It is important that live audio and video content has a text alternative that adequately describes its purpose. Alternative text acts as a fallback for people who, for whatever reason, cannot see audio and video content. It means that people who are blind or partially-sighted can use assistive technology, such as a screen reader or screen magnifier, to read the text alternative of live audio and video content in much the same way they would read other text content on a webpage. The text alternative may not convey the actual content but it conveys the purpose of the content.
There are various methods of providing alternative text.
To add alternative text to an object element (which is typically used to embed audio and video content, such as Flash or Java), include a paragraph element <p> containing the alternative text within the object element.
Flash, Java and other plug-ins also have their own accessibility options to allow you to specify alternative text descriptions.
HTML5 also has new native <audio> and <video> elements that can make the creation of accessible players much easier. WAI-ARIA also provides ways to describe the purpose of audio and video content by using the "aria-labelledby" by or "aria-describedby" attributes, provided there is an existing inpage description.
//A paragraph element is included within the object element to provide an alternative text description.
<object type="application/x-shockwave-flash" width="600" height="400">
<param name="movie" value="movies/.swf" />
A video of the first manned lunar landings in 1969.<p>
</object>