV or FLV playback
- Web browsers: neither WMV nor FLV plays inline anymore
- For playback on phones, browsers, and streaming devices, MP4 is the better target
- Use FLV only when a specific legacy tool requires that exact container
Go Deeper: WMV to FLV Resources
In-depth articles to help you understand the formats, pick the right settings, and get the best results.