An AVI file is a container from early Windows days under the name Audio Video Interleave, but the compression inside depends on the chosen codecs, so .avi files can vary in behavior because playback success relies on whether your device supports the embedded codecs, explaining no-sound or jittery playback issues; it still shows up in legacy material and DVR footage, even though newer formats like MP4 or MKV yield smaller sizes.
An AVI file appears often on Windows systems ending in “.avi,” with its name—Audio Video Interleave—indicating that audio and video are packaged together, but the real compression depends on whichever format was used inside the container; this is why some .avi files work smoothly and others fail or lack sound when the device can’t decode the internal streams, and although AVI persists in older downloads and CCTV/camera outputs, it’s usually less efficient and less universally supported than MP4 or MKV.
An AVI file acts as a housing for encoded streams rather than a single compression type, because the “.avi” extension simply marks an Audio Video Interleave file that holds one or more video and audio streams, while playback behavior is determined by whatever compression format is stored inside—Xvid, DivX, MJPEG for video or MP3, AC3, PCM for audio—which explains why some AVIs play fine and others refuse to open or lose sound on devices lacking the right codec, proving that the container is just the outer box.
AVI is frequently described as a common format due to its origins in Microsoft’s old video framework, where it debuted as part of Video for Windows and became a standard for older cameras, recorders, editing software, and CCTV/DVR exports; its long legacy means most software can still open AVI today, though newer workflows generally favor MP4 or MKV for broader device support.
When people say “AVI isn’t the compression,” they mean AVI simply stores streams without defining the compression method, leaving that to the internal encoder inside, which can vary from DivX/Xvid to MJPEG or H.264 for video and MP3/AC3/PCM for audio; this is why two AVI files can differ massively in size, quality, and compatibility, with devices supporting AVI only in cases where they also support the specific media formats used, which explains why some AVIs play fine while others show video without sound or fail on smart TVs.
