AVI to MP4 converter
Convert AVI to MP4 free online. Modernize old camcorder and Windows video clips for any device. No signup, 500 MB limit, files deleted in 1 hour.
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About MPEG-4 Video Format
Common Use Cases
- Converting legacy AVI video files
- Enabling playback on modern devices
- Reducing file sizes of old video archives
AVI (Audio Video Interleave) is a container format Microsoft introduced back in 1992, and you still run into it in old home-video archives, screen recordings, and clips downloaded a long time ago. The problem with AVI is that it often wraps outdated codecs like DivX, XviD, or Cinepak that modern devices either cannot decode or handle poorly. Converting to MP4 with H.264 gives you a file that plays everywhere, streams better, and is often dramatically smaller.
AVI is a legacy container that usually ships with older, less efficient codecs, while MP4 with H.264 typically produces a smaller file at the same visual quality and plays natively on every current device without plugins.
Why Convert AVI to MP4?
Smaller files with better compression
AVI containers most often carry DivX, XviD, or straight MPEG-4 Part 2 video, all of which are far less efficient than modern H.264. Re-encoding into MP4 with H.264 typically cuts file size by 30 to 60 percent at the same perceptual quality, which matters when you are uploading, emailing, or storing a pile of old clips.
Universal playback on modern devices
iPhones, iPads, Android phones, Chromebooks, and smart TVs often refuse to play AVI or stutter through it. MP4 is the default video container for every current operating system and browser, so the converted file just works without chasing down codec packs or third-party players.
Upload to any platform without errors
YouTube, Instagram, Facebook, and cloud storage services generally accept AVI but will re-encode it on their servers, sometimes badly. Uploading an MP4 that you encoded yourself gives you control over the final quality instead of leaving it to a black-box upload pipeline.
Stream cleanly and seek instantly
AVI was never designed for modern streaming, so seeking in a web player or scrubbing through the timeline can be slow or unreliable. MP4 with proper moov-atom placement supports progressive download and fast seeking, which is what any browser video player expects.
When to use each
Use AVI when...
- Working with legacy Windows software from the 2000s
- Importing into old non-linear editors
- Reading archived DivX or XviD rips
- Opening in tools that only read AVI
- Preserving an original untouched archive
Use MP4 when...
- Playing on phones, tablets, or smart TVs
- Uploading to YouTube, Vimeo, or social platforms
- Sharing clips via messaging or email
- Embedding video on a website or app
- Shrinking file size for cloud storage
Common use cases
- Converting legacy AVI video files
- Enabling playback on modern devices
- Reducing file sizes of old video archives
How to use
- Upload your AVI file. Drag and drop your AVI video onto the upload area, or click to select a file from your computer. Files up to 500 MB per upload are supported, which handles most short clips and standard-def archives comfortably.
- Start the conversion. Click Convert File to send your video to our servers for processing with FFmpeg. The converter re-encodes the AVI into an H.264 MP4 with AAC audio, producing a file that plays cleanly on modern devices.
- Download your MP4 file. When the conversion finishes, a download link appears. Save the MP4 to your device and it is ready to share, upload, or play anywhere. Both your original upload and the output are automatically deleted within 1 hour.
Frequently asked questions
- Will converting AVI to MP4 improve or reduce quality?
- The conversion cannot improve quality beyond what the source AVI contains, but it rarely makes it visibly worse either. H.264 inside MP4 is much more efficient than the DivX and XviD codecs typically found in AVI, so the output usually looks identical to the source while being smaller. Quality is capped by the original encode.
- Why is my AVI file not playing on my phone?
- Most phones do not ship with decoders for the codecs found in older AVI files, like DivX, XviD, or legacy MPEG-4. Converting to MP4 with H.264 solves the compatibility issue instantly because H.264 is supported natively by iOS and Android.
- Why is the MP4 smaller than my AVI?
- H.264 compresses much more efficiently than the codecs typically found inside AVI containers. It is common to see 30 to 60 percent size reduction at the same visual quality, which is why MP4 has become the default for sharing and streaming video.
- Is there a file size limit?
- Yes, each upload is capped at 500 MB. If your AVI is larger than that, clip out the section you need or compress it first with a local tool like Handbrake before uploading.
- Is converting AVI to MP4 free?
- Yes. Free anonymous use is available with a daily conversion cap, and registered FileFactory accounts get a higher daily allowance. Premium and Lifetime members enjoy unlimited conversions.
- How long do you keep my files?
- Uploaded videos and the converted MP4 output are automatically deleted within 1 hour. Transfers are encrypted and we never share your files with third parties.
- Can I convert AVI to MP4 without losing the audio track?
- Yes. The audio track is preserved through the conversion and re-encoded to AAC, which is the standard audio codec for MP4 and works on every device. Volume, timing, and sync are maintained.