When we consider providing audio description for web based media, we understand it to be broadcast alongside the primary audio and video of the media when it is activated. Standard description in this way is ‘closed’ and applied to post-production content. However, new forms of description and new ways to provide them are emerging and it's important to understand that not all web based media description is the same.
Taking AMI-tv and the newly licensed AMI-tv French as the first example, the described programming content on these stations is ‘open’. That means that the audio description track and the primary audio are the same, allowing for straightforward throughput of accessible web based media. When description is ‘open’, the audio for the description will still have been applied in post-production. The audio tracks are then merged before broadcast. Similarly, embedded description functions in a similar manner, but is produced in a different style.
In the case of embedded description, the program being described is produced while being described. All the elements appearing within the program are described for the viewer as the program progresses through each sequence. In that way the merging of what is otherwise two separate audio tracks is accomplished and broadcast only as the primary track. In the case of providing accessible web based media produced with embedded description, it is then as straightforward as the previous example.
The previous two examples speak to the provision of description through scripting during production or more commonly through post-production. Another form of emerging description though is that of ‘live’ description. Used commonly for the description of major events, sports activities and other live programs, the broadcast of these programs requires the audition of a live describer who has the knowledge to be able to view a program and describe it as it takes place. When this live media is provided in a web based context, the format of how this separate description is to be provided has yet to be defined. The throughput of it though would likely be in a similar fashion to that of the previous two examples as the described audio would overlap the primary audio.
As these emerging types of description continue to evolve, their provision in a web based context will be further defined through the development of standards for each form. The Canadian broadcasting system recently established audio description post-production best practices with consideration for web based media. The next steps in this regard will be to define and examine the requirements for other new forms of emerging description, along with multilingual description requirements.
This is the fifth article in a series on audio description by Robert Pearson, Director of Accessible Digital Media at Accessible Media Inc. (AMI), based in Toronto, Canada. He is also Chair of the Canadian broadcasting industry's Described Video Best Practices (DVBP) Working Group, striving towards the establishment of industry best practices in the area of audio description, known as described video in Canada.