A Micro SD card is a super-tiny removable memory card which is designated to store various types of media contents such as music, pictures, videos or even software, etc.

M4V is a standard file container designed to be used for video websites and portable media devices such as iPod, iPhone, iTunes, etc.

As its name suggests, high-definition video (HD video) usually refers to the video which has got high resolution such as 1280×720 pixels (720p) or 1920×1080 pixels (1080i/1080p).