FastlyConvert Logo FastlyConvert
workspace_premiumUpgrade Pro
Select Language
videocam Free Online Converter

AVI to MP4 Converter

Convert legacy AVI video files to the modern, universally compatible MP4 format. AVI files often require special codecs and won't play on many devices; our converter ensures broad playback while significantly reducing file size without quality loss, ideal for sharing and archiving.

check_circleNo Watermark check_circleSmaller File Size check_circleUniversal Playback
video_file

Drop your AVI file here

or click to select file

Supports AVI files - Max 500MB (Pro: 2GB)

Why Convert AVI to MP4?

AVI was the dominant video format of the early 2000s, but modern devices and platforms have moved to MP4.

compress

80% Smaller Files

AVI's legacy codecs like DivX and Xvid waste storage compared to MP4's H.264 encoder. A 2GB AVI movie typically shrinks to 400-600MB as MP4 with no visible quality loss, thanks to modern inter-frame compression and entropy coding.

devices

Play on Any Device

AVI requires codec packs on many devices - smartphones, tablets, and smart TVs often can't decode DivX or Xvid natively. MP4 with H.264 is universally supported from iPhones to Android, Roku to PlayStation, with zero extra software.

upload

Stream & Share Instantly

Social media platforms, cloud storage services, and messaging apps all prefer MP4. AVI files are often rejected by YouTube, Instagram, and WhatsApp due to unsupported codecs or excessive file sizes. MP4 uploads faster and streams smoothly.

How to Convert AVI to MP4

1

Upload AVI File

Drag your AVI file into the upload area or click to browse your computer. We accept AVI files encoded with any codec - DivX, Xvid, MJPEG, or uncompressed. Maximum file size is 500MB for free users, 2GB for Pro.

2

Choose Settings

Select your preferred output quality. High Quality preserves the original resolution and bitrate. Balanced reduces file size by 40% with minimal visual impact. Compressed creates the smallest file for quick sharing via email or messaging apps.

3

Download MP4

Our cloud servers transcode your AVI using hardware-accelerated H.264 encoding. Download the MP4 file when complete - it plays on every device, uploads to any platform, and takes a fraction of the original storage space.

More Video Conversions

Explore our other video conversion tools

videocam MKV to MP4

Convert MKV to MP4
videocam WebM to MP4

Convert WebM to MP4
videocam MOV to MP4

Convert MOV to MP4
gif MP4 to GIF

Create GIFs from videos

Frequently Asked Questions

Common questions about AVI to MP4 conversion.

What is the AVI format and why is it still used?

expand_more

AVI (Audio Video Interleave) was introduced by Microsoft in November 1992 as part of its Video for Windows technology. It became the dominant video format through the late 1990s and 2000s, especially during the DivX/Xvid era when people ripped DVDs to AVI files. Many users still have large AVI collections from this period, and some professional cameras and screen recording software still output AVI due to its simplicity and low processing overhead.

Does AVI to MP4 conversion remove metadata?

expand_more

Basic metadata like duration, resolution, and codec information is preserved in the MP4 container. However, some AVI-specific metadata fields may not have direct MP4 equivalents. If your AVI contains chapter markers or custom tags, those might not transfer. Standard video and audio stream properties are always maintained.

Can I convert AVI files with multiple audio tracks?

expand_more

Our converter processes the primary audio track by default, encoding it as AAC in the MP4 container. AVI files sometimes contain multiple audio streams (e.g., different languages). The primary audio track is always converted. Pro users can select which audio track to include in the output MP4.

Why does my AVI file play with no audio?

expand_more

AVI files sometimes use older audio codecs like AC3, DTS, or MP2 that aren't supported by all media players. Converting to MP4 transcodes the audio to AAC - a universally supported codec - which resolves playback issues. If the original AVI truly has no audio stream, the MP4 output will also be silent.

Is AVI better quality than MP4?

expand_more

Not inherently. Quality depends on the codec and bitrate, not the container format. An AVI file using the DivX codec at 1500 kbps will look identical to an MP4 file using H.264 at 1500 kbps - but H.264 typically looks better at the same bitrate due to more advanced compression algorithms. Uncompressed AVI preserves every pixel, but produces enormous files impractical for most uses.

Can I batch convert multiple AVI files?

expand_more

Currently, our online converter handles one file at a time for optimal quality and performance. If you have a large collection of AVI files to convert, process them sequentially - each conversion takes only a few minutes. Pro users benefit from faster processing speeds and larger file size limits.

The History and Legacy of the AVI Format

Microsoft introduced AVI (Audio Video Interleave) in November 1992 as the default video format for Windows 3.1's Video for Windows framework. The format was groundbreaking for its era - it could store synchronized audio and video data in a single file using an interleaved stream architecture, where audio and video chunks alternate in the file for smoother playback on the limited hardware of early PCs. AVI's RIFF (Resource Interchange File Format) container was simple by design, prioritizing compatibility over features.

AVI reached peak popularity during the DivX and Xvid era of 2001-2008, when it became the de facto format for video distribution on early file-sharing networks and burned DVDs. The codec-agnostic nature of AVI meant any video codec could be wrapped inside it, but this flexibility became a liability - viewers often encountered "codec not found" errors because AVI files didn't embed codec information the way modern containers do. Users had to install codec packs like K-Lite or ffdshow to play downloaded AVI files.

Today, AVI has been largely superseded by MP4 (MPEG-4 Part 14), which offers superior compression ratios through H.264 and H.265 codecs, native subtitle and chapter support, better streaming capabilities, and universal device compatibility. However, AVI persists in niche use cases: some professional video capture software outputs AVI for its low overhead, scientific imaging applications use uncompressed AVI for lossless recording, and millions of personal video libraries still contain AVI files from the 2000s that benefit from conversion to the more efficient MP4 format.

Privacy & Security

Your videos are processed securely. We take your privacy seriously.

  • check_circleAutomatic Deletion: All uploaded AVI files and converted MP4 files are permanently deleted within 24 hours.
  • check_circleEncrypted Transfer: Files are uploaded and downloaded over HTTPS with TLS 1.3 encryption.
  • check_circleNo Human Access: Conversion is fully automated. No one views, analyzes, or shares your video content.