AVI File Format (Audio Video Interleave)
AVI (Audio Video Interleave) is a multimedia container format introduced by Microsoft in 1992 as part of the Video for Windows technology. It was one of the first widely adopted video formats for personal computers. AVI stores video and audio data in interleaved chunks, allowing synchronized playback. The format can contain virtually any combination of video and audio codecs, from uncompressed video to DivX, Xvid, and H.264. While AVI has largely been superseded by MP4 for consumer use, it remains common in legacy media libraries, surveillance camera systems, and certain professional video workflows where raw or minimally compressed video is preferred.
Quick Facts
- Extension: .avi
- MIME Type: video/x-msvideo
- Category: video
Advantages
- Simple container format that is easy to work with
- Supports uncompressed video for maximum quality
- Wide codec compatibility
- Good support in legacy Windows applications
- Straightforward interleaved data structure
Disadvantages
- Large file sizes compared to modern containers
- Poor streaming support (no native progressive download)
- Limited subtitle and chapter support
- No native variable bitrate support in original spec
- Mostly obsolete for consumer video distribution
Common Use Cases
- Legacy video archive playback and conversion
- Surveillance camera recordings
- Uncompressed video capture for editing
- Compatibility with older Windows applications
- DivX and Xvid video library management
Technical Details
AVI uses the RIFF (Resource Interchange File Format) container, with data organized into chunks identified by four-character codes (FOURCCs). The "hdrl" chunk contains headers with stream format info, while "movi" contains interleaved audio and video chunks. An optional "idx1" index chunk enables seeking. OpenDML (AVI 2.0) extended the format beyond the original 2 GB file size limit. AVI interleaves audio and video frames in sequential chunks, which simplifies playback but makes editing and streaming less efficient than modern container formats.
Frequently Asked Questions about AVI
Is AVI still used?
AVI is rare in new content creation but still encountered in legacy libraries, surveillance systems, and some professional workflows. Converting AVI to MP4 is recommended for modern use.
Why are AVI files so large?
AVI files using older codecs (DivX, Xvid) or uncompressed video are significantly larger than MP4 with H.264. The container itself has more overhead than modern formats.
Can I play AVI files on my phone?
Most modern smartphones do not natively play AVI. Convert to MP4 for universal mobile playback.
How do I convert AVI to MP4?
FileChange converts AVI to MP4 using FFmpeg.wasm in your browser. The video is re-encoded with H.264 and AAC for maximum compatibility.