Network and Bandwidth Requirements

Network Requirements

When multimedia data are transferred, certain requirements have to be met concerning the bandwidth (transmission rates) in the network, which play an essential role for the acceptance of the application.

In video and web conferences the data rate usually is between 128 kbps and 768 kbps. The video compression (H.264, VP8, VP9) used for the transmission is very effective and used for static parts as well as moving parts of the video.

At a transmission rate of 128 kbps, the frame rate and sharpness of the moving parts are of low quality. With rising data rate the influence of movements decreases considerably, at 768kbps even widespread movements are displayed quite sharply. At 4 Mbps, all parts of the image are very good.

The transferred resolution is almost always 720p or 1080p. Thereby, good sharpness and anti-aliasing are achieved.

In the case of LAN (and Internet), a problem occurs due to the fact that the available bandwidth is used by other applications at the same time. If the video conference lacks bandwidth, even only for a short time, and packages are lost, display errors in video or audio or both appear.

Bandwidth allocation (Quality of Service - QoS) for certain applications is usually not available. Therefore, the provider usually does not guarantee the required connection qualities. This situation can be exacerbated when communicating between different providers.

Bandwidth Requirements

Data streams in networked multimedia applications require the following bandwidths in order to work:

The exact bandwidth requirements of the video image depend on the picture size (the desired resolution of the sending side), the colour depth and the transmission rate (images per second).