Executive Overview: Impact of Device Size on Quality of Business Video Conferencing

Executive Overview: Impact of Device Size on Quality of Business Video Conferencing

By Phil Edholm February 19, 2013 Leave a Comment
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Executive Overview: Impact of Device Size on Quality of Business Video Conferencing by Phil Edholm

This is an executive overview with excerpts from a white paper of the same name available on the PKE Consulting web site.

With the advent of video devices moving from large room systems to PCs and onto hand-held devices, there is a significant discussion about how video will be used across these devices. This paper is intended to discuss a critical issue that emerges in this area, that small devices and their cameras are ill suited to business video. This paper will first discuss how business video is used and the requirements for video to be of value and then discuss the physical constraints of devices.

The conclusion is that small device video may be of limited business value, but great social value. While this may not be universal, it does represent a significant set of questions about the value of small device video and whether it will be adopted by business users.

The reason is that, while cameras have a fixed visual angle of about 60 degrees in the wide field, human viewing is also about 50 degrees in the wide field. As business video requires seeing more than just a face to have the true visual impact of the reaction and agreement, the distance the camera needs to be from the user becomes an issue as the device screen shrinks. It is clear that seeing body language and high resolution is important to convey the true visual image, this is why Telepresence has been so popular. However, this is very difficult with small devices. In order for the camera angle to show the body, the device must be so far away that the image on the screen is virtually useless. This first image shows the "ideal" distance for a desktop system with the camera capturing from lower chest to two inches above the head and the display being the ideal 50-degree viewing angle horizontally. While this perfect display is 35 inches, the analysis shows that a 25- or 27-inch display is adequate.

Video Device Graphic 1

However, when the same analysis is applied to a smartphone with a four-inch screen (iPhone, Android device), the same distance is required for the camera to see the entire "ideal" field, but now the screen is incredibly small. The second figure shows the ideal camera angle on the left and the ideal viewing angle on the right. On the left the image on the camera is very small relative to the red lines that define the ideal 50-degree angle (per the SMPTE and the THX standards for video and television). As can be clearly seen, the device is about 10 percent of the ideal width or height, but as this is squared, it is only about one percent of the potential vision field. So if the ideal has a field of 1920x1080 pixels in HD (about 2M), the viewer is only seeing a resolution of 20,000 pixels. Alternatively, by holding the screen close, the screen will fill the visual field, but the resulting camera view is the dreaded "nose hair" video.

The conclusion that small devices probably will not be good for real business video where seeing reactions is critical comes out of this analysis. While this does not preclude the value of video on these devices being used to show a problem such as a flat tire or which fruit to buy, for person-to-person video, small devices are far from ideal. In the paper, charts of acceptable ranges for a variety of devices are presented, along with graphs of acceptable ranges.

Video Device Graphic 2

For the full version of this paper, visit PKE Consulting. 


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