With my home country (England) out of the World Cup, it seems an appropriate time to focus on some of the TV coverage of the tournament, and in particular a few pet peeves.
I was one of the lucky few in the UK to get High Definition installed in time for the World Cup, after the main provider (Sky TV – owners of Fox) messed up their launch completely by underestimating demand. Stories of people rushing out to buy High Definition TV sets a week or two before the World Cup, and then finding out from Sky it would be August or September before they’d actually get service, were commonplace. Lots of people very upset.
Despite these problems, the service itself when working is outstanding, and indeed my home became something of a drop-in, with friends and colleagues turning up to watch games in ever increasing numbers. The only real consolation of England going out, is that I now have a large collection of assorted beers.
Coverage of the World Cup in HD by the BBC was phenomenal, and my respect goes out to all the feed managers managing the lines, and the make up artists, who must have been under extreme pressure by aging presenters to cover up their lines. (HD is not welcomed by presenters).
My peeve, however, is to do with the compression and bandwidth allocation that Sky (and other digital TV distributors) use to cram lots of channels onto their systems. Not too long ago, prior to the advent of digital TV, there used to be very strict regulations as to the picture quality of a TV channel. Broadcasters and engineers would get their wrists slapped very heavily for failing in this area, and I remember many times sitting in an edit suite with a technician, working on white levels, black levels, and other intracacies, simply trying to get the signal passable for broadcast.
All this is now rapidly becoming ancient history. Part of the reason is the growth in reality television, and broadcasters campaigning to be allowed to make greater use of consumer camcorders. These are lower quality obviously than the cameras traditionally used by broadcasters, and we’ve all grown accustomed to this style of shooting. There was a time when viewers simply wouldn’t have accepted an entire program shot on DV.
But the problem is that signal distributors (such as Sky), seem to be using this as a smokescreen to funnel ever decreasing picture quality to our TV sets, regardless of how its shot. And they appear to be doing it in some naughty ways.
Sky for instance is using a system that allows them to apply different quality settings to individual TV channels. In technical terms they are reducing or increasing the bandwidth and compression allocation for each channel. Since Sky is also a broadcaster with their own channels (Sky One, Sky Sports, Sky Movies, etc), you can guess which channels appear to be getting the best picture quality – their own. In fact there is circumstantial evidence that they are dynamically allocating bandwidth for individual TV programs, and in my opinion, lowering it when the program is a competing program, such as a high profile sports event.
How bad is the problem I’m talking about?
Let’s just say that watching a football match in standard definition on a competing channel like ITV, and on a big screen TV, is almost unwatchable. It is like watching a really bad JPEG image 25 times a second. The grass and crowd have huge compression blocks on them, and the players have very visible JPEG halo’s. It’s abysmal, and it’s a disgrace.
Now while I fully understand that to enjoy the benefits of a multi-channel universe, it’s necessary to compress the signals to fit them all down the pipe, I do not accept the level to which the signals have degraded. It seems to be getting worse and worse, and with the rollout of more bandwidth hungry HD channels, I can only imagine it will continue in an increasingly downward spiral.
So the irony of digital TV is that we now have far worse picture quality than we did 10 years ago when it was analogue. Distributors like Sky have no incentive to make standard definition pictures better, they want people to go to HD, and they have poker, adult and dating operators clammouring at their door to open up new channels. More channels means lower quality overall.
Sky I’m sure know that the people who are aware of this problem are the same people who will gravitate quickest to HD, so they’ll keep quiet or go away. But how long will it be before the HD channels also start going the same way?
For now at least, the High Definition channels do not appear to be suffering from the same problem, although there is clearly visible compression if you look closely. The problem is that it is now much more difficult to define acceptable picture quality in an era of digital compression. How do you quantify it, how do regulate it, how do you legislate it?
I’d be interested in hearing from others on this topic. Please take the trouble to register for the comments system, or drop me a line at the address on the contact page.
I’ve a feeling this is a subject I’ll be returning to in future!
(Here’s an alternate view on the subject of regulating digital tv standards.)
Good to hear it’s not only me having this problem. You can really see the difference between ITV and Sky Sports 1.
Interesting theory, but little factual evidence.
The proof is in the pudding. To find it, you need a hacked SkyHD+ box, that you can use to record, or time-shift broadcasts, and plug it’s Hard Drive into your PC (several ways of doing this) and read the stream directly, as it was sent… then you can perform bandwidth analysis on individual programming.
The nightmare story I have heard from people who have tried this, is that Skys HD channels are broadcast at nearly half their correct horizontal resolution… Even SkyOne and SkyMoviesHD.
This is similar to the “Anamorphic” widescreen of standard definition, and works on the assumption that the human eye usually notices the quality in “scan lines” of a broadcast quicker than they spot a drop in horizontal quality. (I think that is only true of raster scanning displays… and would like to know the details of those psychological experiments, there is something about it on /my/ blog, if you’re interested.)
Apparently, they do broadcast BBC HD in it’s full, and correct HD horizontal resolution. So if they limit them to the same bandwidth as their own (reduced resolution) HD service, you will get more compression artefacts due to the higher “actual” resolution.
Now, Sky usually provide via microwave transmissions from the Astra satellite, but reports are that VirginMedia do not follow this practice on their HD Digital Cable TV service. There is pretty much 0 chance of interference down either the Virgins’ fibre-optic backbone or the shielded copper line they run to your home however. So they can probably squeeze more bandwidth out of their cable than Sky can pull out of the air.
Sky should still have more than the DVB Terrestrial VHF broadcasters, due to go HD this year.
Further more… you quote “live sports events” as being among the poorest quality. I’m an F1 man my self, and know that rapid panning is a bandwidth eater, and usually causes really bad macro-blocking (the lousy jpeg you where speaking of) unless the motion compensation processor is given a large amount of time (3 – 15 seconds per second of actual footage on a top end PC) to perform an extensive search of the previous /and/ next 3 to 5 frames.
You can’t use parallel processing (much) to speed this up, and even todays super-computers could barely manage it in “real-time” even if it was the /only/ job they had to do. That’s just not feasible if you are going to call a sports event (the worst source material for this issue anyway) “live coverage”.
Do you find similar issues with pre-recorded material which competes for “prime time viewing” slots?
Bob, thanks for your comment. I wrote this article a long time ago (2006). I don’t sense that Sky is so blatant these days with this, but it is clear to me that some channels have greater bandwidth/resolution than others and I wonder how much control the broadcaster has over that. It’s an interesting point you make about the source video being at half the resolution – I’d never heard or considered that.