BBC boosts HD bandwidth and quality

The BBC has launched a raft of picture quality improvements for BBC HD just weeks after campaigners took their complaints direct to the channel’s bosses. The changes include Variable Bit Rate encoding, a fix for mix/fade problems and a new approach to noise in pictures.
The improvements came several weeks after the BBC HD Campaign group visited BBC TV Centre in London to meet Danielle Nagler, head of BBC HD, and principal technologist Andy Quested.

John Temperley, of the BBC HD Campaign, said: ‘We are pleased to see that after nearly a year of campaigning, BBC HD has taken these measures and, as we expected all along, the results have been a significant improvement in picture quality.
‘We feel these improvements vindicate our campaign, which will now continue with attempts to move the BBC to a Full HD service with a resolution of 1920×1080.
‘We look forward to the BBC meeting the requirements of the license for BBC HD by offering a very high quality technical service to viewers, by adhering to, or seeking to exceed, industry standards for picture resolution.’
The BBC said: ‘The BBC is pleased that viewers feel that this set of changes has enhanced their experience of HD.’

The BBC HD Campaign began in August 2009, when the BBC introduced new high definition picture quality encoders and reduced the bandwidth of BBC HD to a constant 9.7Mbit/s from 16Mbit/s.
This is lower than used by Sky’s HD channels and lower than the BBC HD channel provided by BBC Worldwide to other broadcasters in Europe.
Viewers began to complain about a decrease in picture quality, but the BBC said the problems being seen were due to programme makers experimenting with HD production styles which were not always successful.
Variable Bit Rate encoding allows the broadcaster to maintain the same average bandwidth, while increasing the bit rate for more demanding scenes such as fast movement.
The ‘mix/fade’ fix treats a specific problem in changing scenes, while a configuration change for ‘noisy’ video means the BBC no longer needs to add noise reduction, which often reduced the overall picture quality.