Years ago we had a Sony TV with remote. Press a button on the remote and the channel would instantly change to the one selected. (Well so fast that no delay detectable).
Now, we have Freeview STB, a remote for it and of course for the much newer TV. Press a channel change on this - wait 3 seconds, realize the damn button-press hasn't registered, try again etc. Far far worse that years ago. Nothing wrong electrically with the kit or remote control - just poorer performance.
Also, the remotes seem to be edge triggered rather than level. I'm sure there's a great reason for it - but the old level-trig was better inho.
footnote: Anyway after a 30 channel hop with nothing worth 1p to watch - the off switch still works :-)
footnote II: Am I the only one who prefers the old analogue fuzz when signal dropout/interference occurs - rather that this pixelation, a green Hue Edwards and sudden sound cutoffs?
And there's only 5 to switch between to find out there's nothing on, which takes no time at all. Whereas with the dozens of channels you could be there a while.
OTOH there should be an EPG of some kind, to show you what's on all the channels at once. Then you know that not only is there nothing on now, there's nothing on for the near future either.
Not sure, but I do notice that our pictures are rather clearer in digital.
What's especially good is a PVR - one recording in digital. Means watching time-shifted programs has no loss in quality, unlike VHS. Since we watch most stuff like that, that's a significant gain.
(I discovered the other week you can get PVRs which record from an analogue input, which is just barking - I wondered why the quality was so low on the one I was watching)
It's not 'poorer' performance as such, just 'different' performance. The TV responds to the remote channel change command more or less instantly, as it always did. What is different is that with the older analogue tuners, all that was required to bring them to a new channel, was that the local oscillator frequency needed to be made to change, as each channel was on a discrete frequency. That was a straightforward and quick thing for the circuitry to achieve. With a digital tuner however, it's rather more complex than that. First, the system control micro needs to determine if the requested new channel is in the same multiplex as the one currently being watched. If it isn't, then firstly, the analogue front end of the tuner needs to be shifted onto the frequency of the needed multiplex. Once that has occured, the data stream has to be 'listened to' until a lock is achieved on the desired channel data. Once this has occured, the data has to be decoded and processed, and then re-encoded into a format to drive the display panel. This particular series of processes may also include reformatting of the picture resolution to match the resolution of the display panel. All of this takes considerable time, and is what is responsible for the apparent delay in the response of the TV to your channel change request.
You do actually get used to waiting that couple of seconds, but it does take a while. There are many aspects of 'digital' TV which are, in my opinion, poorer than 'good' analogue TV. On the other hand, there are also aspects that are better. Having both terrestrial Freeview and Sky satellite in use in my house, I have to say that I think that the sat service is better in every way, and easily the equal of good analogue TV in just about every respect, and far superior in many. The one big failing of all digital TV, is digital cliff effect as you say, where instead of the signal degrading gracefully, it's all or nothing. Very frustrating when there is very heavy rain or snow about, or heavily ionised atmosphere when there are thunderstorms.
Drives me up the wall, pissing town = no TV, that better than a few sparkies isn't it.
I get the same way when watching a rental DVD and it freezes 20 mins from the end. Then you play the game of skipping past the bad bit with the chapters and rewinding as far as you dare to try to lose as little as possible. Much better than VHS eh?
All this is more down to design than the technology involved. The end user experience often doesnt get enough attention at the design stage imho.
Even the digital dropouts are down to design, the transmission powers have been chosen to give the level of dropouts you experience. After DSO higher powers should be in use, and the issue should to a large extent go away.
This is simply not true, the tasks you describe are trivial and the whole operation could easily be done in under a second. It is not an 'apparent' delay, it is piss poor performance caused by poor design.
I've always felt that was also true of instructions, which often appear to have been written by people familiar with the equipment, rather than completely new users, for which the instructions are obviously intended. It's as if they were never field-trialed with the general public at all.
Instructions are generally written by technical authors who have been "contaminated" by prolonged exposure to technology and hence will find in it difficult to write for the normal user.
Hi-tech products generally don't have extensive trials these days - the pace of innovation is such that spending a month or two doing detailed user trials it seen as enough to lose any technical edge a product may have.
It's a fact of life with this type of multiplexed system. The fact that the output is delayed compared to analogue give the clue.
Not sure what you mean.
You make it sound like the original analogue channels aren't on FreeView? Or that in the 'golden' days there were only 'good' progs on? My feeling is that in those days we were grateful for anything...
Well, I can see the main London TV transmitter mast from this window. And despite having a decent aerial set up, never got a perfect picture from CH5. And under certain atmospheric conditions had problems with BBC2.
My FreeView setup gives none of the problems you describe. Or at least not with a good STB. With some of these costing so little I'd guess you get what you pay for.
How often are key (full) frames delivered over a typical DTV channel? The TV needs to wait for a key frame before it can display the picture from cold. Apart from that, I would have thought most other operations how have been completed in less than a second combined.
SKY HD takes about two seconds to change channel. It is very difficult to be any quicker because of the requirement to buffer enough data to actually decode a picture. MPEG2/4 only transmits full frame information every so often and you just can't get a meaningful image until you receive and decode one.
dave gurgled happily, sounding much like they were saying:
I strongly suspect that it's actually deliberate - and for a good reason.
That Sony TV years ago would have been designed for a handful of channels. Less than double figures. So one digit press, and you've got a definitive channel number.
The Freeview STB is designed for many channels - up to three digits. Press 1, and there's eleven channels you might mean. Perhaps a hundred and eleven channels. So does it change channel immediately? It may mean that you're changing channel three times before you get to the one you want.
So what they normally do - mine does, anyway (as does the TV) - is put an on-screen display (yes, immediately) showing the digit you pressed. If you press another one within a couple of seconds, it treats that as the second digit. Once you wait a couple of seconds, it treats the digits so far as the complete channel number.
Press channel up/down, and it changes immediately.
Yes, that's just the way that they have decided to take your mind off the fact that you are actually waiting whilst the new data stream is locked and decoded. Around 2 seconds is normal. As to whether they show you something - anything even - whilst you are waiting is a lottery. Most STBs are better in this respect than TV sets with built in Freeview. I expect that the OP's TV responds pretty much instantly to say the "MUTE" button, as he is used to on his old set, and was expecting on this one.
If it's something that you think might bother you, then probably worth checking when in the showroom picking out a new set. On a slightly different tack, always make sure that you are seeing a 'standard' Freeview-resolution picture in the shop. Most now show only HD or a Blu Ray player, and I know many people who have bought a new LCD TV, got it home, and been most disappointed with the performance when seeing it operating in 'standard' - i.e. non-native - resolution. Comet, at least my local mega store, to their credit *do* show them as you're gonna see them on your home Freeview signals, having a separate demo section to show you what HD looks like.
The tasks are not trivial for a processor that's doing lots of things at once. It is also necessary for the processor to wait until it receives and decodes a full data frame before it can begin processing the signals into something that can be sent to the display. How do you think that they manage to pack all of those different channels into the same space that a few analogue channels occupied ? They do it by multiplexing the signals together, and adding robust encoding algorithms to take care of the inevitable lost data that will occur. Decoding these alone is far from a 'trivial' task. They also don't broadcast individual frames, as they did with analogue. Only 'difference' signals between frames are broadcast for the most part, so there is a delay whilst a full frame is waited for to get the initial lock.
Do you honestly believe that every manufacturer of TV sets world wide, has lost the ability to design ones as good as their predecessors ? It is the bad system that gives rise to the 'poor' performance. The set designers are merely doing the best they can with that system.
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