Example for Checkpoint
1.3 - continued

However, since there are currently no user agents that can automatically read and speak written descriptions, a multimedia presentation must be accompanied by an audio track which describes important information presented in the visual track. The next example (Checkpoint 1.4) explains the need to synchronize all the equivalent alternatives of a multimedia presentation.

At present there are three formats or languages that support the addition of a separate audio description track. These are Apple's QuickTime, the W3C's SMIL (Synchronized Multimedia Integration Language) and Microsoft's SAMI. You will need different software to play the different formats, so check the multimedia software page to download what's appropriate. From the multimedia software page, we provide links to examples that demonstrate the auditory description track.