Satellite images transmitted from war zones are set to improve dramatically next year with the introduction of internet-based technology.
The pixelated, partially frozen and shaky images transmitted by reporters during the Iraq war will be replaced by smooth pictures, when satellite videophone bandwidth increases from 64 kilobits/sec to 300kb within the next 12 months.
Today’s £20,000 videophone systems transmit signals to a satellite dish. the data is sent down the telephone wires via the Integrated Services Digital Network, ISDN, the digital telecoms technology that can simultaneously transmit voice and data.
But a quiet revolution within the telecoms industry is leading to the ISDN standard being dumped in favour of internet-based systems, said John Martin, technical director for UK firm Motion Media, which supplies compression technology to the makers of satellite videophones used by the BBC and other news gatherers.
The internet protocol (IP) method involves sending ‘packets’ of data, or short signals, unlike satellite ISDN systems which send information in a long stream. ‘There is very little ISDN development. All the major telecoms players are moving to IP which has advantages because it uses data packet-based communications,’ said Martin.
The major advantage of IP is that data is sent only when needed, so if the background of a picture does not change no new data is sent. This enables more efficient use of the available data bandwidth, allowing more information to be sent at any one time.
A new compression standard, H.264, is also set to be ratified this year by the International Telecommunications Union. The technology, which operates in a similar way to the MPEG video software used in many home computers, can handle blocks of data in different sizes.
The new standard will allow twice the current amount of information to be sent, doubling the picture quality provided while using no more bits per second.