How does digital TV broadcast prevent ghosting effects?

[Joerg]

How far away is that transmitter? Curious.

Some are about 30 miles away, others about 100 miles. The one we can
still receive is roughly 10 miles west. We are up the hill from all
those so signal strength is usually very good. But sometimes the
reflected signal can be stronger than the direct path. Not a problem
with analog, you can still see the news. With DTV it's all or nothing.
The set says "reveicing data" for 10 seconds or so and then, poof, "no
signal".

 

[Jan Panteltje]

So, then, why don't they use HDTV?

Well, Netherlands (and I can only speak for them on terrestial) only
seems to broadcast SD ATM.
(Somebody correct me if it changed, I do not scan the bands every day).
That is a decision of politics, the broadcasters, I think some experiments
are going on on cable, and some HD stations from otehr parts
of Europe are relayed via cable, but, as I have no cable, I cannot tell you
anything about it.

Our system seems not to be adaptive to poor signal quality. DTV is truly
digital, either you see stunningly video or nothing at all. In that
respect analog is certainly better.

From you other posting I am amazed some clouds kill the reception.
That has never happened here receiving from one part of the country to
the other over the water even..
Thunderstorms can take out satellite however.

Same here. However, it's in the hands of companies like Dish Network.
IOW not free. OTOH we don't have to pay a TV tax.

TV is free here now too, the public broadcasters are payed from adds
and the general taxes.

But in your previous post you said HDTV is not seen over there. Is it,
or is it not?

DVB-S and DVB-S2 is *satellite*, the 'S' stands for satellite.
DVB-T and DVB-T2 are terrestial.

Probably to have the capability of extreme resolution but I don't know
for sure. In the US football and baseball fans are the ones who drive TV
and subscription sales.

The general public is just the victim of the set makers (electronic industry).
You fell for it, and will likely need to upgrade.

I believe our 1280*720 format is progressive but not sure. Anyhow, I can
only judge it as a viewer: The images are absolutely stunning. Until
multipath strikes, that is ...

I have never even noticed anything multipath related,
I am beginning to get the impression the US system sucks a lot (honestly), and that once
everybody has gone digital it will need to be upgraded to something like DVB-T2 too.

Something is wrong, you are not the only one complaining about reception problems there.
No such sounds here.

But really, the Dutch main 1,2,3 stations are free terrestial, you need a card fro
satelite, the LOCAL stations are both terrestial and on satellite and free.
Logic?
There is no logic.
That is politics.
For example I can get the local TV station, about 30 km or so away, via satellite,
and also via terrestial, both free.
Many people where I live have a dish, it is free, and cable costs money.
But I can also get say the Amsterdam area local stations via satellite....
So 'local' is Europe wide in a way.

 

[Joerg]

Well, Netherlands (and I can only speak for them on terrestial) only
seems to broadcast SD ATM.
(Somebody correct me if it changed, I do not scan the bands every day).
That is a decision of politics, the broadcasters, I think some experiments
are going on on cable, and some HD stations from otehr parts
of Europe are relayed via cable, but, as I have no cable, I cannot tell you
anything about it.

So it seems the US is ahead here

Yesterday while cooking the turkey (outside on the barbeque) I sometimes
popped in to check it out. There were at least four long HDTV
transmissions in amazing picture quality. Probably a lot more but since
I am not a sports fan I missed all of those games.

From you other posting I am amazed some clouds kill the reception.
That has never happened here receiving from one part of the country to
the other over the water even..
Thunderstorms can take out satellite however.

Well, it is said thet 8-VSB is not very multipath-tolerant and,
unfortunately, that seems to be the case. We have such extreme multipath
that sometimes signals appear on the next line (!) in analog TV. Often
the reflected signal becomes stronger than the direct one. When clouds
roll in or when the Fedex freighter lumbers into Mather Field all this
changes. In the analog signal this shows up as "pumping" but you can
still watch the programming. In digital it's poof, gone.

TV is free here now too, the public broadcasters are payed from adds
and the general taxes.

The taxes were the main reason I left NL. I met a few young gals down at
the pub above which I used to have an apartment. They were on welfare
and had no intention whatsoever to join the workforce. Because they got
so much in welfare money. Not my kind of life and I didn't want to
support such behavior.

DVB-S and DVB-S2 is *satellite*, the 'S' stands for satellite.
DVB-T and DVB-T2 are terrestial.

Doesn't answer the question

Why doesn't NL transmit terrestrial HDTV? I mean, for a soccer fan to
watch Feyenoord or another team in HDTV must be great. Same for nature
series such as Jacques Cousteau. Yesterday I saw something like that in
HD, absolutely amazing.

The general public is just the victim of the set makers (electronic industry).
You fell for it, and will likely need to upgrade.

I doubt that. There are more than a dozen formats prescribed in the
standard and the sets sold right now must be compliant with these. Also,
the set I bought has a service jack that suspiciously looks like a LAN
port. So ...

I have never even noticed anything multipath related,
I am beginning to get the impression the US system sucks a lot (honestly), and that once
everybody has gone digital it will need to be upgraded to something like DVB-T2 too.

Something is wrong, you are not the only one complaining about reception problems there.
No such sounds here.

Yep, I guess when they turn analog off there will be gnashing of teeth
and grumpy people calling their reps (which in the US works!). I don't
really care much about TV and right now it seems that in bad weather we
can at least watch our regular news while the other channels keel over.
Oh well, TV ain't that important.

But really, the Dutch main 1,2,3 stations are free terrestial, you need a card fro
satelite, the LOCAL stations are both terrestial and on satellite and free.
Logic?
There is no logic.
That is politics.
For example I can get the local TV station, about 30 km or so away, via satellite,
and also via terrestial, both free.
Many people where I live have a dish, it is free, and cable costs money.
But I can also get say the Amsterdam area local stations via satellite....
So 'local' is Europe wide in a way.

Seems to go that way here as well. On one of the DTV channels they aired
a program from Seattle yesterday. That's a 15+ hour drive from here and
only if you never stop for a meal.

 

[ChairmanOfTheBored]

Lagging is US.
It was sort of first with color (NTSC), then Europe got PAL, PAL was better.
Then Europe went digital.
US also wanted digital, and did chose a lesser system with 8VSB, putting it
more in the third world category, as you can also see from the dollar, your
current dictator, and your true elections replaced by pre-programmed Republican
voting machines ;-) Now that is funny.

The US had digital before you did, dipshit. In fact, your early digital
came from here.

General Instrument made the uplink encoders, and every satellite
set-top receiver had a GI decoder included in it.

DIGICIPHER, and DIGICIPHER II... way back in the 1990s.

8VSB wasn't until like 2004.

Get a clue, dipshit.

 

[Jan Panteltje]

Some are about 30 miles away, others about 100 miles. The one we can
still receive is roughly 10 miles west. We are up the hill from all
those so signal strength is usually very good. But sometimes the
reflected signal can be stronger than the direct path. Not a problem
with analog, you can still see the news. With DTV it's all or nothing.
The set says "reveicing data" for 10 seconds or so and then, poof, "no
signal".

I do not get it, that system SUCKS.
I am rather low, sea level, lots of houses and objects between me and my
'far away' station (say 40 miles, just checked with google maps), and
no bit errors normally.
Sometimes there was a hickup (bit-error), but picture then continued.
Lemme see
oops, my far away station no longer shows up in the channel list.
A hundred other new ones though (hardly ever use terrestial, must have been

half a year ago).

One remark: Use a good antenna.
I have one in the attic.
Oh, maybe I need to turn my antenne, there was something about going vertical polarisation.
http://home.planet.nl/~ploe2070/fmtv/dvbt/digitenne-kpntv.html
Wow, and I have it horizontal still
Still I get a hundred stations
Maybe in the weekend I will turn the antenne.

Joerg, protest with your senator, ask for the European system ;-).
LOL

 

[Jan Panteltje]

The taxes were the main reason I left NL. I met a few young gals down at

Doesn't answer the question

Well I did, I already mentioned and gave a link for all the HD satellite channels:
http://en.kingofsat.net/hdtv.php
Note that Netherlands is not among these.
Belgium, Germany, and Luxembourg are though.

 

[ChairmanOfTheBored]

Doesn't answer the question

Why doesn't NL transmit terrestrial HDTV? I mean, for a soccer fan to
watch Feyenoord or another team in HDTV must be great. Same for nature
series such as Jacques Cousteau. Yesterday I saw something like that in
HD, absolutely amazing.

They make too much money in tax revenues from the cable provider?

Broadcast is free.

But yes, HD programming is awe inspiring.

In football, one can tell how many grams of grass got embedded into the
player's jersey when his shoulder hit the deck.

Amazing.

 

[ChairmanOfTheBored]

Sometimes there was a hickup (bit-error), but picture then continued.
Lemme see

Most of that has to do with the tuner. Some brands cut out the picture
completely with drop outs in the data stream. Others show the anomalous
picture segments, and only drop out bad sound segments.

 

[Joerg]

I do not get it, that system SUCKS.
I am rather low, sea level, lots of houses and objects between me and my
'far away' station (say 40 miles, just checked with google maps), and
no bit errors normally.
Sometimes there was a hickup (bit-error), but picture then continued.
Lemme see
oops, my far away station no longer shows up in the channel list.
A hundred other new ones though (hardly ever use terrestial, must have been
One remark: Use a good antenna.

There is a huge log periodic on a mast here.

I have one in the attic.
Oh, maybe I need to turn my antenne, there was something about going vertical polarisation.
http://home.planet.nl/~ploe2070/fmtv/dvbt/digitenne-kpntv.html
Wow, and I have it horizontal still
Still I get a hundred stations
Maybe in the weekend I will turn the antenne.

You don't have mountains like we do. The highest point in NL is 322
meters (I lived on the slope of that one), out here it's over 2000
meters. Watch a Bonanza re-run and you can see the very mountains that
cause multi-path out here.

Joerg, protest with your senator, ask for the European system ;-).

Nah. But I could imagine others will. In the US most everything has to
be sold via a brand-new "must have" feature. You can't just go out and
tell people they have to buy a new TV so that additioanl tax renevue can
be generated by auctioning off some of the UHF band. You have to come up
with a compelling reason and that reason is HDTV.

 

[Joerg]

They make too much money in tax revenues from the cable provider?

Broadcast is free.

But yes, HD programming is awe inspiring.

In football, one can tell how many grams of grass got embedded into the
player's jersey when his shoulder hit the deck.

Amazing.

Yep. Yesterday I could see a documentary where they had even given the
street lamps a spit shine. Then "Ah, you guys forgot that one back
there!" What I noticed is that they squish more make-up on the
newscaster's faces. The difference is striking when they interview
someone out of the blue where there is no time for make-up. Then you can
see all the wrinkles and pimples. And guess what? IMHO David Letterman
looks a bit older in HD than he used to on our old set. But I don't
watch those shows so I have no idea how old he really is.

 

[Joerg]

Most of that has to do with the tuner. Some brands cut out the picture
completely with drop outs in the data stream. Others show the anomalous
picture segments, and only drop out bad sound segments.

I've seen that. Interpolation sets in. Then some more interpolation.
Then parts of the image kind of freeze up, later the whole image becomes
still. Switched back to the analog channel with same programming and saw
extreme ghosting and snow but still intelligible.

 

[Jan Panteltje]

I have a Hauppauge USB unit for DVB-T.
The software runs in Linux, dvbstream:

grml: ~ # /usr/local/bin/dvbstream
dvbstream v0.6 - (C) Dave Chapman 2001-2004
Released under the GPL.
Latest version available from http://www.linuxstb.org/
Usage: dvbtune [OPTIONS] pid1 pid2 ... pid8

-i IP multicast address
-r IP multicast port
-o Stream to stdout instead of network
-o:file.ts Stream to named file instead of network
-n secs Stop after secs seconds
-from n Start saving the file previously specified with -o: syntax in n minutes time
-to n Stop saving the file previously specified with -o: syntax in n minutes time
-ps Convert stream to Program Stream format (needs exactly 2 pids)
-v vpid Decode video PID (full cards only)
-a apid Decode audio PID (full cards only)
-t ttpid Decode teletext PID (full cards only)

Standard tuning options:

-f freq absolute Frequency (DVB-S in Hz or DVB-T in Hz)
or L-band Frequency (DVB-S in Hz or DVB-T in Hz)
-p [H,V] Polarity (DVB-S only)
-s N Symbol rate (DVB-S or DVB-C)

Advanced tuning options:

-c [0-3] Use DVB card #[0-3]
-D [0-4AB] DiSEqC command (0=none)

-I [0|1|2] 0=Spectrum Inversion off, 1=Spectrum Inversion on, 2=auto
-qam X DVB-T modulation - 16, 32, 64 (default), 128 or 256
-gi N DVB-T guard interval 1_N (N=32 (default), 16, 8 or 4)
-cr N DVB-T/C code rate. N=AUTO, 1_2, 2_3 (default), 3_4, 5_6, 7_8
-crlp N DVB-T code rate LP. N=AUTO, 1_2, 2_3, 3_4, 5_6, 7_8
-bw N DVB-T bandwidth (Mhz) - N=6, 7 or 8 (default)
-tm N DVB-T transmission mode - N=2 (default) or 8
-hy N DVB-T hierarchy - N=1, 2, 4, NONE (default) or AUTO
-b beep with frequency depending on signal to noise ratio (disk align)

-analyse Perform a simple analysis of the bitrates of the PIDs in the transport stream

NOTE: Use pid1=8192 to broadcast whole TS stream from a budget card

The -b option was my contribution

dvbstream works both for satelite and for terrestial, and can also stream
the content over the internet via multicast.

I use dvbstream only for terrestial, for satellite I use xdipo, it
creates a log file and writes to it anytime a bit error occurs,
with timestamp.
This is useful if you later need to edit it and re-align audio-video sync,
something that goes often wrong when editing a transport stream or mpeg2 stream
with missing packets.
ftp://panteltje.com/pub/xdipo2.jpg
I wrote xdipo, soem related programs too.
Most everything is scripted, xdipo has timers too.

 

[Joerg]

I have a Hauppauge USB unit for DVB-T.

So you watch TV via a PC? That would not fly in our living room. I am
married

But it's always good to make sure new TV sets are PC compatible so if
this while DTV stuff falls off the cliff because of multipath or
whatever people could view via the web some day.

The software runs in Linux, dvbstream:

grml: ~ # /usr/local/bin/dvbstream
dvbstream v0.6 - (C) Dave Chapman 2001-2004
Released under the GPL.
Latest version available from http://www.linuxstb.org/
Usage: dvbtune [OPTIONS] pid1 pid2 ... pid8

-i IP multicast address
-r IP multicast port
-o Stream to stdout instead of network
-o:file.ts Stream to named file instead of network
-n secs Stop after secs seconds
-from n Start saving the file previously specified with -o: syntax in n minutes time
-to n Stop saving the file previously specified with -o: syntax in n minutes time
-ps Convert stream to Program Stream format (needs exactly 2 pids)
-v vpid Decode video PID (full cards only)
-a apid Decode audio PID (full cards only)
-t ttpid Decode teletext PID (full cards only)

Standard tuning options:

-f freq absolute Frequency (DVB-S in Hz or DVB-T in Hz)
or L-band Frequency (DVB-S in Hz or DVB-T in Hz)
-p [H,V] Polarity (DVB-S only)
-s N Symbol rate (DVB-S or DVB-C)

Advanced tuning options:

-c [0-3] Use DVB card #[0-3]
-D [0-4AB] DiSEqC command (0=none)

-I [0|1|2] 0=Spectrum Inversion off, 1=Spectrum Inversion on, 2=auto
-qam X DVB-T modulation - 16, 32, 64 (default), 128 or 256
-gi N DVB-T guard interval 1_N (N=32 (default), 16, 8 or 4)
-cr N DVB-T/C code rate. N=AUTO, 1_2, 2_3 (default), 3_4, 5_6, 7_8
-crlp N DVB-T code rate LP. N=AUTO, 1_2, 2_3, 3_4, 5_6, 7_8
-bw N DVB-T bandwidth (Mhz) - N=6, 7 or 8 (default)
-tm N DVB-T transmission mode - N=2 (default) or 8
-hy N DVB-T hierarchy - N=1, 2, 4, NONE (default) or AUTO
-b beep with frequency depending on signal to noise ratio (disk align)

-analyse Perform a simple analysis of the bitrates of the PIDs in the transport stream

NOTE: Use pid1=8192 to broadcast whole TS stream from a budget card

The -b option was my contribution

dvbstream works both for satelite and for terrestial, and can also stream
the content over the internet via multicast.

I use dvbstream only for terrestial, for satellite I use xdipo, it
creates a log file and writes to it anytime a bit error occurs,
with timestamp.
This is useful if you later need to edit it and re-align audio-video sync,
something that goes often wrong when editing a transport stream or mpeg2 stream
with missing packets.
ftp://panteltje.com/pub/xdipo2.jpg
I wrote xdipo, soem related programs too.
Most everything is scripted, xdipo has timers too.

Neat! I never saw someone put that much effort into TV reception.

 

[Jan Panteltje]

So you watch TV via a PC? That would not fly in our living room. I am
married

In my view, now things are still moving, it is best to consider the 'TV"
in the living room more a 'monitor'.

That may sound cryptic perhaps, but if the 'TV" (monitor) has a DVI or HDMI
connector, then why not let the PC do the decoding, processing, recording, etc...
(after all most people will use timeshifted playback I think), and simply
update the soft if 'Yet An Other Standard' is agreed on.

There is an other issue too.
I am way into the sixties, and these days need glasses to see really sharp
close by (far away no problem).
If I sit in a living room, at say 2.5 to 3 meters from a set, it is too
far for glasses, and too close for no glasses.
What also counts is the viewing angle:

160 inch at 4 meters sharp without glasses


80 inch at 2 meters.
----------------------------------------- unsharp with or without glasses



40 inch at 1 meter
------------------------------- sharp with glasses

20 inch at 50 cm sharp with glasses
------------


So the question then becomes:
What is you 'HDTV' perception?
Test it yourself, can you see the individual pixel at your living room
viewing distance?
1) yes
2) no

if 1 you are fine.
if 2 you are not REALLY watching HD.

This is the stuff they will not tell you in a TV shop.

The alternative:
http://www1.nl2.conrad.com/conrad_n...b2c/nl_NL&fh_search=tv+bril&fh_refview=search
However this one is only 320x240.....
A HD one would work perhaps...

Special TV glasses would work too.
But note the viewing angle, to get the same at 50 cm from a 20 inch monitor,
you need a 80 inch screen at 2 meters.

My living room is not that big, and I cannot afford a 80 inch screen.
Projectors suck, and eat lightbulbs like we eat onions.

 

[Joerg]

In my view, now things are still moving, it is best to consider the 'TV"
in the living room more a 'monitor'.

That may sound cryptic perhaps, but if the 'TV" (monitor) has a DVI or HDMI
connector, then why not let the PC do the decoding, processing, recording, etc...
(after all most people will use timeshifted playback I think), and simply
update the soft if 'Yet An Other Standard' is agreed on.

There is an other issue too.
I am way into the sixties, and these days need glasses to see really sharp
close by (far away no problem).
If I sit in a living room, at say 2.5 to 3 meters from a set, it is too
far for glasses, and too close for no glasses.
What also counts is the viewing angle:

160 inch at 4 meters sharp without glasses


80 inch at 2 meters.
----------------------------------------- unsharp with or without glasses



40 inch at 1 meter
------------------------------- sharp with glasses

20 inch at 50 cm sharp with glasses
------------


So the question then becomes:
What is you 'HDTV' perception?
Test it yourself, can you see the individual pixel at your living room
viewing distance?
1) yes
2) no

if 1 you are fine.
if 2 you are not REALLY watching HD.

I can see them but barely. My wife can't.

This is the stuff they will not tell you in a TV shop.

The alternative:
http://www1.nl2.conrad.com/conrad_n...b2c/nl_NL&fh_search=tv+bril&fh_refview=search
However this one is only 320x240.....
A HD one would work perhaps...

Special TV glasses would work too.
But note the viewing angle, to get the same at 50 cm from a 20 inch monitor,
you need a 80 inch screen at 2 meters.

My living room is not that big, and I cannot afford a 80 inch screen.
Projectors suck, and eat lightbulbs like we eat onions.

Yep. When the one at our church went poof someone said "Here goes
another five hundred bucks". But with a congregation of >200 you really
don't have a choice.

 

[ChairmanOfTheBored]

So you watch TV via a PC? That would not fly in our living room. I am
married

But it's always good to make sure new TV sets are PC compatible so if
this while DTV stuff falls off the cliff because of multipath or
whatever people could view via the web some day.

A lot of modern video cards can put out HD modes now, so feeding a wide
form factor LCD FPD is no problem.

The PS3 puts out exclusively HD modes whether one is under the native
game OS (XMB) or a Linux boot.

Many folks use a PC as Myth TV front end, and feed their entire
household with it.

 

[ChairmanOfTheBored]

So the question then becomes:
What is you 'HDTV' perception?
Test it yourself, can you see the individual pixel at your living room
viewing distance?
1) yes
2) no

if 1 you are fine.
if 2 you are not REALLY watching HD.

This is the stuff they will not tell you in a TV shop.

Likely because it isn't fucking true.

I have seen grain/pixellation in the movie theaters that now have
digital projection.

Just because you can discern individual pixels on your display doesn't
negate whether it is HD or not.

 

[ChairmanOfTheBored]

I can see them but barely. My wife can't.




Yep. When the one at our church went poof someone said "Here goes
another five hundred bucks". But with a congregation of >200 you really
don't have a choice.

Large rooms are what projectors are for.

And multiply that $500 figure by ten.

 

[Joerg]

Large rooms are what projectors are for.

And multiply that $500 figure by ten.

Our church seats about 300 so it's a pretty large room. The projector
hangs from a ceiling pod about half way from the front but AFAIR the
bulb didn't cost more than $500. I thought that was already quite
outrageous. The display on the projector screen is nice, probably about
12-15ft wide.

 

[Joerg]

A lot of modern video cards can put out HD modes now, so feeding a wide
form factor LCD FPD is no problem.

Yes, even the new Dell here supposedly can do it. Still have to find out
why they didn't send the Y-cable with it that has VGA coming off one end
and HD off the other.

The PS3 puts out exclusively HD modes whether one is under the native
game OS (XMB) or a Linux boot.

Video game are something I'll probably never touch during my time on
earth. When I was a kid I built a pong game, from DTL chips pried out of
discarded mainframe boards (with my pa's blow torch). Just for the
challenge, the millisecond it worked I gave it away.

Many folks use a PC as Myth TV front end, and feed their entire
household with it.

Makes sense for the serious user but not for us. Since you seem to know
a lot about DTV, is there any comprehensive guide that shows what will
play on the digital OTA channels? Like those weekly guides that used to
be available at the supermarket? Our local paper gives one out each
weekend but the digital channels aren't in there.