Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

Watching some programming, like a classical music performance where one
can see string players' bows moving, sometimes the sound is so far off
as to be quite irritating, seemingly as much as half a second or so.

I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

David Nebenzahl wrote in message
s.com...
Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

Watching some programming, like a classical music performance where one
can see string players' bows moving, sometimes the sound is so far off
as to be quite irritating, seemingly as much as half a second or so.

I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

Even on , supposed, live feeds , often lack of sync in the UK
You mention classical music. I cannot listen to proper music on any of the
UK freeview channels because of some sort of overload distortion. This is
same on 2 makes of set-top box , is it just Rowridge, IoW, transmissions/
local multipath problem to me or do others find this issue in the UK? Is
there a name for this distortion ? full orchestra with the brakes on is fine
but go forte and clipping sort of compression distortion - if only they
still had test-cards with pilot tone these days, so I could scope.
And also related, no time signals these days, no seconds of time mentioned
anywhere on digital.

On 29/01/2011 08:39, N_Cook wrote:

Even on , supposed, live feeds , often lack of sync in the UK
You mention classical music. I cannot listen to proper music on any of the
UK freeview channels because of some sort of overload distortion. This is
same on 2 makes of set-top box , is it just Rowridge, IoW, transmissions/
local multipath problem to me or do others find this issue in the UK? Is
there a name for this distortion ? full orchestra with the brakes on is fine
but go forte and clipping sort of compression distortion - if only they
still had test-cards with pilot tone these days, so I could scope.
And also related, no time signals these days, no seconds of time mentioned
anywhere on digital.

There are some articles on http://www.audiomisc.co.uk that refer to
listening of classical music via DTT and issues, though my music
interest is mainly non-proper music containing mostly triangle waves,
but you may something of interest here.

Sound on Vision
http://www.audiomisc.co.uk/HFN/SoV/soundonvision.html

iPlayer rules OK?
http://www.audiomisc.co.uk/BBC/iPlayerRulesOK/Page1.html

--
Adrian C

In article m,
David Nebenzahl wrote:
I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?

I'm in the UK, but different receivers introduce their own differing
delay. As you'd notice with two on at the same time. And this is just DTV
tuners - not complete sets which may introduce a sound delay to compensate
for that in the display technology.

What I'm not sure is if the picture is still in sync with the sound on
these units.

There have been reports here of a re-boot sorting gross sound sync
problems on some makes.

--
*Sorry, I don't date outside my species.

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

In article ,
N_Cook wrote:
You mention classical music. I cannot listen to proper music on any of
the UK freeview channels because of some sort of overload distortion.
This is same on 2 makes of set-top box , is it just Rowridge, IoW,
transmissions/ local multipath problem to me or do others find this
issue in the UK? Is there a name for this distortion ?

Must be a local to you thing. I only ever listen to TV sound through a
decent external sound system, and although there are sometimes problems,
it's not fundamental to the system. Indeed I use FreeView tuners for radio
these days.

One thing you could check is your not overloading the input to whatever
you're listening on - some STBs can supply much more output than analogue
ones, if things are peaked to 0dBFS.

--
*(on a baby-size shirt) "Party -- my crib -- two a.m

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

Dave Plowman (News) wrote in message
...
In article m,
David Nebenzahl wrote:
I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?

I'm in the UK, but different receivers introduce their own differing
delay. As you'd notice with two on at the same time. And this is just DTV
tuners - not complete sets which may introduce a sound delay to compensate
for that in the display technology.

What I'm not sure is if the picture is still in sync with the sound on
these units.

There have been reports here of a re-boot sorting gross sound sync
problems on some makes.

--
*Sorry, I don't date outside my species.

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

I use one most of the time and another to record another digital ch
concurrently off-air or for a second recorder on a few occassions. The
second one just feeds an earpiece so I can check the sound of that one
without any picture hook-up is the same as the main one with on-screen
ident, in case of r/c miskeyings. They never agree but they must each be in
sync within themselves , but not checked with 2 TVs simultaneously.

On the music distortion , there is a an UHF aerial amp in line, suppling
both set-top boxes. Sometime I will try a different one to see if it makes a
difference. Without an amp some channels become "no signal" although ok for
BBC4 , must try set-top box digital radio 3 sometime.

In article ,
N_Cook wrote:
On the music distortion , there is a an UHF aerial amp in line, suppling
both set-top boxes. Sometime I will try a different one to see if it
makes a difference. Without an amp some channels become "no signal"
although ok for BBC4 , must try set-top box digital radio 3 sometime.

I don't think anything you could do to the incoming RF data stream could
cause the problems you report. I'm in a very strong signal area as regards
UHF - I can see the Crystal Palace mast which is about 5 miles away. The
aerial fed direct to an analogue TV caused overload - but no such problems
when fed to a DTV box on trials. But of course I've not tried them all.

--
*I believe five out of four people have trouble with fractions. *

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

Dave Plowman (News) wrote in message
...
In article ,
N_Cook wrote:
On the music distortion , there is a an UHF aerial amp in line, suppling
both set-top boxes. Sometime I will try a different one to see if it
makes a difference. Without an amp some channels become "no signal"
although ok for BBC4 , must try set-top box digital radio 3 sometime.

I don't think anything you could do to the incoming RF data stream could
cause the problems you report. I'm in a very strong signal area as regards
UHF - I can see the Crystal Palace mast which is about 5 miles away. The
aerial fed direct to an analogue TV caused overload - but no such problems
when fed to a DTV box on trials. But of course I've not tried them all.

--
*I believe five out of four people have trouble with fractions. *

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


Its consistently the same , 2 different converters, 2 different aerials and
downleads.
So unlikely multipath problems which ttend th change with weather and time
of day etc. I think there is audio overload on general sound eg when there
is an argument, elevated voices and speaking at the same time - its just its
more obvious with an orchestra.

When I dig it out I will try another uhf amp, then it will be a full-on
mystery, if still the same audio problem. Never any picture problems other
than nearby motor use or very bad vehicle ignition

On 1/29/2011 5:24 AM, N_Cook wrote:
Its consistently the same , 2 different converters, 2 different aerials and
downleads.
So unlikely multipath problems which ttend th change with weather and time
of day etc. I think there is audio overload on general sound eg when there
is an argument, elevated voices and speaking at the same time - its just its
more obvious with an orchestra.

Ya know, once upon a time, "Broadcast quality" used to mean
something.

Now it appears to mean, "How much advertising revenue can we
cram into something?"

Nobody gives a **** about "doing it right" all the way down the
line from the CEO to the techs.

Jeff

David Nebenzahl wrote:
Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

Watching some programming, like a classical music performance where one
can see string players' bows moving, sometimes the sound is so far off
as to be quite irritating, seemingly as much as half a second or so.

I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?


Yeah, a good plot to get rid of over the air TV all together. Just
think about all those extra cell phones they can add to the system and
make big money! ALong with all those other services that can be added
for a fee!



Jamie

"Jeffrey Angus" wrote in message
. ..
On 1/29/2011 5:24 AM, N_Cook wrote:
Its consistently the same , 2 different converters, 2 different aerials
and
downleads.
So unlikely multipath problems which ttend th change with weather and
time
of day etc. I think there is audio overload on general sound eg when
there
is an argument, elevated voices and speaking at the same time - its just
its
more obvious with an orchestra.

Ya know, once upon a time, "Broadcast quality" used to mean
something.

Now it appears to mean, "How much advertising revenue can we
cram into something?"

Nobody gives a **** about "doing it right" all the way down the
line from the CEO to the techs.

Jeff


I think to some extent, that depends on the 'quality' of the broadcaster
involved. I watch a lot of HD transmissions on sat, and most are superb.
I've never seen a sound / vision sync problem that I can remember. However,
I also watch some of the cheapo channels, and the whole production quality
can, as you say, be very variable. On these channels, I have often seen the
sync problem, so I guess that somewhere along the line, it's caused by cheap
production techniques, or maybe something to do with the bandwidth (cost) of
the data link from the programme producer to the uplink station, or maybe
the quality (cost) of the transponder that they are renting on the sat ?

Arfa

In article m,
David Nebenzahl wrote:

Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

I'm surprised there aren't more complaints about this. Two HD
television sets connected to the same antenna system can have an audio
difference between the two. Weak signal conditions seem to be the
worst, with very obvious delay just before the picture breaks up.

There are probably several reasons for the discrepancy, but there is no
excuse. Audio-video sync shouldn't be a problem with a digital system,
but the current HD system is obviously weak in this area. Perhaps there
is a delay due to the need for error correction when signals are poor.
If so, why isn't one delayed so both audio and video are presented at
the same time? It might take some extra memory to hold delayed data,
and maybe an algorithm to shed an occasional video frame. Or is it the
other way around, with audio leading the video?

I haven't seen this mentioned in Consumer Reports television reviews, so
few of us are complaining about it!

Fred

On 1/29/2011 11:03 AM Fred McKenzie spake thus:

In article m,
David Nebenzahl wrote:

Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

I'm surprised there aren't more complaints about this. Two HD
television sets connected to the same antenna system can have an audio
difference between the two. Weak signal conditions seem to be the
worst, with very obvious delay just before the picture breaks up.

There are probably several reasons for the discrepancy, but there is no
excuse. Audio-video sync shouldn't be a problem with a digital system,
but the current HD system is obviously weak in this area. Perhaps there
is a delay due to the need for error correction when signals are poor.
If so, why isn't one delayed so both audio and video are presented at
the same time? It might take some extra memory to hold delayed data,
and maybe an algorithm to shed an occasional video frame. Or is it the
other way around, with audio leading the video?

Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
I'd say that the audio is simply sacrificed for the sake of displaying
video. When there's a marginal signal coming in, the video will continue
to be displayed, albeit with some break-up and possible freezing, while
the audio simply drops out.


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

On Jan 29, 3:36*am, Jeffrey Angus wrote:
snip
Ya know, once upon a time, "Broadcast quality" used to mean
something.

Now it appears to mean, "How much advertising revenue can we
cram into something?"

Nobody gives a **** about "doing it right" all the way down the
line from the CEO to the techs.

Jeff

It still does mean something and if you ever thought revenue WASN'T a
part of it, you're just wrong. I get to see 'broadcast quality' video
from the 60's and 70's at work and while it was good in its day, it
doesn't hold a candle to what you have now. I'm one of those 'techs'
and I can tell you we DO give a hoot about how it looks and sounds.

G²

David Nebenzahl wrote in message
.com...
On 1/29/2011 11:03 AM Fred McKenzie spake thus:

In article m,
David Nebenzahl wrote:

Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

I'm surprised there aren't more complaints about this. Two HD
television sets connected to the same antenna system can have an audio
difference between the two. Weak signal conditions seem to be the
worst, with very obvious delay just before the picture breaks up.

There are probably several reasons for the discrepancy, but there is no
excuse. Audio-video sync shouldn't be a problem with a digital system,
but the current HD system is obviously weak in this area. Perhaps there
is a delay due to the need for error correction when signals are poor.
If so, why isn't one delayed so both audio and video are presented at
the same time? It might take some extra memory to hold delayed data,
and maybe an algorithm to shed an occasional video frame. Or is it the
other way around, with audio leading the video?

Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
I'd say that the audio is simply sacrificed for the sake of displaying
video. When there's a marginal signal coming in, the video will continue
to be displayed, albeit with some break-up and possible freezing, while
the audio simply drops out.


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.


Back in the days when there were engineers , they designed a colour TV
system
In slightly degraded signal conditions you lost colour - could still follow
a film say
Worse propogation and picture became snowy - still followable
Worse and sound became noisey and syncs being lost - just about followable
Finally the sound would go

These days its all arse about face, sound is the first to go and colour is
the last to go

On Sat, 29 Jan 2011 11:22:19 -0800, David Nebenzahl wrote:

On 1/29/2011 11:03 AM Fred McKenzie spake thus:

In article m,
David Nebenzahl wrote:

Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely ****-poor.

I'm surprised there aren't more complaints about this. Two HD
television sets connected to the same antenna system can have an audio
difference between the two. Weak signal conditions seem to be the
worst, with very obvious delay just before the picture breaks up.

There are probably several reasons for the discrepancy, but there is no
excuse. Audio-video sync shouldn't be a problem with a digital system,
but the current HD system is obviously weak in this area. Perhaps
there is a delay due to the need for error correction when signals are
poor. If so, why isn't one delayed so both audio and video are
presented at the same time? It might take some extra memory to hold
delayed data, and maybe an algorithm to shed an occasional video frame.
Or is it the other way around, with audio leading the video?

Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
I'd say that the audio is simply sacrificed for the sake of displaying
video. When there's a marginal signal coming in, the video will continue
to be displayed, albeit with some break-up and possible freezing, while
the audio simply drops out.

Newest Sci-Atlanta DTVHD-DVR, TWC here. Don't notice a lot of sync
problems. Being a musician I would notice even a few milliseconds.

More problems with picture fizzle-out accompanied by audio drops and buzz
on HD channels. Signal tested recently. Found to be high-normal in the HD
range. Nothing to bitch about except when Discovery-HD fizzed and buzzed
every 10 seconds. A new DVR fixed that.



--
Live Fast, Die Young and Leave a Pretty Corpse

In article
,
wrote:
It still does mean something and if you ever thought revenue WASN'T a
part of it, you're just wrong. I get to see 'broadcast quality' video
from the 60's and 70's at work and while it was good in its day, it
doesn't hold a candle to what you have now. I'm one of those 'techs'
and I can tell you we DO give a hoot about how it looks and sounds.

It's very unlikely you are seeing broadcast electronic video from the 60s
and 70s as good as it was then. It'll have been transferred a few times as
tape formats go out of use - and the transfer equipment likely towards the
end of its life. Plus the fact that even a single generation of quad VTR
caused noticeable degradation, and most of the stuff which has been kept
will be two or more generations.

--
*If you try to fail and succeed, which have you done? *

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

On 1/29/2011 12:51 PM Meat Plow spake thus:

On Sat, 29 Jan 2011 11:22:19 -0800, David Nebenzahl wrote:

Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
I'd say that the audio is simply sacrificed for the sake of displaying
video. When there's a marginal signal coming in, the video will continue
to be displayed, albeit with some break-up and possible freezing, while
the audio simply drops out.

Newest Sci-Atlanta DTVHD-DVR, TWC here. Don't notice a lot of sync
problems. Being a musician I would notice even a few milliseconds.

OK, but how about other channels? The out-of-synch problem seems to be
the worst on a local public station that runs a mish-mosh of programming
with *extremely* low standards for any kind of production values, but
I've noticed it even on network stations (NBC, ABC, etc.) where even
speech doesn't match the speaker's lips.

More problems with picture fizzle-out accompanied by audio drops and buzz
on HD channels. Signal tested recently. Found to be high-normal in the HD
range. Nothing to bitch about except when Discovery-HD fizzed and buzzed
every 10 seconds. A new DVR fixed that.

Oddly enough, I've never experienced *any* of those problems with DTV.
Just audio drop-out, but no buzz, hum, distortion, etc.


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

On Jan 29, 4:29*pm, "Dave Plowman (News)"
wrote:
In article
,
* wrote:

It still does mean something and if you ever thought revenue WASN'T a
part of it, you're just wrong. I get to see 'broadcast quality' video
from the 60's and 70's at work and while it was good in its day, it
doesn't hold a candle to what you have now. I'm one of those 'techs'
and I can tell you we DO give a hoot about how it looks and sounds.

It's very unlikely you are seeing broadcast electronic video from
the 60s
and 70s as good as it was then. It'll have been transferred a few
times as
tape formats go out of use - and the transfer equipment likely
towards the
end of its life. Plus the fact that even a single generation of
quad VTR
caused noticeable degradation, and most of the stuff which has been
kept
will be two or more generations.

--
*If you try to fail and succeed, which have you done? *

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

It IS unlikely but I work in Hollywood and am one of the few who still
get (got?) to work on quads so it happens to be true. I was watching
the original 2" quad tape played back on an Ampex AVR-1 just a few
weeks ago. It was an NBC Danny Thomas special (low band color so there
was some moire) from 1965 with Johnny Carson, Bill Cosby, Tim Conway
and others You're also mistaken about how many generations you can go
down before you have noticeable problems. Network on air tapes were a
minimum of 3 generations down. Mind you, it's necessary to adjust
things properly unlike the newest digital machines that are close to
idiot proof but will tie you in knots with the myriad settings.

You probably never saw a Super High Band Pilot quad tape where the
time base reference was recorded analog along with the analog FM
video. Zero velocity errors as the pilot was the sample clock and any
timing errors on the video were also in the pilot so the error was
nada. That came out in the '70s along with the first 1 inch decks
which had the 'trick' video of slo-mo and still frames which were
previously unavailable to local stations. Quad died fast after that
but not until having a 20+ year run.

I was just repairing Ampex AVR-3s this afternoon.
G²

In article
,
wrote:
It's very unlikely you are seeing broadcast electronic video from the
60s and 70s as good as it was then. It'll have been transferred a few
times as tape formats go out of use - and the transfer equipment
likely towards the end of its life. Plus the fact that even a single
generation of quad VTR caused noticeable degradation, and most of the
stuff which has been kept will be two or more generations.

It IS unlikely but I work in Hollywood and am one of the few who still
get (got?) to work on quads so it happens to be true. I was watching
the original 2" quad tape played back on an Ampex AVR-1 just a few
weeks ago. It was an NBC Danny Thomas special (low band color so there
was some moire) from 1965 with Johnny Carson, Bill Cosby, Tim Conway
and others.

I started work for the BBC at their main production centre in the early
'60s in the days when some drama and LE was still live. And therefore saw
the introduction of colour in the UK from the sharp end.


You're also mistaken about how many generations you can go
down before you have noticeable problems. Network on air tapes were a
minimum of 3 generations down. Mind you, it's necessary to adjust
things properly unlike the newest digital machines that are close to
idiot proof but will tie you in knots with the myriad settings.

And you never noticed the degradation compared to live progs? With only
even one generation?

You probably never saw a Super High Band Pilot quad tape where the
time base reference was recorded analog along with the analog FM
video. Zero velocity errors as the pilot was the sample clock and any
timing errors on the video were also in the pilot so the error was
nada. That came out in the '70s along with the first 1 inch decks
which had the 'trick' video of slo-mo and still frames which were
previously unavailable to local stations. Quad died fast after that
but not until having a 20+ year run.

C-format degraded things too.

I was just repairing Ampex AVR-3s this afternoon.
G²

DigiBeta was the first tape based system I saw which in general didn't
degrade things noticeably.

--
*Why do overlook and oversee mean opposite things?

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