WAV (or WAVE) is actually the first full-fledged audio format with good sound quality. It was developed quite a few years ago by the joint efforts of Microsoft and IBM. Sometimes this format is even called “Audio for Windows,” because it is the standard for storing audio stream for a traditional Windows desktop computer. Full name - Wave Audio File Format. The short name is derived from the English word wave ("wave"). The peculiarity of this format of digitized audio stream is the lack of compression. WAV files take up too much space, but it is ideal for storing high quality files in their original form.
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.