Audio Description - Embracing the Next Generation of Audio

Guest blog by John Paton, Innovations and Technology Officer at RNIB

The use of immersive sound technology has revolutionised the cinema experience making films feel more real than ever before. Immersive sound brings audio to life with a soundtrack that surrounds and envelops the user for better realism and a more powerful entertainment experience. Dolby Atmos is just one form of NGA (Next Generation Audio) doing this, and the possibilities extend far beyond better sound at the cinema.

From channels to objects

The channel-based audio we are all familiar with (mono, stereo, 5.1 sound, etc) divides the sound between the speakers, as long as you have the right number of speakers for the channels. 

Object based audio, such as Dolby Atmos, separates the various sounds you should be hearing into chunks, called objects, and says when and where you should hear them. If you hear a car horn in the street-scene of a movie, object based audio delivers the sound of a car horn, the 3D coordinates where and when it should be heard and your sound system delivers it using the speaker system - so you hear the car horn in the right time and place.

Object based audio can even be used to create a 3D effect using headphones. When a sound comes into your ears the crinkles of your outer ears create “echoes” and “fades” to work out the direction the sound is coming from. These echoes and fades can be synthesised in software to deliver a 3D sound through your headphones. 

This creates some interesting questions. If you could place the audio description anywhere around the user where do you put it? Should it come from the direction of the action it’s describing, almost as if a friend is describing the program or should it appear to come from everywhere at once, like a narrator outside the story. 

Personalised audio

Object Based Audio can increase the choice for the user too.  Labels called metadata are added to chunks of audio allowing sounds to be treated more individually. This means you can decide which ones to hear. So instead of sending two full soundtracks for a program; one version with and one without audio description, you can simply just send one stream and decide whether to play the objects with audio description or not. For people who struggle to hear dialogue amid sound effects and background music, the speech volume could also be boosted separately and everything else faded. This is often referred to as ‘clear speech’.

The possibilities extend beyond improving accessibility too, such as alternative languages could be delivered together or even home or away team commentary on football matches. The user can then just choose which to listen to. It could even turn any music video into a karaoke opportunity by letting you mute the singer or any of the instruments.

Simply better sound

Improved surround sound could bring benefits to blind and partially sighted people just on the virtue of sounding better. Television technology has been getting bigger screens, sharper pictures, blacker blacks and more colourful colours but often users are stuck with just standard stereo sound. By upgrading the listening experience blind and partially sighted people can share in the technology revolution happening. By using well placed audio cues there may even be a reduced need for audio description. TV drama could be more like radio plays that just happen to have video accompanying them. 

What’s next?

From personalised audio, clear speech and better integrated audio description to just better sounding audio it’s clear that next generation audio will make a huge difference. The technology is still developing and  so it will take a while for this to find its way into TVs. In the meantime, RNIB is exploring the different ways next generation audio could help blind and partially sighted people through projects such as ImAc. When broadcasters are ready to take advantage of next generation audio we’ll be there to advise them on behalf of our members.
 

RNIB at TechShare Pro

Don't miss the Audio Description and Video On Demand session at TechShare Pro, chaired by RNIB's Sonali Rai on Thursday 21st November at 12.45PM on our Day 2 Live Stream.