I agree artifacts can be annoying, but TBH I don't notice them unless it's really bad i.e. massive blocking on moving water or lots of dancers moving quickly under moving lights etc., on the ITV1 HD Granada samples below the difference between that and BBC One HD isn't that great as the scenes weren't that demanding- if some scene had required 14Mbps on 1440 obviously it would have been noticeable as 1920 is fixed at 10Mbps currently.


Average of 16Mbps- I don't think we'll ever see that, maybe maximum 18Mbps if they get more space on the new Astra satellites. I just hope they don't insist on sticking to 1440 just because Freeview can't handle 1920, C4 HD and ITV1 HD/STV HD clearly don't care about this rule....

Update to my old post below with ITV1 HD Granada and BBC One HD lossless png screenshots - you need to click the the 'download this image' button to see the actual png. Generally the ITV1 HD Granada pngs have less artifacts than the lossy STV HD jpegs, more detail in some cases due to this, BBC One HD has generally less artifacts but less detail. For some reason ITV1 HD/STV HD was slightly cropped on the left and bottom, with thin black bars below and right.

@jzee: Nice work. I think these again give the lie, if any more proof were needed, to the claim that 1920*1080 shows no more detail than 1440*1080. (OK, there is room for potential criticism that some could be comparing I frames to other frame types and so are not valid, but this is happening in every example and always in the same direction, so that seems very unlikely.)

The BBC spent a long time explaining why this was the case, quoting Nyquist limits, the Kell factor and so on. Some of this was set out by impressively qualified people, but it did end up being rather less clear cut than it seemed to be at the start. And here we are with sound evidence against it.

The BBC should drop this argument. I think it came about because the 1440 issue appeared at the height of the bitrate wars , and at that point they were so keen to say bitrate was not always the deciding factor re picture quality that they tended to imply it was not a factor at all. *If* they want to say they'd rather stick with 1440 in order to avoid/reduce bit starvation artefacts, that would be fine. But maintaining it has no impact on picture resolution seems implausible--especially now.

Indeed, I think the reality is it is about the bandwidth constraints on Freeview, you couldn't fit 4-5 1920 channels on Freeview HD without relatively noticeable artifacting. It's easy to say it only affects fine detail, but basically, anything that isn't a smooth surface and is in focus will lose detail in 1440 vs 1920, and, it has a really noticeable effect on reflective objects, reducing their brilliance and even colour in the case of the red and green jewels in the Duchess of Cambridge's tiara in the first example.

By chance I came across this, 'The BBC’s Efficient and Effective use of Spectrum' by Deloitte and Touche. I think it's the document you mentioned. So we find

4.51 On Multiplex 1, the majority of those capacity gains would be made as a result of reductions in picture resolution to BBC THREE/CBBC and BBC News 24. On Multiplex B, slightly less than 1 Mbps of capacity could be gained by reducing BBC FOUR/CBeebies’ picture resolution, while approximately 0.5 Mbps could be gained by increasing GOP length.

The basic cast of the report on issues of technical quality is that the BBC have made decisions that cost bitrate and aren't based on what it calls 'robust consumer research' on tradeoffs of quality v choice.

1.16 The BBC does not appear to have a sufficiently value-based process for making decisions relating to the trade-offs between capacity and picture quality. We recommend that, going forward, the BBC should undertake robust subjective audience research to support decisions regarding the picture resolution of TV channels. Lower picture resolution might result in poorer pictures, but the BBC should test where the consumer acceptability threshold lies.

The entire framework of the thing is based on the assumption that picture and audio quality should be set so that the majority of the audience find it acceptable. This could of course mean 51%. All existing research reservations and about technical quality are brushed aside apparently because they are not measured by this yardstick. The consequences of this framework are inevitable. We learn for instance that

6.8 There has been some concern from some listeners about audio quality being lower on DAB than FM. However, research by Ofcom suggests that most listeners think DAB sound quality is at least as good as FM30.

and

4.33 Ofcom have told us that they have received very few complaints about the picture quality of other public services broadcast channels, which operate at lower bit rates, suggesting that consumers might find lower levels of picture resolution acceptable.

As everyone knows, the DTT PQ of ITV one is regularly utterly diabolical. Even I, being well used to their antics, couldn't believe the state of the FA Cup final the other day. Yet, very few complaints, so all is well.

In the name of increased 'choice' and thus 'value' (a hardwired unexamined assumption if ever there was one) the accountants will drive down technical standards as hard as they can.

That should of course be

Thanks mwardy - that was the one.

The depressing thing is that no one at the BBC dared to rip this nonsense to shreds.

If we were to apply the same argument to content, then programmes on BBC Four and Radio 3 should be scrapped immediately, since the vast majority of people are happy with the X factor and Heart.

Cheers,
David.

I thought I saw somewhere in the dim and distant past that the BBC strove for excellence. Maybe that's just my imagination though.

This has been exposed as deliberately misleading/invalid as people equate reception i.e. hiss or lack of hiss as sound quality issue, most people don't know about compression or the negative effects on sound it can have unless they have had it explained to them.

Good point. I'm not surprised by it at all (do you have a link BTW?), but of course for the accountants it doesn't matter a hoot. It's what the consumer wants that counts.

The last thing these types want is an educated audience who would know what they are missing. The more pliant and accepting they are of whatever is put in front of them, the better.

Not since the John Birt era when the accountants came in - and whole departments got sold off! They abandoned having a "Director of Engineering" at board level about then AFAIR!

So the BBC has kept the bit rate higher than the accountant/consultants want ... GOOD


But They were looking at "is the BBC using a scare resource as efficiently as they should be ?"
note that the economist would say that as the market price of DTT is £6 per bit per year to 70% population and must be at least be twice that to 98.5% ..... so should the BBC be notionally spending a national resource of market value say a half Billion pounds a year .... (say 2*20 meg bits *£12 = 480 Mega pounds)

It may be a nonsense to most people but it is how Spectrum Pricing works ....!

Agreed! But the report is pushing the BBC pretty hard to stop doing this. It finds all sorts of things wrong with existing research. For instance people making PQ judgments in a test in Hull came up with results that clearly didn't suit the report writers. They complain that the test subjects were not told that reduced PQ can result in an increased number of channels, and seem to automatically assume that if the audience had known this they would have changed their judgments. And they pooh pooh the BBC's own test method of deliberately reducing PQ and seeing if the complaints flood in. (The main problem they seem to find with this method is that the complaints did indeed flood in.)


But in the report efficiency is explicitly being equated with whatever level of picture quality is acceptable to the majority, which could mean 51%. It could be technically lousy but it wouldn't matter. IMO this is a bad model for PSB, especially for licence funded PSB. I'd imagine you agree?

There is still some distance between the BBC's practices and recommendations like this, thank God, but people striving for high technical standards (and this clearly includes you from previous posts) are obviously under pressure to cave in.

Indeed, in those days the accountants told the Beeb that their biggest problem was that they were stuck making radio and television programmes, and the sooner they stopped that the better they'd be!

On the earlier subject, it looks Political Correctness won the day!

Anyway, I have to agree with MWardy. Just because a majority say something is acceptable doesn't mean that its good quality or an acceptable standard to many even if they are in a minority (which as you pointed out might be a number very close to that of the majority - ie. 51 / 49%).

The problem with canvassing Joe Public as whole for views is that there are a large number of variables in play such tv quality, settings (good or bad), eye sight, opinion, interest in tv etc etc.

These can have a profound effect on an assessment of PQ. eg. Suppose someone has a cheap tv that doesn't carry detail well. The fact that they can't see a difference on their tv between 1440 x 1080 and 1920 x 1080 doesn't mean it isn't there. So how can they make a judgement on quality on something they can't see? They may well if canvassed, report they find 1440 acceptable but if that's because they can't see the difference others can with 1920, how does that convey a representative opinion? It may well be the case in 6 months they buy a different brand that does convey the detail and their opinion would be different but this side of a re-canvas that difference in opinion would never be known.

Equally when you judge sharpness and colour etc. Most tv settings from the factory vary wildly so how can you get a real opinion on these from a random selection of the audience when there are highly influential factors in tv settings that come into play?

The only real way you can judge PQ is from a quality calibrated set, because although most viewers don't have calibrated sets, its the only way of producing a picture that is tv neutral that will display properly on a tv if its properly adjusted. Tuning the picture to any other variable inevitably results in a picture that is terrible for someone who's tv is tuned to the opposite settings. With a neutrally tuned broadcast its always in the middle and if someone isn't satisfied with their picture which is acceptable to those with calibrated sets, they can always be told to tune their tv to neutral using one of the many calibration methods available.

On the BBC's political position, efficiency to my mind comes from delivering the best PQ reasonably possible for the least amount of resources. The key here though is the best PQ reasonably possible. This means essentially the best PQ without going over the top ie delivering the best possible picture quality before gains exceed visible worth (ie noticeable improvements), so it may well involve a high amount of bandwidth resources if that's the least necessary to deliver that high quality of picture.

However it doesn't mean the best picture quality available for the least usage of resources which seems to be what the accountants are wanting.

PQ should come 1st but delivered at a level that's the maximum without wasting resources through non visible gains. It shouldn't be about restricting resources and delivering the best possible PQ limited by the resources.

Respect for everyone including those not so fortunate as others won the day over bias and bigotry.

I don't want to diverge this into something the moderators feel the need to jump onto again. However, there was no bias or bigotry just a point that in order for a vote to be representative you have to select your audience in such a way as to be representative of the average audience in order to achieve a neutral result. Selecting neither rich areas exclusively or poor areas exclusively would achieve that.

eg If seeking opinions on fox hunting you wouldn't expect to canvas only the Royal Estates. TV opinion polls are no different.

In the interest of preventing moderation, that's my last comment.