BBC to Justify HD bitrate reductions

dante01

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The Beeb has started to reduce the bitrate of its HD broadcasts by up to 40%, even though their original pledge was to at least equal if not exceed industry standards for HD broadcasts. On the BBC Points Of View programme today, a complainant questioned the Beebs reasoning. No response has as yet been given, but a representative of the HD channel is scheduled to appear and will respond to the complaints the BBC have so far received on the Points Of View programme in 2 weels time.

Will the Beeb revert back to the once excellent HD standards they started with or just give a lot of waffle and ignore the people who pay for the service?
 
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Will the Beeb revert back to the once excellent HD standards they started with or just give a lot of waffle and ignore the people who pay for the service?

Definitely the latter imo and it's a shame :thumbsdow
 
I've just sent in a complaint about colour banding on Wild China.
More petrol on the fire.
 
Apologises for jumping into a VM discussion but don't they get a dedicated feed from the BBC rather than take the Dsat H.264 broadcast and re-encode as requried?
 
Apologises for jumping into a VM discussion but don't they get a dedicated feed from the BBC rather than take the Dsat H.264 broadcast and re-encode as requried?

Because the BBC supply the feed and the feed is the same feed they give everyone. Virgin are a carrier and not a broadcaster.
 
Because the BBC supply the feed and the feed is the same feed they give everyone.



So VM do re-encode the same broadcast SKY and Freesat boxes use, pity:(
Thanks for that, I always thought VM had a dedicated feed as they do with many of the SD channels rather than lift them from DTT and Dsat broadcasts.
 
When similar issues were raised on Feedback on Radio 4 about the falling quality of DAB Radio the official answer was that 'we've done a survey and most people are happy with it'. Can we expect the same answer with regard to HD TV ? The fact is that many people cannot tell the difference between HD and SD and their TVs and receivers are probably not set up properly anyway. What really matters is that they can get 500 channels !!!
 
When similar issues were raised on Feedback on Radio 4 about the falling quality of DAB Radio the official answer was that 'we've done a survey and most people are happy with it'. Can we expect the same answer with regard to HD TV ? The fact is that many people cannot tell the difference between HD and SD and their TVs and receivers are probably not set up properly anyway. What really matters is that they can get 500 channels !!!


What they did with DAB is change to AAC encoding. Instead of maintaining the same bitrate they used with MP3, they chose to reduce the bitrate because AAC compression is less lossy than MP3. They stated that the quality was the same while still reducing bandwidth requirements. What they should have done is use AAC, but not reduce the bitrate in order to provide a better service without increasing bandwidth, but they chose to use improvements in encoding technology to reduce bandwidth rather than improve quality.

I'm guessing that they'll throw the same reasoning at the consumer when it comes to digital TV?
 
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I thought this might be of interest:

BBC admits to problems with new HD encoders

The BBC has admitted there are technical problems with its new high-definition encoders, which has led to criticism that picture quality on the BBC HD channel is not as good as it used to be.

Complaints arose after the BBC deployed the new encoders, which use a lower bitrate than the previous ones. Bitrates were apparently cut from 16mbps to around 9-10mbps.

The Beeb has told whathifi.com that there is a "reproducible problem on certain types of material" which does not go away if higher bitrates are used. So the Corporation has referred the matter the the coder manufacture to investigate further, and is waiting for a fix.

Here is the BBC's statement in full:

"The BBC has deployed a new set of HD encoders. The current bitrates were picked after much side-by-side comparison of the old and new encoders using a wide range of programme material. While it is impossible to achieve parity in all formats the new encoders were judged to be giving equal or better quality in most cases."

"However, there is no test like putting these to air, and when we did, a reproducible problem was identified on certain types of material. We have shared this information with the coder manufacturer so they can investigate further. "

"The particular problem does not go away with higher bitrates, so whilst an investigation and fix are awaited some changes have already been made to the encoders to try and mitigate the effects. In addition, the new encoders also fixed other problems, unrelated to picture quality, which the BBC received complaints about."

The world's No.1 home cinema, hi-fi and TV buying guide


Picture Quality on BBC HD: full response to complaints

Hello Everyone

I thought that you might like to see the detailed response which I have sent to someone who contacted me regarding the picture quality issues which are under discussion here:

"...Your complaint refers to the introduction of the new transmission encoders for BBC HD which were introduced into operations on Wednesday 5th August. There was an extensive process of assessment in advance of the selection of new encoders for the BBC HD service, using both objective and subjective criteria. The encoders which were chosen then went through further testing in advance of operational use, not only for picture quality but for compatibility with the Sky and Freesat platforms and their ability to deliver other services such as subtitling and surround sound successfully.

The new encoders were intended to help us in handling the wide range of material which the BBC broadcasts in HD, and to help to improve the picture quality of some of our most challenging programmes. These may combine progressive and interlaced shooting or where the BBC has limited control over some aspects of the broadcast chain. I believe that the new encoders have achieved this in relation to programmes such as the series of BBC Proms broadcast, Gardeners' World, Rick Stein's Mediterranean Escapes and the recent Athletics World Championships, for which our coverage using the host broadcaster feed was as good as and sometimes better than other broadcasters covering the same event. However we of course continue to assess coder settings against the wide range of material which they have to handle to determine the best settings on an ongoing basis.

Following the introduction of the new encoders, there were some issues around the handling of some pictures - primarily mixes and fades - which we acknowledged through the BBC HD blog on picture quality almost immediately. We have worked with our encoder supplier to address these issues in the long-term, and also put in place interim changes to minimise the difficulties. That the encoder change should generate problems for viewers watching BBC HD content is of course a matter for regret, but I do not believe that this was the result of errors in the preparation process.

You have also highlighted the issue of the bit-rate at which BBC HD broadcasts, and the changes to this over time. I do not believe that the problems that arose following the introduction of the new encoders had anything to do with the broadcast bit-rate, even though they coincided, as you have rightly identified, with a reduction in bit-rate for the channel.

One of the central issues in selecting new encoders for BBC HD was to deliver pictures at the same or improved quality while allowing a reduction in the channel bit-rate. As MPEG 4 encoders have evolved, the relationship between bit-rate and picture quality has also shifted. This is not an issue that is specific to BBC HD, or to the encoders that we have selected.

The BBC has an absolute responsibility to use bandwidth efficiently - whether on digital terrestrial muxes or on satellite. Bandwidth is not unlimited, and on UK-footprint transponders the demand for capacity is very high. The current bit-rates were selected through a process which directly evaluated quality on the new and old encoders, using a wide range of programme material and both subjective and objective assessments.

Bit-rate is not the only factor affecting picture quality and a higher bit-rate will not automatically deliver higher picture quality.

HD is still an evolving production technology. A variety of production techniques are - in my view quite rightly - deployed as experimentation continues to explore what HD can delivery creatively.

As in standard definition, it is also important that HD delivers a range of "looks" for producers, appropriate to the nature of the subject matter. I do not prescribe a single standard for HD work for the BBC. Decisions regarding frame rate and progressive versus interlaced styles are the responsibility of individual producers. These choices do not impact on quality provided that the camera is set up properly and the shutter speed set correctly, issues on which the BBC HD team provides ongoing advice and guidance. As the discussion on the BBC HD blog suggests, there is a range of views around these issues, and the degradation or quality they may bring to HD pictures. It is worth noting that 25 frames progressive mode in fact has more resolution than a 25 frame interlace image, and is used by the majority of drama, documentary and natural history programmes to great effect.

While very clear, sharp images have become closely associated with HD, it is important not to confuse "sharpness" with resolution. The use of electronic sharpening on standard definition pictures can make images clearer but does not increase the amount of information in the picture, one of the defining features of HD.

Electronic sharpening is not a characteristic which BBC HD encourages since we prefer images to look more natural, and to allow directors to offer contrasting focus in order to highlight the key features in a scene. Indeed, some of our dramas are now using the latest large image format cameras. These cameras use an image sensor about the same physical size as a 35mm film frame that gives the image a very shallow depth of field. This will put all but the key subject out of focus and allows a director to use focus as a story telling tool.

HD picture quality is not purely about a crispness of image, but about a richness of image which comes from the amount of detailed information included.

Within the BBC HD team we work consistently to explore new HD technology with a particular view to enhancing picture quality across the range of programme projects with which we are involved. Filming in certain environments or using small cameras remains challenging, and where it is not possible to deliver HD pictures to the standards we set, we limit the use of lower quality images to a maximum of 25% of an individual title.

Finally, you raise the issue of surround sound and the number of programmes broadcast which offer a 5.1 sound mix. Wherever possible we buy series and films with surround sound tracks, and try to ensure that sound is captured in this format for outside events. But 5.1 sound is not always available, and a genuine surround sound mix can add substantially to production costs in HD at a time when we are concentrating the resources available to increase the total volume of programmes made in HD. At present we do not routinely "up-mix" programmes from stereo to surround.

I can assure you that picture quality is a very important part of the work that we are doing in BBC HD. We clearly have different views on the picture quality that is delivered and the factors that contribute to it, but I do believe that we share a perspective that the quality of images is central to delivery of HD television.

I want to add that the BBC HD blog is a very important discussion and communications forum for us, but as you have clearly observed we don't respond to every single comment raised on it. We do take on board all the views expressed, and look seriously at substantive issues that are highlighted, whether they attract one comment or many.

I am sorry that in this case you feel that your original contribution did not receive the attention which you believed that it should have done."

Danielle Nagler is Head of BBC HD, BBC Vision

http://www.bbc.co.uk/blogs/bbcinternet/2009/09/picture_quality_on_hd_a_respon.html


Danielle Nagler will be appearing on Points of View, scheduled for Sunday 8 November.
 
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Does the bitrate make a difference?


The following is more to do with what has been labelled as HD downloads, but the same is true of any form of compression or reduction of bitrate for the purpose of reducing bandwidth:

Giz Explains: Why HD Video Downloads Aren't Very High Def - Hd movie downloads - Gizmodo

Extracts:

It's all about bitrate: How much data is packed into a file, described as bits per second. Generally speaking, a higher bitrate translates into higher quality audio and video, though quality can also be affected by codec—the encoding and compression technique that was used to make and read the file—so bitrate is not an absolute mark of quality, but it's still a very good indicator.

The bits make a huge difference when you get into fast moving stuff like sports or action movies—to be frank, they'll look like splattered, smeared **** in highly compressed low-bitrate vids.

No matter how awesome MPEG-4 compression—or whatever the codec of the month is—gets, it can't work miracles when it's missing bits.



Danielle Nagler said:
The BBC has an absolute responsibility to use bandwidth efficiently - whether on digital terrestrial muxes or on satellite. Bandwidth is not unlimited, and on UK-footprint transponders the demand for capacity is very high. The current bit-rates were selected through a process which directly evaluated quality on the new and old encoders, using a wide range of programme material and both subjective and objective assessments.

Bit-rate is not the only factor affecting picture quality and a higher bit-rate will not automatically deliver higher picture quality.

What is really strange about the BBC dropping the bitrate is that they already lease the bandwidth and therefore save nothing by reducing it. It sort of gives credence to claims that they've done it to make BBC HD Freeview look as good as you'd get via satellite and cable, instead of simply supplying a lower bitrate just to Freeview because of its limited space for expansion, they've decided to make everyone's life miserable :D

What has the BBC actually gained from the bitrate reduction?
 
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Hi

I am the complainant from Points of View and would be grateful for all of you to send your comments to them asap!
 
What has the BBC actually gained from the bitrate reduction?
The BBC pays for an overall bit bucket. Anything they can shave off BBC HD without harming the picture pays for improving the SD channels and shoving more things in like the F1 alternate angle stuff on the red button.

Different encoders need different bitrates to give equivalent performance; that much has been demonstrated time and again by the progression in image quality over the life of DVD. So if they say the image problems are a specific bug in the new encoder, not bitrate starvation, I'm not immediately inclined to disagree. Let's see if it gets fixed, first.
 
I thought this might be of interest:

BBC admits to problems with new HD encoders



The world's No.1 home cinema, hi-fi and TV buying guide


Picture Quality on BBC HD: full response to complaints



BBC - BBC Internet Blog: Picture Quality on BBC HD: a response


Danielle Nagler will be appearing on Points of View, scheduled for Sunday 8 November.

Watched Points of View today and I'm non the wiser. The encoding issue with the new encoder wasn't even mentioned and Danielle Nagler seemed to be inferring that nothing would change in the future. She also seemed very dismissive of the complaints, as if they were unfounded, yet did admit that some contents had less definition and then went on to justify it by saying HD isn't all about High Definition. Eh????

Doesn't the fact that viewers have noticed a difference in picture quality in itself suggest there is a less favourable picture or do the BBC just broadcast the HD channel to keep anielle Nagler in employment?

She also proclaimed that there's no evidence that lower bitrates result in poorer picture quality. I think she'll find that there's plenty of evidence to suggest otherwise. Does she actually know what she is doing or anything about HD?
 
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HD isn't all about High Definition
Well I didn't watch it so don't know what context it was said in, but that seems a pathetic statement to make.

Does she actually know what she is doing or anything about HD?

I think she knows exactly what she is doing. It's called PR ********.

All I know is there's barely any difference between BBC 1 and HD now.
 
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All I know is there's barely any difference between BBC 1 and HD now.

Yeah, even Jeremy Vine said this and this is what basically prompted the statement about HD not being all about high definition. No real explanation at all, just gesticulating about better depth of colour. But why is the depth of colour no better then????

I don't know about saving bandwidth, but surely they are wasting it if no one can actually tell the difference between the two. Why not just show it on the SD channels and save even more bandwidth? :D
 
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But why is the depth of colour no better then????

To be fair, I'd say it is.
But not by much.

And while I'm ranting, I've noticed that the last few progs I've watched have been in stereo. What's happened to the 5.1?
I suppose that's an "improvement" too?

BBC HD is rapidly becoming pointless, imo.
 
I think the big issue is consistency. There isn't any and they (Danielle Nagler) doesn't have a clear or concise answer. Why admit it when you can claim that the viewers themselves are wrong? Sorry, but the viewers themselves take priority, not a handful of BBC employees sat around a table thinking up excuses or ways of dismissing the issue altogether.

Danielle Nagler seems to imply that the viewers are less attuned to what they should be seeing than herself and what she defines as HD is what HD is?

If what Danielle Nagler defines as HD is HD, why are people noticing the difference now and what were the BBC broadcasting prior to this???
 
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Just as I suspected, PR bull.

And she mentioned the possibility of a second HD channel!!!

Expect the bitrate of the current one to be massacred even more then :thumbsdow
 
Oh and HD isn't about "clearer and sharper", it's about detail.
Well excuse me, but don't detail and bitrate go hand in hand :confused:
 

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