Online audio description – 5 tips for best practice

Audio Description (AD) in video content has proved vital for ensuring that people who are blind or vision impaired can experience video presentations such as movies and TV shows. In Australia, AD content is growing in the areas of cinema and DVD. Internationally, we have seen huge growth in audio described television. However AD content still has a fairly low profile online. 

The good news is that in recent times there have been a lot more discussions about AD, including a number of great email conversations relating to techniques and best practice in a number of W3C working groups.

The challenge though is that it is hard to know the best way to go about audio describing online video; while WCAG Level ‘AA’ compliance requires AD, developers have many questions which are not clearly defined. The questions I’ve been asked and have seen online generally fall under the following four questions:   

  • What does AD mean in terms of WCAG 2.0? It is difficult to understand what needs to be done between level ‘A’ and ‘AA’. 
  • What should I do when there’s no room for audio description, such as a talking head?
  • Should I embed two audio tracks or have two separate video files?
  •  Audio description usage online seems to be a bit like the Yeti: I hear about it but I never come across it. Do I really have to do it?

This month’s column will focus on addressing these questions, and providing you wish some quick tips on how to ensure that your video is compliant with WCAG while making sure that people who are blind or vision impaired can enjoy the time-based media content.

Tip 1: Audio description in Level ‘A’ can be a text description

WCAG 2.0 has two different success criteria for audio description, depending on whether you are trying to achieve ‘A’ or ‘AA’ compliance.  Level ‘A’ states that:

1.2.3 Audio Description or Media Alternative (Prerecorded):An alternative for time-based media or audio description of the prerecordedvideo content is provided for synchronized media, except when the media is a media alternative for text and is clearly labelled as such.

What this means is that there needs to be an alternative, but it doesn’t have to be actual AD. An alternative could be a text transcript located on the same webpage as the video content, describing the visual aspects of the video. However, if it is possible to provide traditional AD then the W3C encourages you to do so. 

Tip 2: Level ‘AA’ websites really do need audio described video

Many people argue that there’s no need for audio described content as there’s hardly any out there. 

The WCAG 2.0 Level ‘AA’ guidelines state that:

1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media. (Level AA)

This guideline is pretty clear: audio description really does need to be included for a website to be truly Level ‘AA’ compliant.

The questions then is why, if so many websites aim for Level ‘AA’ compliance, isn’t there more AD video content? Some organisations argue that it’s too hard to do. This appears to be view held by the Queensland state government, that even taken the extraordinary step of removing AD from its policies but including all other aspects of WCAG 2.0 Level ‘AA’.  In practice though it's not as challenging as it first appears, and some of the other tips here can help.

Tip 3: If there’s no room for audio description during the video, put context AD in at the beginning

There’s been a lot of discussion recently about what to do if there’s a video featuring a ‘talking head’. For example, if a government Minister is giving a speech about something which has a lot of talking and no breaks.  Some have argued that a bit of alternative text about the speech located near the video negates the need for AD, while others argue that this does not work as if the video is embedded somewhere else, the text description is lost. Others argue that there’s no real need for AD in these circumstances, but this raises concern among people who are blind or vision impaired who argue that they need some context for the speech.

A possible solution is to put a bit of AD at the start of the video, explaining the context of the speech, the location of the speech, the person talking and any other important information relevant to the event.  This would effectively set the scene for someone who is vision impaired, would require very little effort, almost no additional editing and ensures Level ‘AA’ compliance.

Tip 4: Put a standard version and an AD version online together rather than trying to embed multiple audio tracks

In the case of a talking head, it would make sense just to have the audio described version but in more standard AD video releases such as a movie or TV show, it’s good for people to have the option of viewing the standard version or an AD version.  Many developers have asked if it’s better to try and put multiple audio tracks into one video file or have two separate video files and my advice would be to have two separate versions: while multiple audio tracks work well on DVD, and most online video formats support multiple audio tracks, the time and effort involved in trying to get everything synchronised and ensuring that people have a media player that supports toggling between tracks makes it very difficult.  A great example of best practice on this is the BBC iPlayer. The BBC iPlayer has nearly all of its television programs audio described, and just has an additional AD copy of the show on their website, along with the standard audio version.  This approach works well and due to the low cost of data storage these days, hardly makes any difference to the bottom line on that front. The amount of AD present on the BBC network dispels the myth that there is no AD content available on the web.

Tip 5: there may be an AD soundtrack available already

When it comes to online content, people often assume that there’s no AD soundtrack for the video footage being used even though the footage may have been in the cinema or released on DVD.  It may save you time and effort to track down an AD version of the footage you need to use rather than create an AD soundtrack.

So while AD may require a bit more planning that some of the other WCAG 2.0 guidelines, it may not be as difficult as first though and it will make a big difference in accessibility for people who are blind or vision impaired.  Additional information is also available on creating audio description files.

Dr Scott Hollier represents Media Access Australia on the W3C Advisory Committee and publishes the W3C Column monthly.

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Tags: W3C, Web