Why convert AVI to MP4?
AVI files often contain older codecs that phones, browsers, messaging apps, and smart TVs do not decode consistently. MP4 with H.264 video and AAC audio has much broader playback and upload support, and it usually delivers a smaller file at comparable visual quality.
What changes during AVI to MP4 conversion?
The video is re-encoded to H.264 and any audio track is converted to AAC. Re-encoding makes the result more compatible, but it takes time and introduces some compression loss. The original frame dimensions and frame rate are retained unless the source requires a compatibility adjustment.
- Output container
- MPEG-4
- Video / audio
- H.264 / AAC
- Best for
- Browsers, phones, and sharing
How to convert AVI to MP4
- 1
Choose one AVI video up to 100 MB.
- 2
Select an output quality and start the local browser conversion.
- 3
Preview and download the converted .mp4 file.
Frequently asked questions
Why is my converted MP4 smaller than the AVI?
Many AVI files use older, less efficient codecs. H.264 can store similar-looking video in fewer bytes, although the exact result depends on the source and quality setting.
Is this AVI to MP4 converter private?
Yes. The video is processed by WebAssembly inside your browser and is not uploaded to Free2Convert. Closing or refreshing the tab removes the working data.
Why can browser video conversion take several minutes?
Video decoding and encoding require substantial CPU and memory. Speed depends on the video duration, resolution, source codec, quality setting, and your device.