How to play M4V format files?

What is .m4v - MP4 is a container format. As any other container format like AVI (.avi), RealMedia (.rm, .rmvb), QuickTime (.mov), MPEG (.mpg, .mpeg), Matroska (.mkv, .mka), OGM (.ogm) it allows you to combine different multimedia streams (mostly audio and video) into one single file. And .m4v is .mp4 files with the WRONG extension introduced by Apple for video+audio.

So the .m4v file must be renamed to .mp4 before you play it.

Step 2. Play the new file with iTunes.

1 . Choose file > Add File to Library, or file > Import. Select the renamed file you want to play.

2 . Open the playlist named "recently added" and double click the file.