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Monday, January 31, 2011

The Ten Challenges of Mobile Video

By Jonathan Rosenberg, Chief Technology Strategist at Skype

On June 7, 2010, Steve Jobs unveiled the iPhone (News - Alert) 4 to the world. High-definition video recording, a new high-resolution display, a new form factor, and a front-facing camera were some of the new features. However, the feature that gained the most attention was the announcement of Facetime, a video calling feature integrated into iPhone 4. Facetime enables one-to-one video calling between iPhone users with just the single touch of a button. It renders in full screen, and enables the user to send video using either the front or rear-facing cameras (for a see-what-I-see experience).

Reactions to Facetime were mixed. Some heralded it as the arrival of video telephony to mobile. Others saw it as a gimmick. One thing is certain however – Facetime is not the first time a company has attempted to market mobile video telephony. The feature has been around for a while, in fact. European mobile phones with video calling have been available for years. Mobile video telephony was one of the original motivations for 3G investments among mobile operators. However, the feature never took off.

Building a successful mobile video solution requires tackling ten technology challenges:

Limited Front-Facing Cameras

Mobile video requires a front-facing camera to accomplish two-way video chat. This feature is more common outside of the U.S., and is only recently arriving on mobile phones in the U.S. It is possible to provide a “see what I see” feature using the rear-facing camera; this represents a substantially different use case.

Low-Quality Screens

To see the other participant, a large, high-resolution screen is required. Up until the arrival of iPhone and phones with similar form factors, screens have been too small to have a quality video experience.

Limited Networks

Video consumes much more bandwidth than audio. Depending on the size of the screen, continuous bandwidth of between 100knps and 250kbps are typically needed, and even more than that is better. This kind of bandwidth is hard to sustain on wireless networks, and not always available.

Compatibility Challenges

For a video call to work, the other participant needs compatible equipment and software. It can be very difficult for an average user to figure out whether a video call will work, or what to do to make it work. Typically only a small subset of a user’s contacts are reachable on video. This has been especially problematic in solutions that are carrier specific, since users often do not know the mobile operators of their contacts.

Poor Lighting

Good video requires good lighting. This is already problematic in desktop video. In mobile video, where users are under a highly variable set of conditions, and with conditions that change even during the call, the challenges of good lighting are even larger.

Uncentered Video

Users must hold their phones in such a way that the cameras are centered on their faces, and remain centered throughout the calls. This is difficult to do. Since users cannot hold their hands perfectly still there will always be shaking. This reduces the overall quality of the experience.

Discomfort

For calls of any duration, users must hold the cameras at a set distance from their faces, and not change it. This can become uncomfortable after a while. Many users are often uncomfortable with video in general, and don’t want to be seen all of the time.

Limited Use Cases

Mobile phones are often used in cases in which users are wearing Bluetooth headsets and doing something else with their hands. Driving and eating are two examples. Since mobile video requires users to hold the phone, video calls are not possible in these cases.

Insufficient CPU

Decoding and encoding of video are CPU-intensive operations. Many phones do not have sufficient horsepower to run two-way video, especially with the level of quality required. This problem is getting addressed through the natural evolution of mobile CPUs, and is also getting addressed by the presence of dedicated DSPs, which can do the encoding and decoding in hardware.

Poor UI

Video must be easy to use. Many video solutions in the past have had complex UIs that were difficult for the average user to navigate.

These challenges fit into several categories. Some of them are hardware-oriented (limited front-facing cameras, insufficient CPU, low-quality screens), and can be addressed by changes in hardware. Some of them are software-related (compatibility challenges, poor UI), and can be addressed by improvements in software. Others are more fundamental (poor lighting, discomfort), and solutions may be possible through innovation.

Unfortunately, there is no public data available on the usage of Facetime. Whether it has adequately addressed all of these technical challenges to gain market traction, only the future will tell.


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