Complaints over BBC HD quality

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The BBC has been hit by a storm of complaints over the quality of its BBC HD high-definition TV channel.

In August the corporation changed the encoder technology used to compress the television channel for transmission via Freesat and Sky satellite services.

The change reduced the bit rate - a measure of how much information is transmitted per second - of the transmission from 16 Megabits per second (Mbits/sec) to just under 10Mbits/sec.

At the time a number of viewers complained of quality problems, and the BBC issued a statement noting that a "reproducible problem was identified on certain types of material... The particular problem does not go away with higher bit rates, so whilst an investigation and fix are awaited some changes have already been made to the encoders to try and mitigate the effects."

This did little to appease its critics, however, and since August complaints have continued to appear on the BBC's Internet Blog.

In the latest posting, the BBC's Danielle Nagler wrote that "the majority of viewers watching in normal situations in their living rooms are happy with the picture quality on the channel".

She added that the "concerns we have about picture handling in very specific circumstances... are being addressed and will be fixed through software releases over the coming weeks".

The corporation's critics, however, remain unimpressed. In response to the latest BBC statement, one poster claimed that "even my wife can see a reduction in picture quality and she's got cateracts".

Some speculate that the reason for the reduced bit rate is a plan to use the same video stream for the high-definition terrestrial Freeview HD service when that launches in 2010.

BBC HD customers viewing via Virgin Media's cable TV service are not affected by the picture quality change as Virgin's service uses the older MPEG2 standard running at a bit rate of between 15 and 20Mbits/sec.