Convert AVI to MP4
AVI files from old cameras, DivX and Xvid downloads or Windows-era recordings often won’t play on phones or in browsers. Convert them to MP4 right on your device.
- No upload
- No watermark
- No file size limit
- Hardware accelerated
Drop videos here to convert them
MP4, MOV, WebM, MKV, AVI and more · no size limit or watermark
Processed on your device. Your videos are never uploaded.
Advanced: codec, frame rate, audio, trim
How to convert AVI to MP4
- 1
Add your AVI files
Drop one or more .avi files onto the tool. They are converted one after another.
- 2
Keep MP4 and High quality
The preset re-encodes the video to H.264 and the audio to AAC – the combination every device plays.
- 3
Wait for the first-time setup
Browsers can’t read AVI themselves, so the compatibility engine is downloaded once (about 30 MB) and then cached.
- 4
Download your MP4s
Each file keeps its name with a .mp4 extension. Preview it in the queue before you download.
Why AVI files cause trouble
AVI is a container Microsoft introduced in 1992. It can hold almost any codec, and old files typically use DivX or Xvid (MPEG-4 Part 2) video with MP3 or PCM audio. iPhones, many Android phones, smart TVs and web browsers don’t play those combinations, and upload sites often reject AVI outright.
MP4 with H.264 video and AAC audio is the opposite: it is the most widely supported video format there is. Converting gives your old clips a second life on modern devices.
How the conversion works in your browser
Asset Compressor normally uses your device’s hardware video encoder, but browsers can’t open AVI files. For these it switches to FFmpeg compiled to WebAssembly, which reads virtually every AVI variant and still runs entirely on your computer. It is several times slower than hardware encoding, so a long film can take a while – a computer is much faster at it than a phone.
Your videos are never uploaded, so there is no file size limit and no waiting in a server queue. Keep the tab open until the conversion finishes.
Lossless option for H.264 AVIs
Some newer AVI files already contain H.264 video. For those, choose “Original” quality: the video stream is copied into the MP4 without re-encoding, which is faster and loses nothing. If the codec can’t go into an MP4 unchanged, it is re-encoded automatically.
Converting a collection
Digitizing old family videos or a folder of camera clips? Add them all at once. The queue converts one file at a time so your device stays responsive, and you can download everything as a ZIP when it is done.
Frequently asked questions
Will converting AVI to MP4 lose quality?
The High preset keeps the difference practically invisible. For H.264 AVIs, “Original” copies the video without any loss at all.
Why is AVI conversion slower than MP4 compression?
Browsers can’t decode AVI with hardware, so the compatibility engine does the work in software on your processor.
Can I make the MP4 smaller at the same time?
Yes. Choose a lower quality level such as Balanced, or switch to “By file size” and enter the size you need.
Are my videos uploaded?
No. Everything happens in your browser and the files never leave your device.
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WMV was the standard on Windows for years, but Macs, iPhones and many apps no longer open it. Convert Windows Media Video to MP4 without uploading anything.
AVI to WebM
Need an old AVI clip on a website? Convert it to WebM with VP9 video and Opus audio – the open, royalty-free format every modern browser plays.
Compress video
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