Virtualisation of Display Graphics

Apreso can potentially capitalise on the technology trend towards virtualisation of display graphics. This virtualisation is being driven by VNC products such as RealVNC and Glance.

What's VNC? Well, a good definition is provided by Robin Good (no pun intended): "VNC is, in essence, a remote display system which allows you to view a computing 'desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures."

Whereas a display connection used to be a hard-wired analog link between a computer and a monitor, it is now possible to transmit display graphics digitally (using DVI and DisplayPort) and wirelessly over a LAN. Indeed, many modern projectors support wireless operation and a 'meeting mode' where learners can view the presenter's desktop.

The current Apreso product offering relies on either local screen capture or a hardware interface from UK-based Datapath. The Datapath Vision RGB Pro capture card converts analog VGA signals to a digital stream that Apreso converts to Flash. This works fine for desktop capture stations, but does not allow remote screen capture on laptops. One can use an external VGA-to-USB converter to interface a laptop, but the results were in my experience not acceptable (I used the Epiphan product, but did not try the Pro version).

Eventually, I found a solution that works. Using an inexpensive VNC software product known as Atelier Web Remote Commander, it is possible to monitor a remote screen over a wired or wireless LAN connection. The image quality is identical to what is seen by the presenter and the in-room audience (there is no analog conversion to VGA), and is thus superior to what can be captured using a Datapath card. Using AWRC, the remote desktop image can be enlarged to full screen view and then captured using Apreso's local screen recording capability. This works on laptops, making Apreso a mobile capture solution.

The problem with this approach is that the capture station operator is 'flying blind'. Because the remote image fills the local screen, the operator cannot check audio levels, video quality, or system status. It is likely that this issue can only be addressed with the next generation of video drivers that support display graphics. Today you can already use Windows Media encoder to capture the screen display, and minimise the encoder during processing. But it will take some time before 3rd party applications like Apreso can record a remote screen without simultaneously displaying it.

Incidentally, remote screen recording using anything but Datapath cards is not supported by Anystream. Hopefully the folks at Anystream will lobby Microsoft to provide more flexible VNC display drivers, and will provide alternatives for recording display graphics that do not rely exclusively on Datapath hardware.