Key difference: MOV and AVI are two different types of container files. As the name suggests, container files are files that are used to contain something usually a video and/or audio. Most people do not realize that AVI and MOV are not encoding formats, but are wrappers for formatted video files. Essentially, the main difference between the two is that a MOV file was first used only by Apple computers, while AVI was used by Windows. Essentially, the differences between the AVI and MOV files arise depending on the codecs used.

MOV and AVI are two different types of container files. As the name suggests, container files are files that are used to contain something usually a video and/or audio. Most people do not realize that AVI and MOV are not encoding formats, but are wrappers for formatted video files.

A container file specifies how the data streams inside it are organized. The actual organization and representation of the data streams are done by the various types of codecs. It is the codecs that affects video quality and compression. It describes how video or audio data is to be compressed and decompressed. Hence, a MOV file and an AVI file will differ only on the basis of which codec is used. In fact, they will be almost exactly the same, if the same codec is used in both the file types.

Essentially, the main difference between the two is that a MOV file was first used only by Apple computers, but then was later capable of running on a Windows PC. Similarly, AVI was a Windows rendition of a MOV file. Now, these container files, as well as others, are capable of running on nearly all types of computers.

A .mov file is essentially a QuickTime file. It was introduced by Apple Computer in 1991. It was the first real successful multimedia format. QuickTime was quite advanced for the time. It supported any amount of streams and multi-segmented files. It allowed a user to watch videos on the computer, which was then a fairly new concept.

In reprisal, Microsoft released the .avi file within the following year. AVI stands for Audio Video Interleave. It was included as part of the Video for Windows technology. Similar to MOV, it contained both audio and video data in a file container, which allowed for synchronous audio-with-video playback. However, at the time, AVI did not have the sophistication of QuickTime, nor its advanced features. Later, Microsoft opened the format to OpenDML group to develop it. Eventually, Microsoft dropped the AVI format in favor of their WMV format. AVI, in turn, later became the format of choice for pirated movies, probably due to the simplicity of the program.

Essentially, the differences between the AVI and MOV files arise depending on the codecs used. However, generally AVI tends to be larger than most video formats. This is mainly due to minimal compression features available. MOV, on the other hand, have more compression options available for use through different codecs, hence it is often smaller in size.

Also, depending on the codecs, an AVI file may support multiple video or audio streams. MOV files are also capable of this and are also able to overlay subtitles on the main video stream.

Currently, AVI is the most popular and commonly used file format. It is supported by many video players, as well as some mobile devices. MOV, on the other hand, is still mainly used by Mac users. It is generally not used as commonly as AVI in non Apple users. 

Image Courtesy: iconhot.com, whatthetech.com