Video glasses tend to come with ridiculous claims about how large a screen they can trick your brain into believing you're watching. However, these claims are often so out of sync with people's perception of the resulting image, they're largely unhelpful. The Epson Moverio BT-100 claim a 320in experience, from 20 metres away.
The image they actually create covers less than a third of your field of vision. This is not IMAX, but once your eyes relax into the image, it's easy enough to compare the experience to watching a 42in TV from 2 metres away - or perhaps a smaller cinema screen, from the back row.
The perception of size also depends on the surface behind the viewing area - the half-mirror layer the image appears on is translucent, so your eyes still perceive the distance to the background. Epson says this will help to alleviate the headaches and nausea that occluding video glasses can cause. We experienced no such feelings with 2D content, so perhaps they're onto something.
The Epson Moverio BT-100 use tiny little TFT LCD panels mounted in the arms of the glasses, which explains why they're so wide. Their images are then bounced through to your eyes, via the half-mirror layer. Epson offers its own diagram to explain how they work -
These panels aren't HD, supplying a total 960x540 resolution. This is known as qHD, or quarter-HD, halving both the horizontal and vertical resolution of 1080p, Full HD. Given several phones now beat this resolution, and that the Sony HMZ-T1 headset is 720p (1,280 x 720), you arguably have a right to be underwhelmed.
However, the image quality produced is respectable. As long as you don't max-out the brightness, which is a requirement in well-lit conditions, contrast and black levels are good. Colour reproduction is fairly impressive too, far surpassing previous video glasses we've tried. A keen eye can tell the display is not HD, but it has enough pixels to do justice to films and offer far better picture quality than you'd see from the little display crammed into the back of the seat in-front, during a flight.
3D performance is less impressive. It only supports the side-by-side 3D format, and there's not a great sense of depth to the effect. The implementation of 3D is very poor in general. There's a 2D/3D button on the control unit that switches between the modes regardless of whether you're watching 3D content or not, completely distorting the UI or 2D video if you press it accidentally. This is a case of the hardware side of the Moverio BT-100 not fitting into the Android 2.2 software side well enough.
The problem is that Epson hasn't done a great deal to Android 2.2 FroYo to turn it from a smartphone system into one suitable for video glasses. Perhaps the most crucial knock-on effect of this is that video codec support can be charitably described as remedial.
You're one button press away from the standard Android home screen
Without packing any support in beyond the Android basics of H.264 and MP4, most people's video libraries will simply refuse to play here. All of the popular online video formats - Divx, XviD, MKV - refused to play natively. Only by installing a third-party video player app, which took some effort, were we able to get other files running. And then we were disappointed by what the Moverio BT-100 was able to handle, given it runs a dual-core 1GHz Cortex A9 processor.
HD files stumbled continually in unwatchable fashion, although at least most SD-quality content is able to play at full speed. With a similar CPU, we'd expect a tablet or smartphone to be able to at least manage 720p files.
Epson does not include any software to transfer or transcode video to the Moverio BT-100, but Android makes transferral simple. Plug a computer-connected USB cable into the microUSB slot of the control unit and an on-screen prompt asks if you want to enter mass storage mode. This makes the internal memory appear as a disk drive, allowing drag and drop file transfer.
Need to convert videos? Plenty of software is available online, both free and paid-for, but not catering for this adds to the conspicuous lack of luxury in the Moverio BT-100 experience. This is not good news when the archetypal buyer - the cash-rich, time-poor business traveller - is unlikely to have much patience for such irritations