Scalable video coding
VuCall uses a new technology developed by Vidyo Inc. specifically to manage packet based transmission over the internet. It is based on H.264 Scalable Video Coding (SVC) that Vidyo pioneered with the standards organisations ITU and ISO, and is further optimised by Vidyo’s patented router architecture.
Resilience
When video is transmitted over an IP or 3G network it can suffer from high packet loss due to the underlying “best effort” model of the internet protocol. A major advantage of VuCall’s video internet meeting service is its resilience to packet loss compared to legacy systems.
The following screenshots and video demonstrate the performance of VuCall against legacy technology. They show that even with packet loss of 10 and 20%, VuCall stays resilient, reliable and smooth.
Demonstration
Example video – click to play.
A legacy system with
2% packet loss
VuCall with
2% packet loss
Personalised data stream
VuCall’s technology platform is also adaptive and flexible. Intelligent routers monitor each user’s available processing power, connection speed and quality and constantly optimises the video and audio stream for each user. This means that on a multipoint video call, participants with sufficient resources will continue to receive HD quality video whereas users with less bandwidth, etc. will receive video scaled to meet their resources.
Unlike some legacy video conferencing solutions, each VuCall user receives the best quality, uninterrupted sound and video possible.
A VuCall video meeting in progress
This diagram shows how different computer setups with different internet connections in a video meeting together send and recieve personalised data streams optimised for their setup.
Roll over each system to see the explanation.
Packet switching
VuCall utilises patented router architecture from technology supplier Vidyo Inc. to ensure full implementation of the inherent benefits of H.264 Scalable Video Coding (SVC).
Unlike with legacy systems, no centralised re-encoding is necessary resulting in much lower end-to-end delay. Each user receives a data stream matched to their available resources, yet the coding efficiency is such that up to HD video quality can be received even on a regular PC or laptop.
Communications quality
Communication quality in a video conference is determined largely by three factors: delay, frame rate and image resolution.
Delay (latency)
To achieve a natural conversation it is very important that the end-to-end delay is kept below 250ms (a quarter of a second). Anything more than this creates unnatural pauses, and can lead to people ‘stepping on each other’ in conversation.
Frame rate
In order to preserve motion quality, maintain lip sync and provide the benefits of low delay, a frame rate generally above 20fps (frames per second) is required.
Resolution
With the emergence of digital cameras, particularly those in mobile phones, many people are familiar with the concept of image resolution – the more pixels that make up an image, the better it looks. Increasing resolution delivers sharper images, enables larger display sizes and creates an overall more pleasing visual experience. But it also puts a higher demand on processing power and network bandwidth which, in turn, imposes a requirement for resilience and efficient encoding and decoding.
VuCall quality
VuCall’s advanced hosted technology delivers high performance in each of these areas – low delay, high frame rates and high resolution – to ensure a far more natural meeting experience.
