SPDIF delay question.
 

You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.
Any recommendations, that don't include listening to the TV speakers?
Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

--
Eiron.

SPDIF delay question.
 

"Eiron" wrote in message
...
You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.
Any recommendations, that don't include listening to the TV speakers?
Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

--
Eiron.


Sorry, not an answer to your question, but I have the opposite - I need to
delay the video :-) I started thinking about if it was possible, but then
came to the conclusion even if I could manage to sync sound and pictures at
one point, it would probably still drift over time because there isn't a
master clock controlling the two.... thoughts anyone?

TW.

SPDIF delay question.
 

"Tex Wade"

Sorry, not an answer to your question, but I have the opposite - I need to
delay the video :-) I started thinking about if it was possible, but then
came to the conclusion even if I could manage to sync sound and pictures
at one point, it would probably still drift over time because there isn't
a master clock controlling the two.... thoughts anyone?



** Every foot you move closer or further away from the screen means a
1millisecond error in the timing.

Same goes for real people speaking too.

How can we ever solve this dilemma ????



....... Phil

SPDIF delay question.
 

Tex Wade wrote:
"Eiron" wrote in message
...
You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.
Any recommendations, that don't include listening to the TV speakers?
Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

--
Eiron.


Sorry, not an answer to your question, but I have the opposite - I need to
delay the video :-) I started thinking about if it was possible, but then
came to the conclusion even if I could manage to sync sound and pictures at
one point, it would probably still drift over time because there isn't a
master clock controlling the two.... thoughts anyone?

TW.



I find that the best way to change the sync between sound and vision on
digital TV is to switch to another channel for a few moments, then back
again. The sync relationship will be changed. Do that a few times and at
some point you will likely end up with barely adequate sync.

I guess, though that it would not be difficult to make a box with a
couple of bucket brigade delays in - one each for video and audio. A
single rotary knob could adjust the delay in each with max video delay
at the left and max sound delay on the right. For digital TV as it is at
the moment, a 10 second range should just about cover it.

d

SPDIF delay question.
 

In article , Tex Wade
tex.wade@ntl.? scribeth thus

"Eiron" wrote in message
...
You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.
Any recommendations, that don't include listening to the TV speakers?
Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

--
Eiron.


Sorry, not an answer to your question, but I have the opposite - I need to
delay the video :-) I started thinking about if it was possible, but then
came to the conclusion even if I could manage to sync sound and pictures at
one point, it would probably still drift over time because there isn't a
master clock controlling the two.... thoughts anyone?

TW.



Are you trying to do something along the lines of listen to a radio
simulcast on TV?..

If so the TV sound is at a higher bit rate that the excuse for DAB
radio.

Also in the UK the sound and picture often don't marry up due to the
**** poor standards of broadcasting these days!..
--
Tony Sayer

SPDIF delay question.
 

Don Pearce wrote:

I find that the best way to change the sync between sound and vision on
digital TV is to switch to another channel for a few moments, then back
again. The sync relationship will be changed. Do that a few times and at
some point you will likely end up with barely adequate sync.
d

I've noticed that too. Any idea why it happens?
Roger Thorpe

SPDIF delay question.
 

"tony sayer" wrote in message
...

Are you trying to do something along the lines of listen to a radio
simulcast on TV?..

If so the TV sound is at a higher bit rate that the excuse for DAB
radio.

Irrelevant. There's no such thing as a "simulcast" anymore, the processing
delays inherent in digital broadcasting make it impossible. My guess was
that the OP was using a digital audio output from his TV to connect to an AV
amplifier. In which case he should complain to the manufacturer of the TV.
Or possibly there is a delay adjustment lurking in the menu of one or the
other.


Also in the UK the sound and picture often don't marry up due to the
**** poor standards of broadcasting these days!..
--

There must be something wrong with my Sky+ set-up as I hardly ever get
lip-sync errors. On the very rare occasions when I get them when playing
back a recording, pausing and then unpausing the playback cures the problem.

David.

SPDIF delay question.
 

"David Looser"

My guess was that the OP was using a digital audio output from his TV to
connect to an AV amplifier. In which case he should complain to the
manufacturer of the TV.


** This lick explains what the dopey OP is likely on about:

http://www.audioholics.com/education...xt-big-feature



....... Phil

SPDIF delay question.
 

In article ,
Eiron wrote:
You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.
Any recommendations, that don't include listening to the TV speakers?

If you route the signal through the TV and use the line output to feed the
external amp this should give the required delay. Or at least mine does.

Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

--
*Prepositions are not words to end sentences with *

Dave Plowman London SW
To e-mail, change noise into sound.

SPDIF delay question.
 

Dave Plowman (News) wrote:

If you route the signal through the TV and use the line output to feed the
external amp this should give the required delay. Or at least mine does.

It seems to help but my TV doesn't output 5.1, only downmixed stereo
(which includes Prologic.)

--
Eiron.

SPDIF delay question.
 

Eiron wrote:

Dave Plowman (News) wrote:

If you route the signal through the TV and use the line output to feed
the
external amp this should give the required delay. Or at least mine does.


It seems to help but my TV doesn't output 5.1, only downmixed stereo
(which includes Prologic.)

I think a lot of recievers will add delay for you. The first one to come
up on the Superfi website (Onkyo HTR508 at 169 ukp) will give you up to
100 milliseconds. I'm sure fancier models will too.
see "advanced setup" on
http://www.superfi.co.uk/extras/Onky...508-manual.pdf

Roger Thorpe

SPDIF delay question.
 

Phil Allison wrote:
"David Looser"

My guess was that the OP was using a digital audio output from his TV to
connect to an AV amplifier. In which case he should complain to the
manufacturer of the TV.


** This lick explains what the dopey OP is likely on about:

http://www.audioholics.com/education...xt-big-feature

Thanks Phil. That useful link lists some AV receivers with a digital delay.
Just the excuse to get rid of the nasty Sherwood amp and get a nice Yamaha.

From the Yamaha RX-V1400 manual
"... to delay the sound output and synchronize it with the video image.
This may be necessary when using certain LCD monitors or projectors.
Choices: 0 to 240 (ms)"

Or I could just put the speakers at the bottom of the garden. :-)

--
Eiron.

SPDIF delay question.
 

Eiron wrote:

I need to add a delay to my digital audio to sync it with the digital TV.

http://www.felston.com

--
Adrian C

SPDIF delay question.
 

In article , David Looser
scribeth thus
"tony sayer" wrote in message
...

Are you trying to do something along the lines of listen to a radio
simulcast on TV?..

If so the TV sound is at a higher bit rate that the excuse for DAB
radio.

Irrelevant. There's no such thing as a "simulcast" anymore, the processing
delays inherent in digital broadcasting make it impossible.

Yes fair enough;!..

My guess was
that the OP was using a digital audio output from his TV to connect to an AV
amplifier. In which case he should complain to the manufacturer of the TV.
Or possibly there is a delay adjustment lurking in the menu of one or the
other.


Don't know if they do that..

Also in the UK the sound and picture often don't marry up due to the
**** poor standards of broadcasting these days!..
--

There must be something wrong with my Sky+ set-up as I hardly ever get
lip-sync errors. On the very rare occasions when I get them when playing
back a recording, pausing and then unpausing the playback cures the problem.

;!...
David.



--
Tony Sayer

SPDIF delay question.
 

Eiron wrote:

You know how it goes. You have to replace one thing, then nothing else
works quite right, so you end up replacing everything else....

I need to add a delay to my digital audio to sync it with the digital TV.

Dare one ask why ?


Any recommendations, that don't include listening to the TV speakers?
Are there AV amps with variable delay on the SPDIF (coax or optical)
inputs? Standalone boxes? Or just build one with a couple of ICs
such as http://focus.ti.com/docs/prod/folder...t/tpa5052.html ?

Input format I2S (standard DSP I/F) not SPDIF.

You'll need to design a complete unit to use that and no I can't think of
anything handy to do the job.

Analog signal path maybe ?

Graham

SPDIF delay question.
 

Eiron wrote:

Dave Plowman (News) wrote:

If you route the signal through the TV and use the line output to feed the
external amp this should give the required delay. Or at least mine does.

It seems to help but my TV doesn't output 5.1, only downmixed stereo
(which includes Prologic.)

Why doesn't it work properly in the first place ?

Take it back for a refund ?

Graham

SPDIF delay question.
 

Eiron wrote:

From the Yamaha RX-V1400 manual
"... to delay the sound output and synchronize it with the video image.
This may be necessary when using certain LCD monitors or projectors.
Choices: 0 to 240 (ms)"

Shame it doesnt go negative too ! ;~)

Graham

SPDIF delay question.
 

Eeyore wrote:

Dare one ask why ?

This is a consequence of complicated video signal processing inside flat
panel televisions - the picture takes more time to display than the
moment the matching sound comes to the speakers. Normally for a internal
video source, the sound has to be thus delayed to match the picture.

If an external source like a set top box, or DVD is used - and
pre-display audio is routed to an external amp/speaker system then lip
sync is an issue, unless a digital delay is added (typically receivers
have this as an option - and so do some set top boxes)

The "correct" answer is to get a proper television set with a full box
of glass and air behind it, decent contrast and dynamics, and no fancy
video processing nonsense ;-)

--
Adrian C

SPDIF delay question.
 

In article , Adrian C
wrote:


The "correct" answer is to get a proper television set with a full box
of glass and air behind it, decent contrast and dynamics, and no fancy
video processing nonsense ;-)

In time - I hope - the alternative proper answer will be that the makers of
pixel-based screens actually give them the same number and arrangement of
pixels as the images, and can update pixels without so much faffing about
'processing'. But as yet, I'd not hold my breath. Too many 'HD ready' (i.e.
not actually HD) screens to shift out of the warehouse before that...

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

SPDIF delay question.
 

"Jim Lesurf" wrote in message
...
In article , Adrian C
wrote:


The "correct" answer is to get a proper television set with a full box
of glass and air behind it, decent contrast and dynamics, and no fancy
video processing nonsense ;-)

In time - I hope - the alternative proper answer will be that the makers
of
pixel-based screens actually give them the same number and arrangement of
pixels as the images, and can update pixels without so much faffing about
'processing'. But as yet, I'd not hold my breath. Too many 'HD ready'
(i.e.
not actually HD) screens to shift out of the warehouse before that...


That would be a lot easier if all images had the same number and arrangement
of pixels, but the chance of that happening any time soon is minimal. Even
with a "proper" television set with glass (but no air, the CRT contains a
vacuum) a lot of "faffing about" is needed to cope with different aspect
ratios etc.

David.

SPDIF delay question.
 

In article , David Looser
wrote:
"Jim Lesurf" wrote in message
...
In article , Adrian C
wrote:


The "correct" answer is to get a proper television set with a full
box of glass and air behind it, decent contrast and dynamics, and no
fancy video processing nonsense ;-)

In time - I hope - the alternative proper answer will be that the
makers of pixel-based screens actually give them the same number and
arrangement of pixels as the images, and can update pixels without so
much faffing about 'processing'. But as yet, I'd not hold my breath.
Too many 'HD ready' (i.e. not actually HD) screens to shift out of
the warehouse before that...


That would be a lot easier if all images had the same number and
arrangement of pixels, but the chance of that happening any time soon
is minimal.

You presume also that the entire display area, and every pixel, *must* be
used at all times. :-)

However, I draw your attention again to my use of the phrase, "in time...".
And agree that the determination of set makers and broadcasters to keep
mixing up varying numbers of pixels with pixel-based images is a PITA. As
is the poorly-thought-out ways the 'faffing' seems to be done in some
cases.

Even with a "proper" television set with glass (but no air, the CRT
contains a vacuum) a lot of "faffing about" is needed to cope with
different aspect ratios etc.

....but with an analogue CRT none of the 'faffing about' causes any addition
delays for the displayed image. One of those cases where a simple analogue
method works quite neatly. In such cases the image data isn't 'processed',
so no 'faffing' about of it is required. In principle, all that happens
with CRT is some analogue scan waveforms are altered, essentially just in
amplitude.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

SPDIF delay question.
 

"Eiron" wrote in message


You know how it goes. You have to replace one thing, then
nothing else works quite right, so you end up replacing
everything else....
I need to add a delay to my digital audio to sync it with
the digital TV. Any recommendations, that don't include
listening to the TV speakers? Are there AV amps with
variable delay on the SPDIF (coax or optical) inputs?
Standalone boxes? Or just build one with a couple of ICs such as
http://focus.ti.com/docs/prod/folder...t/tpa5052.html
?

I have a friend who had this problem and corrected it with this:

http://www.felston.com/

SPDIF delay question.
 

Arny Krueger wrote:
"Eiron" wrote in message


You know how it goes. You have to replace one thing, then
nothing else works quite right, so you end up replacing
everything else....
I need to add a delay to my digital audio to sync it with
the digital TV. Any recommendations, that don't include
listening to the TV speakers? Are there AV amps with
variable delay on the SPDIF (coax or optical) inputs?
Standalone boxes? Or just build one with a couple of ICs such as
http://focus.ti.com/docs/prod/folder...t/tpa5052.html
?

I have a friend who had this problem and corrected it with this:

http://www.felston.com/

Replacing the old AV amp with one of these
http://www.yamaha-uk.com/av_amps_rec...product_id=206
seems to be the easiest solution with the highest WAF.

Most modern amps seem to have lip-sync delay built in.
It's just not something you think about until your CRT TV dies.

--
Eiron.

SPDIF delay question.
 

In article , Eiron

wrote:

Most modern amps seem to have lip-sync delay built in. It's just not
something you think about until your CRT TV dies.

For me, it is the other way around. Having thought about the lip synch
problems, I decided to stay with CRT. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

SPDIF delay question.
 

"Jim Lesurf" wrote in message
...

You presume also that the entire display area, and every pixel, *must* be
used at all times. :-)

No I'm not, quite the opposite.

...but with an analogue CRT none of the 'faffing about' causes any
addition
delays for the displayed image. One of those cases where a simple analogue
method works quite neatly.

Only if that option exists. DVD players and DVB boxes can optionally convert
16:9 material to either "pan & scan" or letterboxed 4:3, This is a digital
process. I do agree that this is performed fast enough not to cause lip-sync
problems, but it is very definitely "faffing about".

The letterbox option *can* be acheived simply by reducing the vertical scan
amplitude, but only a minority of 4:3 TV sets have that facility.

In such cases the image data isn't 'processed',
so no 'faffing' about of it is required. In principle, all that happens
with CRT is some analogue scan waveforms are altered, essentially just in
amplitude.

When done by the TV, yes. When done in the DVD player or DVB box, no.

David.

SPDIF delay question.
 

Jim Lesurf wrote:
In article , Eiron

wrote:

Most modern amps seem to have lip-sync delay built in. It's just not
something you think about until your CRT TV dies.

For me, it is the other way around. Having thought about the lip synch
problems, I decided to stay with CRT. :-)

Slainte,

Jim


Not an answer I'm afraid Jim. I have CRT and lip sync problems. My
answer is to give up and listen to records. TV programmes are a total
disgrace these days.

d

SPDIF delay question.
 

In article , David Looser
wrote:
"Jim Lesurf" wrote in message
...

You presume also that the entire display area, and every pixel, *must*
be used at all times. :-)

No I'm not, quite the opposite.

OK. Then given a display with a number of pixels to match the highest
definition in use, you could choose to use a subset for low definitions,
and then no processing of the image data would be required.


...but with an analogue CRT none of the 'faffing about' causes any
addition delays for the displayed image. One of those cases where a
simple analogue method works quite neatly.

Only if that option exists.

....as is true for anything. I agree, though, that if you don't have CRT,
then you can't use it. :-) Doesn't make my point invalid, though.


DVD players and DVB boxes can optionally convert 16:9 material to either
"pan & scan" or letterboxed 4:3, This is a digital process. I do agree
that this is performed fast enough not to cause lip-sync problems, but
it is very definitely "faffing about".

....and you are referring to the source behaviour, not the display.

With a CRT in principle all you have to do is allow the CRT to switch scan
width. No need for any 'pan and scan' or 'letterbox' processing by either
source or display.

The letterbox option *can* be acheived simply by reducing the vertical
scan amplitude, but only a minority of 4:3 TV sets have that facility.

In such cases the image data isn't 'processed', so no 'faffing' about
of it is required. In principle, all that happens with CRT is some
analogue scan waveforms are altered, essentially just in amplitude.

When done by the TV, yes. When done in the DVD player or DVB box, no.

I had thought we had been discussing lip synch delays caused by *displays*.
For fairly obvious reasons, if a source like a DVD player or tuner has to
have a process delay for the image it can easily then apply a similar delay
to the sound. This just requires the designer to know what they are doing.
However when the display has a vision delay, the designer may have no
control over the sound path from an external source feeding video to the
display.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

SPDIF delay question.
 

Don Pearce wrote:

TV programmes are a total disgrace these days.

Like "Britain's Got Talent" ? and "America's Stupidest Police Chases".God
preserve us.

The new Dr Who hasn't been too bad though, shame they hads to dumb down
Donna ? so she sounded like a halfwit though. Must be the need to appeal to
the chavs and general low-life. She'd have been seriously HOT otherwise.

Graham

SPDIF delay question.
 

Eeyore wrote:

Don Pearce wrote:

TV programmes are a total disgrace these days.

Like "Britain's Got Talent" ? and "America's Stupidest Police Chases".God
preserve us.

The new Dr Who hasn't been too bad though, shame they hads to dumb down
Donna ? so she sounded like a halfwit though. Must be the need to appeal to
the chavs and general low-life. She'd have been seriously HOT otherwise.

Graham


Dr. Who is genuine quality. Well written and produced but unfortunately
with some serious over-acting from Ms Tate. I never seem to be in to see
it on TV, but iPlayer is very good.

d

SPDIF delay question.
 

In article , Don
Pearce
wrote:
Jim Lesurf wrote:
In article , Eiron
wrote:

Most modern amps seem to have lip-sync delay built in. It's just not
something you think about until your CRT TV dies.

For me, it is the other way around. Having thought about the lip synch
problems, I decided to stay with CRT. :-)


Not an answer I'm afraid Jim. I have CRT and lip sync problems. My
answer is to give up and listen to records. TV programmes are a total
disgrace these days.

I occasionally notice lip synch problems on DTTV broadcasts, but it seems
rare in my experience. Mind you, my eyesight isn't marvellous... and when I
use a DTTV box to pick up R3/4 I'm not looking. :-)

Can't comment on satellite TV as I don't have a way to receive it.

What DTTV RX are you using? What stations?

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

SPDIF delay question.
 

"Jim Lesurf" wrote in message
...
In article , David Looser
wrote:
"Jim Lesurf" wrote in message
...


With a CRT in principle all you have to do is allow the CRT to switch scan
width. No need for any 'pan and scan' or 'letterbox' processing by either
source or display.

In principle yes, I'm talking about what actually happens, not what is
possible. Since the end of 405-line transmissions TV sets (as opposed to
computer monitors) have never had switching for horizontal scan frequency or
width. Quite a lot can switch the vertical frequency between 50 and 60Hz and
a few have a vertical scan amplitude switching for letterbox presentation of
widescreen material.


I had thought we had been discussing lip synch delays caused by
*displays*.
For fairly obvious reasons, if a source like a DVD player or tuner has to
have a process delay for the image it can easily then apply a similar
delay
to the sound. This just requires the designer to know what they are doing.
However when the display has a vision delay, the designer may have no
control over the sound path from an external source feeding video to the
display.


Well we were, I just made the point that just because you are watching on a
CRT that doesn't mean there isn't any "faffing about". Widscreen CRT TV's
all have digital processing to cope with various aspect ratios etc.

But it isn't the faffing about needed to convert the pixel number/layout
(which is in effect standards conversion) that causes the long delays that
cause lip-sync problems, rather that is due to more fundamental aspects of
the way flat-screen displays work.

David.

SPDIF delay question.
 

Jim Lesurf wrote:
In article , Don
Pearce
wrote:
Jim Lesurf wrote:
In article , Eiron
wrote:

Most modern amps seem to have lip-sync delay built in. It's just not
something you think about until your CRT TV dies.
For me, it is the other way around. Having thought about the lip synch
problems, I decided to stay with CRT. :-)


Not an answer I'm afraid Jim. I have CRT and lip sync problems. My
answer is to give up and listen to records. TV programmes are a total
disgrace these days.

I occasionally notice lip synch problems on DTTV broadcasts, but it seems
rare in my experience. Mind you, my eyesight isn't marvellous... and when I
use a DTTV box to pick up R3/4 I'm not looking. :-)

Can't comment on satellite TV as I don't have a way to receive it.

What DTTV RX are you using? What stations?

Slainte,

Jim


Two of them - one is a Panasonic TU-CT30 and the other is unaccountably
shy and has no name. The big chip is by Phillips. Ought to be good
though - I think I paid all of £20 in Asda for it.

d

SPDIF delay question.
 

In article , David Looser
wrote:
"Jim Lesurf" wrote in message
...

With a CRT in principle all you have to do is allow the CRT to switch
scan width. No need for any 'pan and scan' or 'letterbox' processing
by either source or display.

In principle yes, I'm talking about what actually happens, not what is
possible. Since the end of 405-line transmissions TV sets (as opposed to
computer monitors) have never had switching for horizontal scan
frequency or width.

Eh? My CRT TV switches both. It switches between 16:9 and 4:3 - by altering
the horizontal scan width. It switches also for PAL/NTSC. No idea where you
got the idea that CRT TV "never had" this after 405 line. Not all do, I
guess, but I doubt my set is unique!

Quite a lot can switch the vertical frequency between 50 and 60Hz and a
few have a vertical scan amplitude switching for letterbox presentation
of widescreen material.

Yes. My TV can also switch scaling for something like 14:9 letterboxed.
Though these days I only notice this on a weirder channel like UKTV History
where they seem unable to bother to transmit 16:9 for some odd reason.


I had thought we had been discussing lip synch delays caused by
*displays*. For fairly obvious reasons, if a source like a DVD player
or tuner has to have a process delay for the image it can easily then
apply a similar delay to the sound. This just requires the designer
to know what they are doing. However when the display has a vision
delay, the designer may have no control over the sound path from an
external source feeding video to the display.


Well we were, I just made the point that just because you are watching
on a CRT that doesn't mean there isn't any "faffing about". Widscreen
CRT TV's all have digital processing to cope with various aspect ratios
etc.

You classify operating two or three analogue switches for the two scan
waveforms as "digital processing" in the same sense as the digital domain
*image* processing that pixel displays carry out? Can't say that treating
those as being the same makes much sense to me. Partilularly as I'm not
clear that much "digital" would be needed to switch aspects and scan rates
on a CRT TV.

But it isn't the faffing about needed to convert the pixel number/layout
(which is in effect standards conversion) that causes the long delays
that cause lip-sync problems, rather that is due to more fundamental
aspects of the way flat-screen displays work.

That may be so, if you mean how the makers have *designed* them to work.
Including the use of numbers of pixel rows/columns that don't match the
image, and the manner in which they address/latch the pixels. Problem here
is that they started off making computer monitors (primarily to USA
expectations) and then have simply applied the same methods to TV. Alas, in
TV the requirements differ from general computer use. But as I said, I
suspect in time the makers will make what they'll announce as "spectacular
breakthoughs" when they get around to making displays actually with the
specific TV systems in mind. :-)

Slainte,

Jim

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SPDIF delay question.
 

In article , Jim Lesurf
scribeth thus
In article , Don
Pearce
wrote:
Jim Lesurf wrote:
In article , Eiron
wrote:

Most modern amps seem to have lip-sync delay built in. It's just not
something you think about until your CRT TV dies.

For me, it is the other way around. Having thought about the lip synch
problems, I decided to stay with CRT. :-)


Not an answer I'm afraid Jim. I have CRT and lip sync problems. My
answer is to give up and listen to records. TV programmes are a total
disgrace these days.

I occasionally notice lip synch problems on DTTV broadcasts, but it seems
rare in my experience. Mind you, my eyesight isn't marvellous... and when I
use a DTTV box to pick up R3/4 I'm not looking. :-)

Can't comment on satellite TV as I don't have a way to receive it.

Why not?, some lump of granite in the way...

What DTTV RX are you using? What stations?

Slainte,

Jim


--
Tony Sayer

SPDIF delay question.
 

In article , tony sayer

wrote:
In article , Jim Lesurf
scribeth thus


Can't comment on satellite TV as I don't have a way to receive it.

Why not?, some lump of granite in the way...

I wouldn't call our neighbour's house a "lump of granite". :-) But it may
well be in the way...

That said, I was referring to not having any dish or sat RX. But if you
want to let me have a free dish and freesat RX to give it a try, let me
know. ;-

Slainte,

Jim

--
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SPDIF delay question.
 

In article , Don
Pearce
wrote:

Not an answer I'm afraid Jim. I have CRT and lip sync problems. My
answer is to give up and listen to records. TV programmes are a total
disgrace these days.

I occasionally notice lip synch problems on DTTV broadcasts, but it
seems rare in my experience. Mind you, my eyesight isn't marvellous...
and when I use a DTTV box to pick up R3/4 I'm not looking. :-)

What DTTV RX are you using? What stations?

Two of them - one is a Panasonic TU-CT30 and the other is unaccountably
shy and has no name. The big chip is by Phillips. Ought to be good
though - I think I paid all of £20 in Asda for it.

I wonder if this depends on the RX. Apart from one or two (i.e. rare)
occasions I haven't noticed lip synch problems using either a Nokia 221T
DTTV box scart-feeding a CRT, or using a Panasonic DVD recorder with
inbuilt DTTV tuner. Alternatively, it may be that I'm just very aware of
the problem due to my lousy eyesight.

Only time I normally notice lip synch offsets is if I'm looking at video
from the Panasonic recorder's tuner to setup a recording, but am still
listening to the Nokia! But hardly surprising that two RXs have different
process delays.

I do also have a Philips DTTV box. But I just use that as a sound tuner
tfor BBC radio to go with the audio system in the dining room (where I also
keep my computer and so type - as now). So lip synch isn't an issue in that
case.

Slainte,

Jim

--
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SPDIF delay question.
 

Jim Lesurf said:


Yes. My TV can also switch scaling for something like 14:9 letterboxed.
Though these days I only notice this on a weirder channel like UKTV History
where they seem unable to bother to transmit 16:9 for some odd reason.

It's the second-hand programmes they buy from boot sales.

The test cards back, yippee
http://www.digitalspy.biz/forums/sho...d.php?t=728920

--
Ken
Contribute to: www.audiophilewiki.org

SPDIF delay question.
 

"Jim Lesurf" wrote in message
...

Eh? My CRT TV switches both. It switches between 16:9 and 4:3 - by
altering
the horizontal scan width. It switches also for PAL/NTSC. No idea where
you
got the idea that CRT TV "never had" this after 405 line. Not all do, I
guess, but I doubt my set is unique!

The widescreen sets that I have experience of switch between 16:9 and 4:3 by
time-compressing 4:3 video in the digital process area rather than altering
the scan width. Once the digital box is present it's cheaper to do
it that way. But if your set does it by altering the scan width then clearly
not *all* do it digitally. OK, I'll rephase my remark as "Since the end of
405-line transmissions 4:3 TV sets (as opposed to computer monitors) have
never had switching for horizontal scan frequency or width".

Switching between PAL & NTSC doesn't require any change to the horizontal
scan, only the switch between 50 & 60 Hz vertical scan.

Quite a lot can switch the vertical frequency between 50 and 60Hz and a
few have a vertical scan amplitude switching for letterbox presentation
of widescreen material.


You classify operating two or three analogue switches for the two scan
waveforms as "digital processing" in the same sense as the digital domain
*image* processing that pixel displays carry out?

I certainly do not! By digital processing I mean that the image shape is
changed by manipulating the image data. The video processing (colour
decoding, Y/C delay equalisation etc.) has been done digitally in all but
the cheapest sets for quite a few years now, so it doesn't add much to the
cost
of that to add image size/shape conversion as well.


Can't say that treating
those as being the same makes much sense to me.

It wouldn't to me either, if that was what I meant.

Partilularly as I'm not
clear that much "digital" would be needed to switch aspects and scan rates
on a CRT TV.

It's not "needed" it's just cheaper, as any switching associated with the
horizontal scan is expensive.

But it isn't the faffing about needed to convert the pixel number/layout
(which is in effect standards conversion) that causes the long delays
that cause lip-sync problems, rather that is due to more fundamental
aspects of the way flat-screen displays work.

That may be so, if you mean how the makers have *designed* them to work.
Including the use of numbers of pixel rows/columns that don't match the
image,

It really doesn't take long to convert from one image dimension to another,
the added delay is measured in hundreds of microseconds, not milliseconds.
You certainly won't notice that delay on lip-sync

David.

SPDIF delay question.
 

In article ,
UnsteadyKen
wrote:
Jim Lesurf said:


Yes. My TV can also switch scaling for something like 14:9
letterboxed. Though these days I only notice this on a weirder channel
like UKTV History where they seem unable to bother to transmit 16:9
for some odd reason.

It's the second-hand programmes they buy from boot sales.

Does the BBC issue letterbox 14:9 into 4:3 versions of 16:9 source
specifically for purchase at lower prices? I'm asking because some of the
programmes I've seen on UKTV History at 14:9 letterbox were, IIRC, ones
I've also seen on the BBC in 16:9... Maybe the price is per pixel. :-)

Slainte,

Jim

--
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SPDIF delay question.
 

In article , David Looser
wrote:
"Jim Lesurf" wrote in message
...

Eh? My CRT TV switches both. It switches between 16:9 and 4:3 - by
altering the horizontal scan width. It switches also for PAL/NTSC. No
idea where you got the idea that CRT TV "never had" this after 405
line. Not all do, I guess, but I doubt my set is unique!

The widescreen sets that I have experience of switch between 16:9 and
4:3 by time-compressing 4:3 video in the digital process area rather
than altering the scan width.

Erm...

For CRT that would make little sense to me. Perhaps you aren't making it
clear, or are confusing different things. Are you saying every 16:9 CRT
you've used displays 4:3 by scanning the entire 16:9 area, but puts the 4:3
image into the central portion? if so, why does it do this when fed with
something like 4:3 via SCART? Seems a weird option to me. Changing
the amplitude of the horizontal scan level seems a trivially easier
way to deal with the matter, and probably gives better results.

Mind you, I never cease to be impressed by the mindless ways some TV
manufacturers invent 'around the barn' ways to make things needlessly
complex so as to sell the result as being 'clever'. Bolony still
baffles brains, I guess, even after all these years... :-)

But so far as I can tell, when my TV CRT sees the input change to 4:3
from 16:9 there is a click as the horizontal scan amplitude alters, and the
picture falls back into the central portion of the screen. No scanning
outwith that area. Since it is a pretty standard Panasonic CRT set bought
just a few years ago I assume this is a fairly standard option. Seems like
sensible engineering to me. But if what you say is right Panasonic seem to
have shown rather more sense than other makers. Are they unique? I'd
be surprised to find they were given the simplicity of the method.

I'd agree that the levels used for the scans are set 'digitally', though,
as the widths, etc, are all accessible via onscreen menus - once you have
found the hidden service menus. :-) I assume this just means the scaling
voltages are held in something like a non-volatile RAM and then used to
reference the sizes of the analogue scan waveforms. But perhaps they do
write waveforms into RAM to get shapes right, then read the RAM series
during each line and frame. Not exactly what I'd call 'digital processing',
though. Just like using look up tables with a cheap sig gen.


Once the digital box is present it's cheaper to do it that way. But if
your set does it by altering the scan width then clearly not *all* do it
digitally.

Depends what you mean. See above. You may be confusing a 'digital box'
(i.e. external tuner) having to do the job with the display coping
with changes in aspect.


OK, I'll rephase my remark as "Since the end of 405-line
transmissions 4:3 TV sets (as opposed to computer monitors) have never
had switching for horizontal scan frequency or width".

Your point being that sets made with no provision for other than 4:3
have no provision for other than 4:3? I can see the logic of that. ;-

Slainte,

Jim

--
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