Browsers are typically only capable of displaying jpg, png, and gif photos, as well as any flash-based video. They are not natively capable of displaying .bmp, or playing music/other video.
To solve this, you use third party addons. For playing music, you could add a simple <embed> tag which would typically bring up Quicktime to the user, or use this:
http://mediaplayer.yahoo.com/As for video, there's no easy way to embed. Using the <embed> or <object> tags for video will occasionally work with third party plugins on the user side, but only with few file types and often only after downloading the entire file (slow). Without coding your own player, the only way I see this happening is to convert ALL of your video to flash (*.swf) and then <embed> it into the page.
http://www.w3schools.com/html5/tag_embed.asp