AVItools is an application for Mac OS X used for creating and editing videos AVI. It is a branch of another application called MKVtools, so if you are familiar with its operation, it should be comfortable using AVItools. As its name might imply, AVItools is a graphical interface for a variety of useful tools for processing video files. Mplayer mencoder and do most of the work. Limitations on AVItools capacity ‘are most often due to limitations with these applications.
When you open a video file in AVItools, you will be presented with a list of video, audio and subtitle tracks contained in the file. Sometimes there will be enough information for you to determine what each track. If not, you can select a video and an audio track (and optionally a subtitle track) to preview the tracks in an mplayer window.
Once you have determined what tracks you are interested, you can convert tracks into a video AVI, or you can extract the tracks individually to manipulate in your favorite video application. You can also edit AVI files either splitting or joining videos.