AVI to FLV Converter
Convert AVI to FLV free — no upload, no signup
To convert AVI to FLV, drop your AVI video into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Encode AVI to H.264 FLV for streaming tools.
Drop videos here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
If the video already uses codecs that fit the new format, Fylo repackages it instantly with no quality loss.
Advanced
How to convert AVI to FLV
Add your AVI videos
Drag and drop AVI files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Choose quality (optional)
Balanced quality suits most videos. If the codecs already fit FLV, Fylo repackages the file instead of re-encoding it, with no quality loss.
Convert and download
Click Convert, then download each FLV file or all of them as one ZIP.
Why convert AVI to FLV?
If an RTMP streaming tool or legacy portal requires FLV, this turns AVI recordings into a file it accepts.
What happens when you convert AVI to FLV?
Xvid video isn't supported in modern FLV workflows, so Fylo re-encodes to H.264 with 44.1 kHz AAC audio. The FLV is usually smaller than the AVI.
How does Fylo convert AVI to FLV?
Fylo reads the AVI with ffmpeg compiled to WebAssembly and writes H.264 with AAC audio at 44.1 kHz, the sample rate Flash-era players expect. AVI's usual codecs (MPEG-4 Part 2 (Xvid/DivX), MJPEG) can't go into FLV as-is, so the video is re-encoded. Speed depends on your device: short phone clips take seconds, while on our slow test PC a 2-minute 1080p video took about 10 minutes. Only the first video and audio track are kept, and the original resolution is preserved unless you pick 1080p, 720p or 480p under Advanced.
What's the difference between AVI and FLV?
AVI (Audio Video Interleave) was introduced by Microsoft with Video for Windows in 1992. It's based on the RIFF container used by WAV and stores interleaved chunks of audio and video. In the 2000s, AVI files with DivX or Xvid (MPEG-4 Part 2) video and MP3 audio were the standard for downloaded movies.
FLV (Flash Video) was introduced with Flash Player 6 and 7 in 2002–2003 and became the format behind early YouTube, news sites and video portals. Later FLVs usually contain H.264 video and AAC audio — the same codecs as MP4.
Learn more: AVI format guide · FLV format guide
| Property | AVI | FLV |
|---|---|---|
| Developed by | Microsoft | Macromedia / Adobe |
| Introduced | 1992 | 2003 |
| Typical video codecs | MPEG-4 Part 2 (Xvid/DivX), MJPEG | H.264, Sorenson Spark, VP6 |
| Typical audio codecs | MP3, PCM, AC-3 | AAC, MP3 |
| Plays in web browsers | No | No (Flash Player ended in 2020) |
| Compatibility | Windows, VLC, older DVD players and TVs | VLC and some desktop players; RTMP live-streaming tools |
| Best for | Legacy players, old Windows software | Old Flash archives, RTMP streaming workflows |
Frequently asked questions
Can I play FLV on my phone?
Only with third-party players. Convert to MP4 for phone playback.
Is the audio converted too?
Yes, MP3 or PCM audio becomes AAC at 44.1 kHz.
Is my AVI file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your AVI file is read directly from your device and never sent anywhere.
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