M4V is a video file format that has been downloaded from the Apple iTunes store. The format contains TV shows, videos, films, music. It looks like a .MP4 file, but it sometimes has copy protection when Apple's FairPlay DRM is used (technical copyright protection). The M4V format, i.e., MPEG-4 iTunes Video File, was developed by Apple. MP4 is a container format. Like the same formats as MOV, AVI, MKV, it provides the ability to combine a variety of multimedia streams into one file. Mostly it is audio and video. In order to play the protected M4V file, the computer must be authorized using the iTunes account from which the videos were purchased. In this case, it can be used in order to buy video. Unprotected M4V files can be played by other video players if the extension is changed from .M4v to .Mp4. Files with the M4V extension contain both sound and video data. You can convert M4V files to MP4 format. In this case, it will be possible to play them on other computers, since the M4V files are protected by DRM. MP4 files, compared to the M4V format, do not allow you to specify partition information.
F4V is a well-known flash video format developed by Adobe System. It is supported by Adobe Flash Player. Currently, approximately 80% of online videos are transmitted using Adobe Flash technology. Files with the F4V extension are called a container format. The F4V format, in comparison with other files of the FLV category, uses boxes to store information. In addition to devices with an operating system from Apple, these files can play almost all browsers that support flash video playback. F4V files resemble .FLV files, but use “blocks” to store data. Examples of blocks that are supported by the F4V format include meta block (metadata), moov block (file header), ftyp block (requested player tools), uda block (user data in free form), etc. The format container, in the development of which the ISO Media File Format was used, initially used the Quick Time Container Format from Apple. Compared to the old FLV format, the F4V format is fully compatible with the h.264 and ACC formats. This provides an opportunity to use other container formats.