BBC confirms use of variable bit-rate encoding on HD channel
The BBC has confirmed that, following criticism of worsening picture quality on its HD channel, it has switched to variable bit-rate encoding.
Last year the Beeb introduced new high-definition encoders which cut the broadcast bit-rate by 40 per cent, down from 16Mbit/sec to 9.7Mbit/sec. This brought howls of protest from some viewers, who complained to the BBC Trust and formed the BBC HD Quality Campaign Group.
Initially the BBC admitted there were teething problems with the new encoders. Subsequently, after further tests were carried out, it claimed that HD picture quality had not been compromised, saying that no technical fault could be found.
But now, following a meeting in April between the HD Quality Campaign Group, the Head of BBC HD, Danielle Nagler, and Head of Technology, Andy Quested, the Beeb has switched to variable bit-rate (VBR) encoding. (You can read more about the visit in this BBC blog).
What does this mean? Well basically, it's a process which maintains a similar average bit-rate despite being able to allocate more bandwidth for more demanding scenes – such as fast-action sports like football – when required.
"The BBC is pleased that viewers feel that this set of changes has enhanced their experience of HD," says a Corporation spokeswoman.
Critics of the previous encoding system say the new VBR system has resulted in a noticeable improvement in picture quality, particularly during recent FIFA World Cup 2010 broadcasts.
Have you noticed a difference? Let us know what you think in the Comments box below.
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Comments
Back when the BBC started squeezing the bandwidth on DAB radio, I'd just bought a very nice Sony ES DAB tuner. I wrote to the BBC to complain at the reduction in quality and they replied with a stock letter extolling the virtues of hiss free reception and crystal clear sound. It looked very much they'd not even read my Email.
Now a few years later and another £600 on an HDTV and we see it happening all over again. When I bought my HDTV just over 2 years ago, BBC HD pictures were excellent and I spent evenings marvelling at the colour definition and detail in the pictures. Wind forward 2 years and it's not very much better than SD. Try watching something on BBC1 that's been filmed with HD cameras and downscaled to the SD channel and compare that with the native HD during a simulcast. You'll be hard pushed to tell the difference.
"ghoughto June 23, 2010 18:39
Does it make a difference through which medium you receive your HD pictures - Sky+HD/FreeviewHD/FreesatHD - I have the first 2 and I'm sure Sky downscaled ITVHD for the first England match."
ITV HD switched to SD after the commercial cockup a few mintues into the game . . . so yes it was a worse picture.
Does it make a difference through which medium you receive your HD pictures - Sky+HD/FreeviewHD/FreesatHD - I have the first 2 and I'm sure Sky downscaled ITVHD for the first England match.
Some of you must not have very good tv's or maybe your settings are wrong ?
Itv HD is quite a bit sharper looking than BBC's HD channel.
I'm using Virgin's Samsung HD box.
Watching on Virgin Media HD here. Have to say the quality of the world cup matches has been miles better on BBC HD than ITV HD.
With ITV, I've had to sometimes check that I was definitely watching the HD channel, the quality is that sub-par.
is this whats forcing my Fortec HD box to keep rebooting? Only happens on BBC HD.
I paid out a small fortune for all my HD gear. And I had to run the risk of getting on the wrong side of her indoors.
Just think of the full HD pictures I cried.
Ok she said, if you think it will be better for us.
�3,500 later. OH DEAR!
Wife says we could have gone holiday with that money or changed the car even.
Thanks BBC HD and ITV HD
Does anyone have problems with Virgin Media HD TV?
Of all HD channels BBC is the best but overall quality is poor.
ITV HD is no better than standard.
I have a Panasonic TH-42PZ80 and use QED and IXOS HDMI interconnects.
I've been particularly disappointed with BBC HD tramssions for the World Cup. I'm viewing on a large, top quality Panasonic LCD panel using FreeSat.
Close up shots look noticeably more detailed and sharp than SD pictures, but Stadium wide shots look no better. I thought this was down to the source cameras or possibly the satellite link, but obvious it is down to the BBC.
Why are they using VBR and not providing full HD picture detail at a full 720p.
Perhaps if the BBC sack a couple of senior managers it will pay for the bandwidth required!
I find the advantage of the BBC HD coverage is that it shows the goals
Have to say I've commented a number of times (with friends) since upgrading to sky HD how much better the HD picture on BBC is compared to ITV's... and well before I heard anything about changes in transmission bitrates. I just think ITVHD looks soft compared to BBCHD, just hope it stays that way (or ITV improve their quality).
Something tells me that the BBC is attempting to pull an "Emperors New Clothes" trick here. Announcing that something has changed, when in fact nothing has really changed. BBC HD still looks soft compared to before they started to meddle with it. Of course there will be people who claim that they can see a difference, but simply put, they're eyes are playing tricks.
The football on ITV looks sharper.
With a Bush HD Freeview box,upscaled to 1080i,with latest updates installed the picture knocks spots off ITV HD.
Watching Wimbledon this afternoon supurb picture,no bluring, even her indoors commented how sharp it was.
Sound quality through the Yamaha 765 (Dolby Digital) is spot on.
worse to my eyes, I prefer ITV HD to the BBC.
better? its got worse this last week, blocking, sound sync problems!!
cannot watch hd at all and all in time for the world cup too!
well done bbc you monkeys!
o dear o dear
Football looks very good now although still some motion blur issues.
However, other BBC HD programmes look no better, maybe worse in some cases and Linosat have reported bit rates as low as 3.5mbs according to some posters on the BBC blog. A worrying development if correct as it looks like give with one hand and take with the other.
but the resolution is still 1440x1080 rather than the full 1920x1080.
So good progress but still lacking.
Still looks flat to me. Doesn't have the almost 3D effect that BBC HD broadcasts had a couple of years ago, that were stunning.
cant say ive noticed a difference yet...heres hoping..