You have to make some important decisions when you are adding sound and video. Consideration for your visitors is important! Some visitors might not want to be forced to hear the music that you are playing (if you are using a loop by the author, this is more often the case). Your visitor might be in a public setting that has other music playing already. Because of these reasons, you should at least always offer an "off" button for background sounds. Volume controllers or pause/play toggles also work very well. This kind of responsibility and usability offers a much better experience when someone visits your site.
Because sound and video files are often very large, you should try to communicate how much data need to be transferred to the end user by using something like a progress bar. If the file is large (like our video file), you should give some kind of indication that content is downloading so a visitor doesn't arrive at the page and think nothing is happening. Also, your video might also include an audio track. If so, you should offer the opportunity to control the audio using buttons or sliders.