Convert mv4 to pjpeg

What is the difference between .mv4 and .pjpeg?

Description: M4V is a video container that stores audio and video data used for iTunes files. Files of this type may be protected from illegal viewing and copying with Apple FairPlay DRM. In this case audio or video files should be bought in iTunes store. Not protected files can be viewed almost in any modern player because the format is based on MPEG-4 structure.; A PJPEG file is a bitmap image created in the Progressive JPEG format (PJPEG). It contains encoded bitmap data so that the downloaded image appears progressively from a blurry picture to the final sharp image. PJPEG files may also fill alternating horizontal lines until the full picture is revealed.