Guy from "Sopranos" country, USA, needs a favor.
 

Paul D.Smith wrote:
Can you give a little more detail on what these videos actually throw out
then? I know enough to know about 625/525 and 60/50. Are you saying that
what they throw out is 525/60/PAL (and I believe UK standard is 625/50/PAL)?

To explain this, it's necessary to unpick three important
characteristics of a video signal:
1. number of lines and field rate
2. colour encoding _method_
3. colour subcarrier frequency

There are two common standard definition scanning formats: both are 2:1
interlaced. One has 525 lines per frame, 60 fields per second, the
other have 625 lines per frame, 50 fields per second.

So far so good!

There are slight variations in sync voltage and black level, which
don't cause any significant problems in practice. There are huge
differences in _broadcast_ format, which are irrelevant when we're
talking about tapes and discs.

The compatibility problem comes with the composite colour encoding
mechanism (the way of sending monochrome and colour information via a
single connection).

There are 3 methods in common use:
1. NTSC - the original composite colour encoding method - amplitude
modulated subcarrier, two colour components.
2. PAL - very similar to NTSC, but the exact choice of colour
components is slightly difference, and the phase of one of them is
flipped on alternate lines
3. SECAM - frequency modulated subcarriers (two of).

There are no significant variations in NTSC colour encoding. The
subcarrier is always 3.579545MHz.

There are a couple of variations in PAL colour encoding. In most of the
world, the subcarrier is 4.433618.75MHz, but Brazil (M/PAL) use
3.579611.49MHz while Argentina (N/PAL "combination") use 3.582056.25
(both are close to the NTSC frequency, because they're designed to fit
into a similar bandwidth).

_None_ of these are what your VCR or DVD player outputs when playing an
NTSC tape/disc on a PAL TV. Almost no UK TVs will display M/PAL
properly.

There are three different tricks in use:
1. The simplest is just to output standard NTSC. Many TVs are happy
with this, but some just aren't looking for a colour subcarrier at
3.58MHz, even if they can display 525 lines at 60Hz, so display a
slightly fuzzy black and white picture. The fuzzyness is the undecoded
colour subcarrier which looks like high frequency junk on top of the
black and white picture (because that's what it is!).
2. The next step is to output an "NTSC" colour encoded signal, but at
4.43MHz subcarrier frequency. This is called NTSC 4.43. It's totally
non standard, but some TVs can display it.
3. Even more complex is to output a "PAL" colour encoded signal at
4.43MHz. This means the colour encoding aspect is absolutely bog
standard for the UK, but it's sitting on top of a "foreign" 525-line
60Hz signal. It's totally non standard, but some TVs can display it.

Many DVD players will go the whole hog and output a 625-line 50Hz PAL
4.43MHz signal from a 525-line disc, but this conversion is messy -
unless you have the processing power and clever design of a
professional grade standards converter behind you, the results will
look a bit crappy.

If you have an RGB or component connection, then most of this is
irrelevant - you just send the 525-line signal via that connection, and
no composite colour encoding (PAL or NTSC) is used. This is the best
way to watch 525-line content on 625-line TVs, but isn't very relevant
to VHS.


If the output I describe is correct, what would be wrong with throwing
625/50/NTSC at a TV/capture card in the US? Would it not be able to handle
it? Are video capture cards really so sensitive?

Most are fine. There are two problems for the OP: getting a VCR that
will output that working in the USA, and ensuring that the 625-line
50Hz content is then converted to 525-line 60Hz before burning to DVD -
otherwise he'll have a DVD that he can't show on any US television.

(Generally, DVD players sold in the USA won't convert from 625-line to
525-line, and TVs sold in the USA won't display 625-line content at
all).

As someone with US in-laws, I have a slightly vested interest in such things

Do the conversion over here. Send them a 525-line ("NTSC" - though of
course it's not because DVDs don't have composite colour encoding - but
people use the terminology incorrectly) DVD.

You can convert from 625-line to 525-line in software. The results vary
from acceptable to crap, depending on software and content.

Cheers,
David.

Guy from "Sopranos" country, USA, needs a favor.
 

Adrian A wrote:
Ivan wrote:

I know that there's the voltage thing, but modern power supplies
should work OK even down to120 volts.. in fact to prove the point
I've been using a (cheap 'lightweight') Bush VCR906SIL which still
works quite happily when wound down to115 volts on a variac.

I have an old JVC which works perfectly at 80 volts, so I've no doubt you're
right.

Ah, but does it work properly from a 60Hz power supply? It could well
do, but "hum bars" can be a problem when using mediocre 50Hz video
equipment from a 60Hz power supply, or vicer versa.

If you superimpose a small 50Hz sine wave on top of a 50Hz video
signal, part of the screen will be a little too bright. The bright part
might move up or down slowly. You'll barely notice it.

If you superimpose a small 60Hz sine wave on top of a 50Hz video
signal, then you'll get strobing bars on the screen.

Hence slight power supply problems which you'd never notice when the
field rate matches the power supply can become quite visible when
there's a mismatch.

It shouldn't happen with half decent equipment. But someone mentioned a
£30 VCR.

Cheers,
David.

Guy from "Sopranos" country, USA, needs a favor.
 

Peptulis Amargolis wrote:
On 30 Mar 2006 14:48:25 -0800, "smitten" wrote:

I'd be happy to mail the VHS tape to somebody who could burn an MPEG-2.

I will ask my friend who has a video recorder (PAL) and a DVD
recorder. He could burn a DVD for you.

That will be a "PAL" DVD.

Most US DVD players will play it, but output a 625-line ("PAL") signal.

Almost no US TV sets will display such a signal.

It would be possible to play the DVD on a PC though, and possible to
convert the format on a PC and burn a new DVD in 525-line ("NTSC")
format.

Cheers,
David.

Guy from "Sopranos" country, USA, needs a favor.
 

wrote in message
oups.com...
Adrian A wrote:
Ivan wrote:

I know that there's the voltage thing, but modern power supplies
should work OK even down to120 volts.. in fact to prove the point
I've been using a (cheap 'lightweight') Bush VCR906SIL which still
works quite happily when wound down to115 volts on a variac.

I have an old JVC which works perfectly at 80 volts, so I've no doubt
you're
right.

Ah, but does it work properly from a 60Hz power supply? It could well
do, but "hum bars" can be a problem when using mediocre 50Hz video
equipment from a 60Hz power supply, or vicer versa.

If you superimpose a small 50Hz sine wave on top of a 50Hz video
signal, part of the screen will be a little too bright. The bright part
might move up or down slowly. You'll barely notice it.

If you superimpose a small 60Hz sine wave on top of a 50Hz video
signal, then you'll get strobing bars on the screen.

Hence slight power supply problems which you'd never notice when the
field rate matches the power supply can become quite visible when
there's a mismatch.

It shouldn't happen with half decent equipment. But someone mentioned a
£30 VCR.

The virtually standard arrangement in the UK is that the 230v mains supply
feeds a bridge rectifier and a capacitor, which supplies the primary side of
a sops power supply with around 300v DC.. I can't therefore really see that
the variation in mains frequency is going to make an awful lot of
difference, years ago I used to run a 115v NEC computer monitor in
conjunction with an auto transformer, and never experienced any problems.


Cheers,
David.

Guy from "Sopranos" country, USA, needs a favor.
 

In article ,
Ivan wrote:


The virtually standard arrangement in the UK is that the 230v mains
supply feeds a bridge rectifier and a capacitor, which supplies the
primary side of a sops power supply with around 300v DC..

That "standard arrangement" is history. The vast majority of domestic
devices use a switchmode power supply. My Thorn TX9 (1969 vintage) had one.

--
From KT24 - in drought-ridden Surrey

Using a RISC OS5 computer

Guy from "Sopranos" country, USA, needs a favor.
 

"charles" wrote in message
...
In article ,
Ivan wrote:


The virtually standard arrangement in the UK is that the 230v mains
supply feeds a bridge rectifier and a capacitor, which supplies the
primary side of a sops power supply with around 300v DC..

That "standard arrangement" is history. The vast majority of domestic
devices use a switchmode power supply. My Thorn TX9 (1969 vintage) had
one.


I don't think you've quite woken up yet Charles :0) "which supplies the
'primary side' of a *sops* power supply with around 300v DC."... *switch
operated power supply*.


--
From KT24 - in drought-ridden Surrey

Using a RISC OS5 computer

Guy from "Sopranos" country, USA, needs a favor.
 

"Ivan" wrote in message
...

"charles" wrote in message
...
In article ,
Ivan wrote:


The virtually standard arrangement in the UK is that the 230v mains
supply feeds a bridge rectifier and a capacitor, which supplies the
primary side of a sops power supply with around 300v DC..

That "standard arrangement" is history. The vast majority of domestic
devices use a switchmode power supply. My Thorn TX9 (1969 vintage) had
one.


I don't think you've quite woken up yet Charles :0) "which supplies the
'primary side' of a *sops* power supply with around 300v DC."... *switch
operated power supply*.



PS. the TX9 didn't arrive on the scene for a number of years after 1969,
you're probably thinking of the Thorn 3000 chassis (with its R2008 chopper
transistor/s) one of the first switch mode power supplies, in fact I wish I
had a £10 note for every one of those I've serviced :0)


--
From KT24 - in drought-ridden Surrey

Using a RISC OS5 computer

Guy from "Sopranos" country, USA, needs a favor.
 

Lots of detail snipped and some follow up questions.

Paul DS

There are three different tricks in use:
1. The simplest is just to output standard NTSC. Many TVs are happy
with this, but some just aren't looking for a colour subcarrier at
3.58MHz, even if they can display 525 lines at 60Hz, so display a
slightly fuzzy black and white picture. The fuzzyness is the undecoded
colour subcarrier which looks like high frequency junk on top of the
black and white picture (because that's what it is!).
2. The next step is to output an "NTSC" colour encoded signal, but at
4.43MHz subcarrier frequency. This is called NTSC 4.43. It's totally
non standard, but some TVs can display it.
3. Even more complex is to output a "PAL" colour encoded signal at
4.43MHz. This means the colour encoding aspect is absolutely bog
standard for the UK, but it's sitting on top of a "foreign" 525-line
60Hz signal. It's totally non standard, but some TVs can display it.

Umm, nothing that came with my video recorder says anything about needing
help from the TV to play an NTSC pictures, but it does, with all the clear,
precise, colour that you expect from NTSC ;-). Presumably this means that
almost all TVs will handle "NTSC-ish" pictures because I doubt my £50 video
has the processing power that you talk about below.


Many DVD players will go the whole hog and output a 625-line 50Hz PAL
4.43MHz signal from a 525-line disc, but this conversion is messy -
unless you have the processing power and clever design of a
professional grade standards converter behind you, the results will
look a bit crappy.

If you have an RGB or component connection, then most of this is
irrelevant - you just send the 525-line signal via that connection, and
no composite colour encoding (PAL or NTSC) is used. This is the best
way to watch 525-line content on 625-line TVs, but isn't very relevant
to VHS.


If the output I describe is correct, what would be wrong with throwing
625/50/NTSC at a TV/capture card in the US? Would it not be able to
handle
it? Are video capture cards really so sensitive?

Most are fine. There are two problems for the OP: getting a VCR that
will output that working in the USA, and ensuring that the 625-line
50Hz content is then converted to 525-line 60Hz before burning to DVD -
otherwise he'll have a DVD that he can't show on any US television.


I seem to recall that videos don't have 625 (or even 525) line resolution so
do they actually produce 300 (say) line pictures or do they fake up a 625
line picture? If they produce 300 line anyway, does this mean that it
should be still relatively simple to get a US video to play PAL takes
(assuming that US TVs will handle PAL-ish formats - and I thought most TVs
these days use universal chipsets).

(Generally, DVD players sold in the USA won't convert from 625-line to
525-line, and TVs sold in the USA won't display 625-line content at
all).

So although we in the UK can buy and play US DVDs, are you saying that
people in the US cannot buy UK DVDs and expect them to play?


As someone with US in-laws, I have a slightly vested interest in such
things

Do the conversion over here. Send them a 525-line ("NTSC" - though of
course it's not because DVDs don't have composite colour encoding - but
people use the terminology incorrectly) DVD.

If only my PC weren't 5 years old ;-). I was interested because having a
"will play NTSC" video, I was surprised that the reverse (play PAL in the
US) was not possible which is why I'm drilling for details. Never had to
send them anything yet but we do have friends who occasionally ask "could
you..." to which I currently answer "sorry but no".


You can convert from 625-line to 525-line in software. The results vary
from acceptable to crap, depending on software and content.

Cheers,
David.

Guy from "Sopranos" country, USA, needs a favor.
 

In article ,
Ivan wrote:


PS. the TX9 didn't arrive on the scene for a number of years after 1969,
you're probably thinking of the Thorn 3000 chassis (with its R2008
chopper transistor/s) one of the first switch mode power supplies, in
fact I wish I had a £10 note for every one of those I've serviced :0)


Yes, I was confusing my first Thorn set with the later TX9

--
From KT24 - in drought-ridden Surrey

Using a RISC OS5 computer

Guy from "Sopranos" country, USA, needs a favor.
 

"Ivan" wrote in message
...

"charles" wrote in message
...
In article ,
Ivan wrote:


The virtually standard arrangement in the UK is that the 230v mains
supply feeds a bridge rectifier and a capacitor, which supplies the
primary side of a sops power supply with around 300v DC..

That "standard arrangement" is history. The vast majority of domestic
devices use a switchmode power supply. My Thorn TX9 (1969 vintage) had
one.


I don't think you've quite woken up yet Charles :0) "which supplies the
'primary side' of a *sops* power supply with around 300v DC."... *switch
operated power supply*.




Sorry Charles brain fade! 'sops' is usually the acronym for self-oscillating
power supply.


--
From KT24 - in drought-ridden Surrey

Using a RISC OS5 computer