I believe that there are two good reasons why Apple might have chosen to provide the FaceTime video chat application over Wi-Fi only:
- 1.Video chat is possible over a 3G connection, but is inherently limited to a low bitrate by the nature of the 3G network
- 2.In contrast to 3G networks, IP networks are ubiquitous
A video call on a 3G mobile network provides a low bandwidth for the video, so that careful choice of frame rate and resolution is needed to keep within the constraints. When 3G video capable devices were first introduced, screen sizes and the resolutions possible over the network were well matched. Reasonable video quality (QCIF, 176x144 pixels) could be achieved, despite 3G bandwidth restrictions. However, mobile device technology has moved on - would someone spending £500 on an iPhone 4 with its large, high resolution screen and fast processor be happy with a video chat feature that couldn't make use of the full screen? - probably not, especially if they were paying for the video call.
3G video, based on the 3G-324M protocol, may be past its sell by date - but fear not, IP-based video communications is a viable alternative, and 4G networks (that use IP technology at their core) are around the corner.
My second point is that, at least for paid-for applications, you would want to be able to make video calls, perhaps conference calls, with a multitude of end-points:
- Other users on mobile devices
- Office-based users at their desks (using PC-based video communications software or a device such as the just announced Cisco Cius
- And perhaps to your corporate video conferencing suite where you would be conferenced with a team of people using life size telepresence equipment
So I believe Apple got it right - while it may seem limiting to only allow Wi-Fi connected video calls at present, it was done for good reasons. And it is hopefully going to be the push up the PLC curve for video communications that we have all been waiting for - we just need to keep up the momentum!