AVI to FLV Converter

What happens when you convert AVI to FLV

• The video is re-encoded to H.264 video with AAC audio.
• Re-encoding in a browser is slow: expect several times the video's length for HD footage on a laptop, and longer on a phone. Short and low-resolution clips finish much sooner.

How to convert AVI to FLV online

1. Press "Choose AVI files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
2. Adjust the settings if you need to: resolution and quality control the size of the result. The defaults suit most people.
3. Press "Convert to FLV". The first audio or video conversion downloads the converter engine, about 32 MB, which your browser then keeps for next time.
4. Save each FLV with its download button. Close the tab and every trace of the files is gone from memory.

Why convert AVI to FLV?

AVI files usually come from older camcorders, digital cameras and legacy video libraries. People convert them to FLV because FLV is still requested by a few legacy streaming and e-learning systems.

In short, AVI is good at what it was made for, and FLV is the more practical choice when the file has to play, upload or edit somewhere else. AVI does not play in browsers; plays in VLC and Windows players, while FLV does not play in browsers since Flash ended in 2020; plays in VLC.

How to convert AVI to FLV on Windows, Mac, iPhone and Android

On Windows

Open this page in Chrome, Edge or Firefox, drag your AVI files in from File Explorer, and press Convert. Each FLV is saved to your Downloads folder. If you prefer a desktop program, VLC can also convert AVI to FLV: choose Media, then Convert / Save.

On a Mac

Safari, Chrome and Firefox all work. Drag the AVI files from Finder onto the drop zone and the FLV files land in Downloads.

On iPhone and iPad

Open the page in Safari and tap Choose AVI files. You can pick from Photos or from the Files app. The converted FLV appears in Files, in the Downloads folder; to put it in your photo library, open it there, tap Share and choose Save Video.

On Android

Open the page in Chrome, tap Choose AVI files and pick them from Files or your gallery. The FLV is saved to the Download folder, where any file manager can find it. Keep the screen on while a long video converts, because Android may pause a tab in the background.

Best settings for AVI to FLV

FLV is written as H.264 video with AAC audio. The Resolution setting is the one to reach for: 1080p keeps full HD detail, 720p is plenty for phones and laptops and roughly halves the size, and 480p suits email and old devices.

The quality levels map to the H.264 CRF scale where the target uses H.264, and to fixed high-quality settings for older codecs such as MPEG-2, MPEG-4 Part 2, WMV and Theora. Re-encoding always costs a little detail, so convert from the best copy of the AVI you have.

AVI vs FLV: the differences

About AVI and FLV files

What is an AVI file?

AVI dates from Windows 3.1 and predates the codecs most people use today. It is still readable by almost every desktop editor, which is why some older software asks for it.

What is an FLV file?

FLV powered YouTube and most web video until about 2010. Since browsers dropped Flash at the end of 2020, FLV files need converting or a desktop player.

AVI to FLV not working? Common problems

• The conversion is slow. Audio and container changes take seconds, but re-encoding video runs on your own processor. Lower the resolution to 720p, close other tabs, and keep the device plugged in.
• The tab stops or reloads on a very large file. Browsers limit how much memory one tab can use, around 2 GB and less on phones. Split long recordings or convert them on a computer.
• The FLV will not play on an old device. Try the other formats offered for AVI, or choose 720p, which older players handle more reliably.

Convert AVI to FLV with ffmpeg

This converter runs ffmpeg inside your browser. If you would rather use the ffmpeg command line on your own computer, this command produces an equivalent FLV with the same kind of settings:

ffmpeg -i input.avi -c:v libx264 -crf 23 -c:a aac -ar 44100 output.flv

Replace input.avi with the name of your file. For a whole folder of AVI files, run the command in a loop, or drop them all on the converter above, which processes them one after another.