Quality of digital TV compared to analogue?
 

I've not seen this mentioned anywhere, but I wondered: does digital TV
have a better picture and sound quality than analogue TV? And is the
quality from cable better than that from an aerial?

Thanks,

Daniele
--
Apple Juice Ltd
Chapter Arts Centre
Market Road www.apple-juice.co.uk
Cardiff CF5 1QE 029 2019 0140

In article
,
D.M. Procida wrote:
I've not seen this mentioned anywhere, but I wondered: does digital TV
have a better picture and sound quality than analogue TV? And is the
quality from cable better than that from an aerial?

Depends on what you mean by "better". In the UK, digital transmissions
are the only means by which you'll see the whole of a 16:9 picture, as
the analogue transmissions chop parts of it off at the sides, so you
could say it's "better" to see the whole picture than only part of it.

Digital bit-rate compression is used, the amount varying with picture
content and the demands for bandwidth (this being shared between several
programme channels), so whatever your opinion of picture quality, it
isn't even constant. It can vary from very good to absolutely dreadful,
but this may have a lot to do with the quality of the source material,
which is extremely variable these days.

Just missing out the PAL encode/decode process by connecting your
digital receiver to your TV set as RGB by a SCART cable can make a
visible improvement to source material that is good enough to have
suffered from PAL processing in the first place, but a great deal of
material is so bad anyway that it makes no difference.

Most of the time the sound is perfectly acceptable, but if you are a
keen listener to classical music, you will notice a slight "harshness"
or "grittiness" when listening to programmes of orchestral concerts that
you won't hear if the same concert is available on an analogue channel
with NICAM sound - but then you won't see the whole picture of course.

The sound is definitely better on FM radio, and some would say the
pictures are too.

Rod.

I've not seen this mentioned anywhere, but I wondered: does digital TV
have a better picture and sound quality than analogue TV?

In your innocence you think you've asked a simple question. But asking that
question in this newsgroup is like asking Parliament to debate the
redistribution of wealth. Sides will be drawn and parties formed. Schisms will
appear.Passions will run high. The debate will rage long into the night.
Insults will be hurled and lifetime friendships will be broken. However, no
minds will be changed.

Bill

PS: digital is much better, as long as nothing on the screen moves.

D.M. Procida wrote:

I've not seen this mentioned anywhere, but I wondered: does digital TV
have a better picture and sound quality than analogue TV? And is the
quality from cable better than that from an aerial?

Digital is in some ways better, some ways worse, and in some ways
just... different!

Pros:

- The image does not have snow on it. It also does not have any
ghosting (faint duplicates of the same image, superimposed on
each other with a slight offset)

- Provided that RGB signals are used when connecting the STB to
your telly, there is no colour/luminance crosstalk (nervously
flickering colourful rainbow effects on tightly patterned shirts
etc.), and the picture will be more finely defined and detailed
(which can be clearly seen on small text captions, weather maps
etc.)

- It is possible to have true multichannel (5.1) sound.

- Widescreen (16:9) aspect ratio can be achieved with the same
(full) resolution as with the regular (4:3) aspect ratio.
(Unlike with the letterboxed 16:9 transmissions in the
analogue domain, on digital tv, potential resolution is not
being lost by transmitting black bars within the active image
area.)

- There is the potential of having better and more interactive
teletext style services.

Cons:

- While the image does not have snow on it under suboptimal
reception conditions it may still break up and get blocky -
in a rather annoying way.

- The quality of regular stereo sound may be worse than in the
analogue domain: digital tv uses MPEG-1 Audio Layer II which
is a lossy compression method, whereas NICAM transmissions
can be thought of as "purer" digital sound.

- Image is encoded into the MPEG-2 format; the same lossy
compression method as is used on DVDs. However, even though
the MPEG-2 image quality on digital tv can be _technically_
on par with a DVD disc, in practice, there is generally less
bandwidth reserved for individual DVB channels than what
would be available for the streams stored on a DVD. (This
is purely for economical reasons, in order to cram more
simultaneous programme streams into the same channel space.)
Thus, the image quality will usually be somewhat lower than
that on a DVD. What is more, some cheaper (teleshopping etc.)
channels are deliberately penny-pinching on the bandwidth and
resolution department, resulting in rather ill-looking images.

--
znark

Roderick Stewart wrote:

Most of the time the sound is perfectly acceptable, but if you are a
keen listener to classical music, you will notice a slight "harshness"
or "grittiness" when listening to programmes of orchestral concerts that
you won't hear if the same concert is available on an analogue channel
with NICAM sound - but then you won't see the whole picture of course.

And you can't use an old TV to give you NICAM sound (or use an FM radio
likewise) with Digital TV, because the latter is typically delayed by
2-3 seconds.

Just a thought; is the sound quality of Radio 3 on DTV better than the
sound quality of, say, BBC2 on DTV? If so, are they in sync? If so, a
true audiophile/anorak could use two DTV tuners when there are
simultaneous BBC2/R3 broadcasts of, eg the Promse, to optimise sound and
picture.

Stuart
--
Try stuartsmacs at dsl dot pipex dot com to email me.
The writing of Sarah Kent plumbs new depths in Shark
Infested Waters, with her ill-informed generalisations
about the subjects of Emma Rushton's 'English Clergy 92'

Bill wrote:

In your innocence you think you've asked a simple question. But asking
that question in this newsgroup is like asking Parliament to debate the
redistribution of wealth. Sides will be drawn and parties formed. Schisms
will appear.Passions will run high. The debate will rage long into the
night. Insults will be hurled and lifetime friendships will be broken.

Apart from that very last point, Daniele is used to a newsgroup like
that, so don't protect his feelings! ;-)

Stuart
--
Try stuartsmacs at dsl dot pipex dot com to email me.
The writing of Sarah Kent plumbs new depths in Shark
Infested Waters, with her ill-informed generalisations
about the subjects of Emma Rushton's 'English Clergy 92'

Jukka Aho wrote:

What is more, some cheaper (teleshopping etc.)
channels are deliberately penny-pinching on the bandwidth and
resolution department, resulting in rather ill-looking images.

1 bit per second would be more than enough for some of them. . . . .
--
Try stuartsmacs at dsl dot pipex dot com to email me.
The writing of Sarah Kent plumbs new depths in Shark
Infested Waters, with her ill-informed generalisations
about the subjects of Emma Rushton's 'English Clergy 92'

"D.M. Procida" wrote in
message
...
I've not seen this mentioned anywhere, but I wondered: does digital TV
have a better picture and sound quality than analogue TV? And is the
quality from cable better than that from an aerial?


You do not mention dish, digital TV is also brought to us by satellite.
As the BBC have decided not to give us full wide screen on analogue ie.
14x9, I use digital to give the 16x9 ratio a w/s Tv has.
I feel the picture digital wise is slightly better on satellite than
Freeview.

--
Regards,
David

Please reply to News Group.

The short answer to the original poster's question is probably that,
if there's nothing visibly wrong with your existing TV picture (no
snow, no ghosting), and you're not desperate to get 16:9 pictures,
then there's no great quality advantage to going digital. Apart from
the fact that an RGB connection from a digital source gives genuinely
cleaner looking pictures, though most people don't really notice.

As for whether cable, satellite, or FreeView looks better - it depends
on the bitrate used, and (to a _much_ lesser extent) the quality of
the box. Across all channels, you can't really say any service is
always better than the others.

Other posters have already warned you about the visible problems when
demanding source material is encoded and broadcast at too low a
bitrate. It can be shockingly bad very occasionally, but most of the
shock is in the fact that it can look like a DVD one moment, then
significantly worse the next. The other shock is that some of the most
important TV programmes are still mucked up in this way. It's never as
bad as, say, VHS - but I'd rather watch VHS sometimes because it's
consistently bad in a source _independent_ way - as opposed to say
football, where the blockiness follows the players around the pitch!
Or an old 4:3 programme on BBC2, where the picture noise means the
encoder is running out of bits all the time, and the whole picture
looks artificial, blocky or shimmery - especially on movement.

It depends so much on how critical you are, and what processing your
TV does, that you really need to go and see for yourself. Plenty of
shops demonstrate FreeView, though few do it properly. It's difficult
to mess up the connections on a TV with an integrated FreeView
adapter, so go and look at some of the IDTVs in the Sony Centre. (I'm
not suggesting you buy one - just look at the picture quality and
decide for yourself).


"Jukka Aho" wrote in message ...

Digital is in some ways better, some ways worse, and in some ways
just... different!

Pros:

- It is possible to have true multichannel (5.1) sound.

Not on terrestrial in the UK. The BBC, in their infinite wisdom,
decided that there was no call for discrete surround sound.

Cons:

- The quality of regular stereo sound may be worse than in the
analogue domain: digital tv uses MPEG-1 Audio Layer II which
is a lossy compression method, whereas NICAM transmissions
can be thought of as "purer" digital sound.

Though still lossy. Good MPEG-1 layer II shouldn't be discernably
worse. They could run it at 320kbps if there was a problem, which is
less than half the NICAM rate, would take up a tiny fraction of the RF
spectrum used by NICAM, and still sound as good. However, in this
penny pinching "give me 50 channels of crap" world it's often run at
192kbps which isn't apparently enough to deliver high quality using
the existing BBC encoders. The main BBC channels run at 256kbps, which
should be enough but maybe sometimes isn't.

- Image is encoded into the MPEG-2 format; the same lossy
compression method as is used on DVDs. However, even though
the MPEG-2 image quality on digital tv can be _technically_
on par with a DVD disc, in practice, there is generally less
bandwidth reserved for individual DVB channels than what
would be available for the streams stored on a DVD. (This
is purely for economical reasons, in order to cram more
simultaneous programme streams into the same channel space.)
Thus, the image quality will usually be somewhat lower than
that on a DVD. What is more, some cheaper (teleshopping etc.)
channels are deliberately penny-pinching on the bandwidth and
resolution department, resulting in rather ill-looking images.

I'd rather watch a snowy analogue picture that a digital picture with
annoying artefacts. Thankfully many digital pictures are free from
annoying artefacts when viewed on a bog standard CRT, and I have an
excellent analogue picture to fall back on for "difficult" material.

However, for film-shot BBC drama, it's great to have the full 16:9
frame, and the encoder doesn't seem to do quite so badly with film(ic)
material as it does with video. Maybe that's why so much video stuff
is bodged to look like film these days - a process that wrecks the
picture much more than any MPEG-2 codec could!

Cheers,
David.