If you plan on embedding audio and video clips on a webpage, or offering downloads of said files, try to include a transcript of the media as well. This is important for describing the actions (such as "Students sat on the quad.") and sounds ("The family laughs.") depicted in your clip.

There are many outsourcing services available for transcription, which should suffice for basic audio and video.

One of the popular ones is Transcribe.com

Should your recording be more technical, scientific, or legal in nature, consider finding a transcription service provider that specializes in your industry.