Microsoft's classic container format for audio and video data
AVI (Audio Video Interleave) is a multimedia container format introduced by Microsoft in 1992 as part of its Video for Windows technology. The format was designed to store both audio and video data in a single file for synchronized playback. Despite its age, AVI remains in use today, particularly for legacy content and specific applications.
As a container format, AVI can support various video and audio compression methods (codecs), making it quite versatile. The format stores data in chunks called "frames," with audio and video data interleaved to facilitate synchronized playback even on systems with limited resources. This interleaving gives the format its name.
While AVI has been largely succeeded by more modern formats like MP4, MKV, and WebM for new content, its simplicity and wide compatibility with legacy systems ensure it maintains relevance in specific scenarios and for archival content from the 1990s and early 2000s.
AVI files are based on the RIFF (Resource Interchange File Format) container architecture, which organizes data into chunks. These chunks contain headers that describe the data and the actual media content. The format's limited metadata capabilities, maximum file size restriction of approximately 4GB (due to 32-bit offset limitations), and lack of native support for advanced features like chapters and multiple subtitle tracks reflect its age. Despite these limitations, AVI's relatively simple structure contributed to its widespread adoption and continued legacy use.
AVI remains important for compatibility with older systems, software, and hardware devices that may not support newer formats. Institutions and businesses with legacy equipment, such as older industrial systems, medical devices, or specialized hardware from the 1990s and early 2000s, often continue to use AVI. The format's long-standing presence means that even systems with minimal multimedia capabilities can typically handle AVI files.
Many security and CCTV systems use AVI as their recording format due to its simplicity and reliability. The format's basic structure makes it well-suited for continuous recording applications where files may need to be split into manageable chunks. Its compatibility with a wide range of playback software also makes it convenient for security applications where footage may need to be reviewed on various systems.
Educational institutions and archives with video content from the 1990s and early 2000s often maintain AVI files. While migration to newer formats is increasingly common, many older educational videos and archived media remain in AVI format. The format's stability and wide compatibility make it suitable for preserving access to older content without immediate need for conversion.
Some video editing workflows, particularly those involving older software or simpler editing requirements, still utilize AVI. The format's frame-based structure makes it suitable for frame-accurate editing, and its support for both compressed and uncompressed video provides flexibility. While professional environments have largely moved to more advanced formats, AVI remains relevant in basic editing scenarios and educational contexts.
Various scientific and technical applications continue to use AVI, particularly for visualizing data, recording experimental results, or documenting procedures. In fields like microscopy, medical imaging, and industrial testing, AVI's simplicity and broad compatibility make it a practical choice. Many specialized scientific instruments and software packages default to AVI output due to its established position and reliability.
AVI has strong support across major operating systems:
Most video player applications support AVI:
AVI has mixed support on modern platforms:
AVI can contain various codecs, but compatibility depends on codec support:
| Feature | AVI | MP4 | MKV | MOV | WebM |
|---|---|---|---|---|---|
| Legacy Compatibility | |||||
| Modern Features | |||||
| File Size Limit | |||||
| Multiple Audio Tracks | |||||
| Subtitle Support | |||||
| Web Streaming | |||||
| Mobile Support |
AVI excels in legacy compatibility but falls behind in modern features like multiple audio tracks, extensive subtitles, and large file support. MP4 offers excellent all-around performance with good compatibility and streaming capabilities. MKV provides the most comprehensive feature set but with more limited compatibility. MOV balances features and compatibility with strong Apple ecosystem support. WebM is optimized for web delivery with royalty-free codecs.
When converting from newer formats to AVI for legacy compatibility, carefully select appropriate codecs that your target system supports. For older systems, consider using widely compatible codecs like DivX or XviD for video and MP3 for audio. Be mindful of the 4GB file size limitation - for longer videos, you may need to reduce quality, split the file, or use OpenDML AVI extensions if supported. Tools like HandBrake, FFmpeg, or XMedia Recode offer good control over conversion parameters.
When creating AVI files from raw footage or editing projects, consider your quality requirements versus file size needs. For editing purposes, you might choose lossless or minimally compressed codecs like HuffYUV or uncompressed AVI, though these create very large files. For distribution, more aggressive compression with DivX/XviD or similar codecs is appropriate. Most non-linear editing software can export directly to AVI with various codec options.
Some legacy applications or devices may require specific AVI configurations. For security systems, Motion JPEG (MJPEG) is often preferred. Medical and scientific equipment may require specific codecs or even uncompressed AVI. When converting for these purposes, consult the system documentation and test thoroughly to ensure compatibility. In some cases, you may need to use older conversion software that better matches the expectations of legacy systems.
Converting AVI to MP4 with H.264 encoding is one of the most common conversions for modernizing content. This dramatically improves compatibility with modern devices, reduces file size, and enables web streaming. Use software like HandBrake, Adobe Media Encoder, or FFmpeg for best results. When quality is important, use two-pass encoding with an appropriate bitrate for your content. For most content, the H.264 "High" profile with AAC audio offers the best balance of quality and compatibility.
When converting AVI for mobile playback, consider the target device's capabilities. For iOS devices, MP4 with H.264 video and AAC audio is ideal. Android has similar preferences but may support a wider range of formats. Adjust resolution to match the device's screen size - no need to keep 1080p for a small phone screen. Many conversion tools offer device presets that automatically configure appropriate settings for specific mobile targets.
AVI is poorly suited for direct web playback. Convert to web-friendly formats like MP4, WebM, or HLS (HTTP Live Streaming) format. For the best cross-browser compatibility, provide both MP4 (H.264) and WebM versions. Set appropriate bitrates for streaming - typically 2-5 Mbps for 1080p content intended for broadband connections, with lower bitrates for mobile-targeted versions. Video hosting services usually handle this conversion automatically.