Old TVs

[Dave Plowman (News)]

There is FA dynamic range on any TV stuff. Very unlikely to exceed 20dB or so - and well within the range of the system, even with that 10dB headroom. Since every programme (in theory) has levels checked at all points in its progress from original sound gathering through post production to transmission it works just fine - provided you have people who understand how to measure sound levels. Pretty well all progs will be made to the same peak levels. It's what happens to them during some automated transmission system which appears to be the problem. If anything, worse than once was the case - although commercials seem to have been tamed somewhat. With that bloody continuity announcer being the main culprit these days.

Yes. But it is artistic. ;-) And cheaper to use personal mics buried under layers of clothing than to use decent mics in a sensible position. Even before the talent does the mumbling bit.

The big snag is most of the production team never watch TV. And are so familiar with their own prog they know the words off by heart.

Decent quality at the source would be a good start. Radio manage to make panel games with perfectly good quality dialogue. So why can't TV?

[Capitol]

Yes, it's called compression. It always distorts the original source. One of the best ways to understand it is to look up the detailed analysis of HDMI systems. I'm sure there are other sources of data on digital systems if you look closely. Having worked on digital phone systems, I was always amazed that they worked as well as they do.

[T i m]

'Data compression' usually reduces bandwidth as we used to sell a 'Datamizer' that made good use of that.

Yes, I can appreciate that some digitisation can cause distortion, depending on how many bits are use for the process.

One of the modules on the courses I used to present were to do with the sampling and digital encoding and decoding of analogue data, typically as seen on CD's etc so I'm reasonably familiar with the concepts.

My question was, when you see the jerking on a video when a scene is being panned (the most typical scenario), what is it down to.

I understand it's down to insufficient bandwidth or maybe video processing power (most stressed when the frame data is completely changing and rapidly, as with a panned scene) and I tend to see it when others (typically) can't.

But then I spent a lot of time playing FPS and tuning the settings to minimise such issues. ;-)

Cheers, T i m

[Steve Walker]

While radio don't seem to bother matching the levels of guest and presenter mics - no problem when sitting listening to the radio at home, but with all the wind, engine and road noise in a car, the quiet guest can't be heard without cranking the volume up and then the presenter ends up deafeningly loud.

SteveW

[Steve Walker]

I've often wondered if it would make sense to transmit the speech and background/music as separate streams, allowing the viewers to decide how loud they need the speech to be able to hear it, while not waking the neighbours up with the sound effects! I often find myself watching films and turning the sound up and down repeatedly as scenes change from say two people talking in a room to someone bursting in and opening fire.

SteveW

[Huge]

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[Steve Walker]

Years ago (when Reservoir Dogs was released) I used to spend a lot of time programming as a hobby and had become used to spotting a line of code as I scrolled through at speed. I along with one other (who was a professional programmer) found the film unwatchable as it was jumping about as if not properly on the sprockets - the two girls with us didn't see any problem and, apparently, no-one else in the cinema complained.

SteveW

[T i m]

When I was working for Kodak as a 'walking engineer' in the City, working on their range microfilm and fiche filmers, processors and viewers, I was amazed at how some of the 'old hands' could run though a roll of microfilmed cheque's on one of the viewer / printers at a fairly high speed and stop on the right one.

Part of our job was to set the electronic brake and they were very quick to spot when it wasn't 'just right'. ;-)

I wonder if that's a mix of being familiar with the sorts of things that can go wrong (and so looking out for them) and being 'aware' of stuff around you in general?

It's the same when traveling in other peoples cars and hearing noises that I think aren't right but they might not have even heard, let alone considered or hearing noises from stuff to a level that I couldn't tolerate in my own house but they seem completely oblivious of (like a humming mains transformer or a whistling light or PSU).

I remember when colour TV's first came out and people had the colour turned right up to increase the effect! ;-)

We were invited up to dinner with the in-laws and to 'see if I could get their new soundbar working with their new 3D TV'. Once I'd sorted the soundbar (selected the right output mode on the TV and the right input port on the soundbar ) I asked if I could see the 3D TV in action. We put on the glasses and they put in DVD and they were going on about how good it looked but to me it just looked all wrong. I asked if they had some 3D material and they seemed to think that

*any* video would work? So I put on a 3D BD and they then were amazed and once they realised there really was a difference! ;-)

To be fair I think they only got it because it was offered to them at the same price of the 2D TV they wanted that was out of stock so may not have done any research into the best models (assuming they would have done that etc).

Cheers, T i m

[Dave Plowman (News)]

My original analogue mobile phone had generally miles better audio quality than most digital.

[Dave Plowman (News)]

Can't say I've ever noticed that. What radio station? Sure you're not just hearing one channel of stereo?

[Dave Plowman (News)]

Films are made for watching in the cinema. To do a totally different mix for your purpose would be fairly costly - and could only be done where the dubbing etc material still exists. It would also add to transmission costs

- and be yet something else for poor quality control to f**k up.

A decent compressor could do what you want automatically. They basically reduce the dynamic range. But their artifacts can be unpleasant to listen to.

[Steve Walker]

It is a frequent problem on Radio 4. Simply a guest that talks rather quietly compared to the host and a lack of adjustment to compensate. As I say, only a problem with the additional noise in a car.

SteveW

[Steve Walker]

Unfortunately, it seems that the cinema mix is totally unsuitable to normal TV watching then - unless you live alone and in a detached house!

SteveW

[Dave Plowman (News)]

Odd. I listen to R4 a great deal both at home and in the car, and haven't ever noticed this. It's the sound person's job to balance such things.

[Dave Plowman (News)]

Quite. It could be some do a different mix for TV, though.

But then some love the music and FX to be loud even at home. And if they were user adjustable most would soon get tired of having to fiddle all the time.

[T i m]

And that's often the thing 'these days'.

You have something that has been ideal for your needs and after a good period, fails (as such things do). So you use the opportunity to replace it, in the case of TV's, possibly with something slightly bigger and when you try you find (as you say) something you assumed was 'normal', then appears to become a Holy Grail.

Like, the sound is worse, or the startup is slower or the EPG has a smaller point size, less informative or the UI is very slow.

And then you find the thing is over-complicated with features you don't use but constantly get in the way, are un intuitive or get in the way.

Or you go to replace some white goods that you assumed were pretty std, only to find they don't make *anything* that size or format any more ... and any modern alternatives are inferior in every way (build quality, functionality, reliability), but not in what someone somewhere thought would be 'more stylish' (but isn't).

You can often see this in others when (say) helping them get and set up a new TV (something I hate doing for all the reasons stated so far) and you are just hoping the hours you spent trying to research the best option for them based on their key criteria aren't shot down by some gotcha you didn't know about or missed. ;-(

That said, *sometimes* you can get lucky and find a modern replacement that actually is better than what you had previously. ;-)

Cheers, T i m

[Chris Bartram]

Reckon so. To my ears at least, highly compresssed digital audio really mangles treble the most noticeably.

[Chris Bartram]

Yes, generally, which is why I use headphones for movies if my OH is in bed. It's impossible to get dialogue loud enough and effects quiet enough without waking her.

[Chris Bartram]

It seems to me that the broadcasters are gradually squeezing the bitrate of SD channels down: some of them are absolutely shocking, and there's still quite noticeable artefacts on HD. That's before we get into the horros of streamed content.

[The Natural Philosopher]

No, it doesnt always.

Fore axmple a ZIP file does not distiret anythung.

Lossless compression is possible, BUT for video, it takes a heck of a lot of doing and results ion a hige delay ...consider for example a systemn where you obly send CHANGES to a picture, and the actual picture itself perhaps less than once a second.

That will give you very good quality no loss low bandwith video.

Until someone does a series of rapid cuits from scene to secne, where it simply cant cope.

So in reality most stuff is good on stills and deteriorates on action, simply because the amount of *new* informations goes up as scene changing goes up.

I suspect, but do not know, that MP2 and other TV strandards are veryu accurate for stills and lose nothing, the loss being in transient stuff.

It's the same with audio. Delta modulation reduces bandwith enormously, but cannot cope with very rapid treble transients like the clash of cymbals.

I dont know exactly hwo mp2,3 and 4 do the compressing, but it doesnt have to be lossy.

It tends to GET lossy when you try and push more information - real genuine information that the receiver can't guess - down a too narrow pipe.

Bu thats how te modulatins schemas are constructed

One of the best ways to understand it is to look up the detailed