The Advanced Authoring Format (AAF) is a professional file interchange format designed for the video post-production and authoring environment. It was created by the Advanced Media Workflow Association. The AMWA develops specifications and technologies to facilitate the deployment and operation of efficient media workflows, working closely with standards bodies like the SMPTE.
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.