All relevant information of a audio/video file is stored in the file's header area, including duration, codec id, aspect, frame rate, bit rate, sample rate, channels, bit depth, language, etc. MediaInfo can obtain and utilize these info from the header of a media file with ease, which is very helpful for media software developers. If you just want to know the codec info of some movie or music file that could not be recognized or played correctly, you can use MediaInfo to check its technical & tag data.