Multimedia comes in many different formats. It can be almost anything you can hear or see like text, pictures, music, sound, videos, records, films, animations, and more.
On the Internet you can often find multimedia elements embedded in web pages, and modern web browsers have support for a number of multimedia formats.
Audio and video are used for enhancing the experience with Web pages (e.g. audio background) to serving music, family videos, presentations, etc. The Web content accessibility guidelines recommend to always provide alternatives for time-based media, such as captions, descriptions, or sign language.