Is a multimedia container format from Microsoft, which stores video and audio file streams. Distinctive feature is a the lack of information on the coding data. The container defines the structure of the stream so it can, like AVI, contain videos with different codecs, as well as operate during synchronization of streams.
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.