Is a format of audio/video data, which is the most popular today. It can contain files encoded by different codecs, but they will be played in sync and create a unified image to the end user. AVI container supports function in multi-threaded mode, and allows different ratios of audio and video codecs.
Is a video format similar to MP4. The difference between the formats is their developers and protection. Apple company, has developed a format that has provided DRM-lock for M4V. Video files in this format are downloaded from iTunes.