Why audio beats video

The failure of mobile videoconferencing has saved users from a lot of frustration and pain

You’ll have noticed, perhaps, that video conferencing by mobile phone is not a routine business tool. But why not? Five years back, a new codec was released by the International Telecommunication Union, which was expected to trigger just this breakthrough.

It’s not apparent either why a random scribble might be interpreted by a computer as an actual word – but you can do it if you have a Tablet. One such squiggle test was converted to Ascii as “boobbrain”, as reported in IT Week five years ago – yes, when tablets were all the rage, people used to do these tests just for fun.

Frankly looking back, I’m more surprised by the failure of scribble analysis, than by the failure of phone videoconferencing.

The great hopes were based on the assumption that “if you can get video across low-bandwidth links, people will love it. Achieving a royalty-free baseline is probably more important than the excellent technology”, Bill Pechey wrote of the H.264 video compression standard. What turned out to be more important than those things were low latency and lip-synch.

The simple fact of the matter is that audio alone is easier to understand than a video call where the movement of the speaker’s face distracts from the voice. Two main problems seem to confuse the listener: delays of more than half a second between the sound and image are very hard to cope with, and an indistinct image of the mouth can also be very offputting.

We’ve all watched BBC News experiment with video calls over low-bandwidth and it hasn’t been very successful: a still photo of the reporter plus a standard phone link usually works much better. And equally, we’ve watched the mobile phone market flood users with twin-camera video phones, which absolutely nobody uses, even one-to-one.

Even though hands-free phones make you look like an idiot walking down the street talking to yourself, people are prepared to endure that, because they serve a practical purpose. No such incentive exists for video calls, and walking into lamp-posts because you’re staring at the screen is a strong disincentive.