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s-video input / widescreen tv ?

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laurent.farcy at freesbee

Jan 20, 2003, 3:41 AM

Post #1 of 27 (4749 views)
Permalink

s-video input / widescreen tv ?

Hi all,

First I must admit what you've been doing with MythTV is quite
impressive. Here in France, we haven't even got Tivo or ReplayTV boxes.
It's been awhile since I envy you being able to enjoy DVR. And now,
thanks to you, it's available for free (at least no subscription fee).

Obviously, now, I'm thinking of building my own MythTV box and I've got
some questions I would like to get answered before starting buying and
assembling anything (I browsed the mailing list but I haven't found any
definitive answers).

1/ I've got a digital cable box I would like to be the main input for
MyhtTV. So, I guess I have to plug it to the s/video input of the tuner
card and the line in of my sound card. From what I read in the mailing
list, you have to trick in the code to select the s-video input instead
of the television for recordings. But soon the 'select your input for
recording' feature will be included ? Am I right ? By the way, if I can
be of any help for code updates...

2/ Though my cable box will be my main input, I will plug my rf antenna
to the tuner card. So next question is : does MythTV manage input
selection/switch for for live watching/pausing/forwarding ? A feature to
come maybe ?

3/ Not so many threads talk about widescreen tvs/programmes. Although,
some of you guys own one. So, to make short, my question is whether
MythTV compatible with widescreen programmes and TVs ? IMHO, 'compatible
with widescreen programmes' would mean recordings happen in anamorphic
aspect ratio (whenever the source is anamorphic) so that when you read
them you can still expand it to 16:9 (whilst it's been recorded in 4:3
anamorphic format). And 'compatible with widescreen tv' would mean you
can generate a tv-output signal which is 4:3 anamorphic so that your tv
can expand it to 16:9. Am I clear/right ?

4/ Last, I'm wondering if there's a difference in terms of quality
between tv tuner cards for video grabbing, and particularly in my case
for s-video input grabbing. The differences could be, I guess, on
maximum resolution, visual quality, widescreen handling, ... So if you
could share your experience, I would appreciate your feedback.

A lot of questions for a first post... So many thanks in advance for
your answers.

Laurent

erik_nospam.arendse at bigfoot

Jan 20, 2003, 4:01 AM

Post #2 of 27 (4725 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 11:41, Laurent Farcy wrote:
>3/ Not so many threads talk about widescreen tvs/programmes. Although,
>some of you guys own one. So, to make short, my question is whether MythTV
>compatible with widescreen programmes and TVs ? IMHO, 'compatible with
>widescreen programmes' would mean recordings happen in anamorphic aspect
>ratio (whenever the source is anamorphic) so that when you read them you
>can still expand it to 16:9 (whilst it's been recorded in 4:3 anamorphic
>format). And 'compatible with widescreen tv' would mean you can generate a
>tv-output signal which is 4:3 anamorphic so that your tv can expand it to
>16:9. Am I clear/right ?

Two seperate questions in fact:

A) does the tuner recognize the widescreen code, and can the TV output add
it to the generated signal again?
Simply stated: No. Several standards exist to signal a widescreen
transmission, first tell me which one is used by your cable box. If it has
SCART out (should have as SCART was invented by the French :-) one pin
normally is used to indicate anamorphic signal.
I know of no TV-in card which can detect that, but it would be easy to
build yourself (just connect to a LPT in-pin and read the line)
Output can be done the same way on the outgoing scart pin.
Other standards are used in the US (signal is transmitted alongside the CC
title data) and in Europe alongside the VPS/VideoText data. Detecting those
is no problem (especially when I finished subtitle support for MythTV), but
sending them on a videosignal again is (I don't know of any
software/hardware yet which can do that).

B) can you record/play anamorphic?
Yes, no problem. Anamorphic just means you squash the image into 4:3 when
transmitting it, it is only handled by the camera and the final display,
any transfer channel in between (and myhtTV in this case is just a
time-delayed transfer channel) just had to pass it along the data
unchanged. As a user-aid a 1-bit flag is included to indicate the
anamorphic format.
If you can detect the flag correctly you can even flatten the display of
the XV window on the computerscreen.

4/ Last, I'm wondering if there's a difference in terms of quality between
tv tuner cards for video grabbing, and particularly in my case for s-video
input grabbing. The differences could be, I guess, on maximum resolution,
visual quality, widescreen handling, ... So if you could share your
experience, I would appreciate your feedback.
Max resolution is fixed for any PAL or NTSC standard. You can't grab any
more lines then are transmitted, you just have to accept TV was meant for a
V screen. If you have satelite or cable, perhaps you can grab some digital
channels, they are not limited that way, but MythTV just supports analog TV
tuner cards (for now???).

Erik

laurent.farcy at freesbee

Jan 20, 2003, 4:31 AM

Post #3 of 27 (4716 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
> At 20-1-03 11:41, Laurent Farcy wrote:
>
>
> Two seperate questions in fact:
>
> A) does the tuner recognize the widescreen code, and can the TV output
> add it to the generated signal again?
> Simply stated: No. Several standards exist to signal a widescreen
> transmission, first tell me which one is used by your cable box. If it
> has SCART out (should have as SCART was invented by the French :-) one
> pin normally is used to indicate anamorphic signal.
> I know of no TV-in card which can detect that, but it would be easy to
> build yourself (just connect to a LPT in-pin and read the line)
> Output can be done the same way on the outgoing scart pin.
> Other standards are used in the US (signal is transmitted alongside the
> CC title data) and in Europe alongside the VPS/VideoText data. Detecting
> those is no problem (especially when I finished subtitle support for
> MythTV), but sending them on a videosignal again is (I don't know of any
> software/hardware yet which can do that).

I didn't know there was no standard for signaling a widescreen
transmission. Apparently, since I live in France, it must be the SCART
pin 1 you mention.

Let's say, it would be a plus if the widescreen transmission signal
could be sent. But I can still switch my tv to full widescreen if tv-out
is anamorphic.

>
> B) can you record/play anamorphic?
> Yes, no problem. Anamorphic just means you squash the image into 4:3
> when transmitting it, it is only handled by the camera and the final
> display, any transfer channel in between (and myhtTV in this case is
> just a time-delayed transfer channel) just had to pass it along the data
> unchanged. As a user-aid a 1-bit flag is included to indicate the
> anamorphic format.

great news. Even though, there are a few channels which broadcast 16:9
programmes :-\

> If you can detect the flag correctly you can even flatten the display of
> the XV window on the computerscreen.
>

Not sure I understand what you mean. But since, I haven't yet built and
played with MythTV, let's move forward .

> 4/ Last, I'm wondering if there's a difference in terms of quality
> between tv tuner cards for video grabbing, and particularly in my case
> for s-video input grabbing. The differences could be, I guess, on
> maximum resolution, visual quality, widescreen handling, ... So if you
> could share your experience, I would appreciate your feedback.
> Max resolution is fixed for any PAL or NTSC standard. You can't grab any
> more lines then are transmitted, you just have to accept TV was meant
> for a V screen. If you have satelite or cable, perhaps you can grab some
> digital channels, they are not limited that way, but MythTV just
> supports analog TV tuner cards (for now???).
>

So there are some limitations in quality due to the source itself. But,
for a same video source, are there some differences in terms of visual
quality between one tv tuner card and another ? Maybe some cards have
better decoding chips ?

> Erik
>

Thanks very much Erik.

Laurent
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev [at] snowman
> http://www.snowman.net/mailman/listinfo/mythtv-dev
>

erik_nospam.arendse at bigfoot

Jan 20, 2003, 4:46 AM

Post #4 of 27 (4719 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 12:31, Laurent Farcy wrote:
>>If you can detect the flag correctly you can even flatten the display of
>>the XV window on the computerscreen.
>>Not sure I understand what you mean. But since, I haven't yet built and
>>played with MythTV, let's move forward .

MythTV shows some screens with an menu plus integrated videoscreen
(http://mythtv.sourceforge.net/mc/playbackgrab.png). If you see them in 4:3
(on monitor or normal TV), but the program is anamorphic, then the menu
itself will be normal but the people in the picture will be long and thin.
If you put your TV in 16:9 anamorphic (or just turn down the V-scale of
your monitor until you have the same deformation) and go to the menu, the
menu will be deformed (not much of a problem as long as you can read it),
anamorphic pictures will be normal, but any normal shows will have short
fat people.

If mythTV knows which format a recording has and could control your TV, it
can turn the TV in 4:3 for all menus, and show normal pictures as 4:3,
while showing pictures from anamorphic sources squashed into 16:9.

>So there are some limitations in quality due to the source itself. But,
>for a same video source, are there some differences in terms of visual
>quality between one tv tuner card and another ? Maybe some cards have
>better decoding chips ?
Yes they do, and on the risk of being flamed: the difference on the output
is bigger than on the input.
This does not have any technological reason, it's just the way the market
and the producers work at the moment.
Meaning get your output right before spending money on the input. (As long
as you watch on your monitor it is not an issue of course).

Erik

bjm at lvcm

Jan 20, 2003, 5:08 AM

Post #5 of 27 (4719 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Laurent Farcy wrote:
.
> 3/ Not so many threads talk about widescreen tvs/programmes. Although,
> some of you guys own one. So, to make short, my question is whether
> MythTV compatible with widescreen programmes and TVs ? IMHO, 'compatible
> with widescreen programmes' would mean recordings happen in anamorphic
> aspect ratio (whenever the source is anamorphic) so that when you read
> them you can still expand it to 16:9 (whilst it's been recorded in 4:3
> anamorphic format). And 'compatible with widescreen tv' would mean you
> can generate a tv-output signal which is 4:3 anamorphic so that your tv
> can expand it to 16:9. Am I clear/right ?

Yes. The fullscreen mode is set to the dimensions of the
X desktop. If you recorded 4:3 video and displayed on a
16:9 desktop it would be stretched horizontally by default.
In fact, the default record dimensions are 480x480 to save
on resources. These become 4:3 when displayed at 800x600 for
example. It will be easy to letterbox 16:9 on a 4:3 display
or 4:3 on 16:9 as an option but, as you've noticed, there
hasn't been any call for it yet so it is not a high
priority ;-)

> 4/ Last, I'm wondering if there's a difference in terms of quality
> between tv tuner cards for video grabbing, and particularly in my case
> for s-video input grabbing. The differences could be, I guess, on
> maximum resolution, visual quality, widescreen handling, ... So if you
> could share your experience, I would appreciate your feedback.

I've played the "Video Essentials" DVD from a DVD player
into the S-video input of bttv card and recorded at 720x480.
My conclusion was that the bt chip clocks latch at the right
time and correctly assign digital values for the analog signal
that it is sampling and sends the raw video data down the bus.
There doesn't appear to be much room for improvement in the
quality of capture.

Most quality problems have to do with presentation and the
quality of the input signal. The capture card task of sampling
is really pretty simple. However, there was a card discussed
on this list that apparently has a shielding problem which
adds interference.

For broadcast TV over coaxial cable, 480x480 or ever 352x480
look nearly as good as 640x480. However, with your digital
cable, and especially channels that are true digital, you will
see better quality at higher resolutions.

-- bjm

laurent.farcy at freesbee

Jan 20, 2003, 5:09 AM

Post #6 of 27 (4709 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
> At 20-1-03 12:31, Laurent Farcy wrote:
> MythTV shows some screens with an menu plus integrated videoscreen
> (http://mythtv.sourceforge.net/mc/playbackgrab.png). If you see them in
> 4:3 (on monitor or normal TV), but the program is anamorphic, then the
> menu itself will be normal but the people in the picture will be long
> and thin.
> If you put your TV in 16:9 anamorphic (or just turn down the V-scale of
> your monitor until you have the same deformation) and go to the menu,
> the menu will be deformed (not much of a problem as long as you can read
> it), anamorphic pictures will be normal, but any normal shows will have
> short fat people.
>
> If mythTV knows which format a recording has and could control your TV,
> it can turn the TV in 4:3 for all menus, and show normal pictures as
> 4:3, while showing pictures from anamorphic sources squashed into 16:9.
>

now it's clear. Thx.

>> So there are some limitations in quality due to the source itself.
>> But, for a same video source, are there some differences in terms of
>> visual quality between one tv tuner card and another ? Maybe some
>> cards have better decoding chips ?
>
> Yes they do, and on the risk of being flamed: the difference on the
> output is bigger than on the input.
> This does not have any technological reason, it's just the way the
> market and the producers work at the moment.
> Meaning get your output right before spending money on the input. (As
> long as you watch on your monitor it is not an issue of course).

I read the Conexant 25871 chip is the better one. But video card
manufacturers don't always mention the chip they use for their product.
Any nvidia geforce-based video card with the conexant 25871 embedded you
may know ? Or any other recommendations ?

>
> Erik
>

Laurent
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev [at] snowman
> http://www.snowman.net/mailman/listinfo/mythtv-dev
>

erik_nospam.arendse at bigfoot

Jan 20, 2003, 5:25 AM

Post #7 of 27 (4694 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 13:09, Laurent Farcy wrote:
>>Meaning get your output right before spending money on the input. (As
>>long as you watch on your monitor it is not an issue of course).
>
>I read the Conexant 25871 chip is the better one. But video card
>manufacturers don't always mention the chip they use for their product.
>Any nvidia geforce-based video card with the conexant 25871 embedded you
>may know ? Or any other recommendations ?

Just one: _DO_NOT_ convert your signal to composite again, whatever the chip...
As I said in a previous post, if you live in France your probably have
SCART on your TV. That can be composite, better: Y/C or even best: RGB, so
just hope for the latter. RGB 100Hz progressive input straight from the
computer DAC with the correct levels leaves all other forms of output
behind in the dust, both on specs and on visual impact.
If you spend enough on your TV you can use this, if not go slowly down
quality-lane, never use composite (or, ...shudder...: modulated composite
over the antenna wire) as your first option.

I wrote a small essay about this stuff once on this list, just read this:
http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=47237;search_string=scart;guest=57834&t=search_engine#47237
(in case the link breaks in the maillist, use the myth-dev list
searchengine to search for 'scart')

A longer explanation about this can be found on
http://www.projectorcentral.com/component.htm,
it discusses connecting DVD-players to projectors, but the principles stay
exactly the same.

Erik

bjm at lvcm

Jan 20, 2003, 6:01 AM

Post #8 of 27 (4713 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
...
> If mythTV knows which format a recording has and could control your TV,
> it can turn the TV in 4:3 for all menus, and show normal pictures as
> 4:3, while showing pictures from anamorphic sources squashed into 16:9.

Do not attempt to adjust your set. We control the vertical.
We control the horizontal. The best approach would be to
leave the TV, and thus the X screen, at 16:9 then set the
dimension of the Xv output to the desired aspect ratio.

-- bjm

erik_nospam.arendse at bigfoot

Jan 20, 2003, 6:19 AM

Post #9 of 27 (4709 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 14:01, you wrote:
>>If mythTV knows which format a recording has and could control your TV,
>>it can turn the TV in 4:3 for all menus, and show normal pictures as 4:3,
>>while showing pictures from anamorphic sources squashed into 16:9.
>Do not attempt to adjust your set. We control the vertical.
>We control the horizontal. The best approach would be to
>leave the TV, and thus the X screen, at 16:9 then set the
>dimension of the Xv output to the desired aspect ratio.

Nope.

That's just when you have a _real_ physical anamorphic 16:9 display. At
home I have a TV (CRT tube) which can switch over to 16:9. It does that by
deflecting the rays less in the vertical direction, so I still have the
same amount of lines.
If I leave that TV in 16:9 mode for a normal picture (myth-menu or
TV-show), and mythtv would correct the 4:3 images to fit inside the 16:9
box, I would end up with a small box in the middle of BigBlackBorders(tm).
Same story for projectors with real anamorphic support.

Erik

laurent.farcy at freesbee

Jan 20, 2003, 6:44 AM

Post #10 of 27 (4725 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Bruce Markey wrote:
> Laurent Farcy wrote:
>> 4/ Last, I'm wondering if there's a difference in terms of quality
>> between tv tuner cards for video grabbing, and particularly in my case
>> for s-video input grabbing. The differences could be, I guess, on
>> maximum resolution, visual quality, widescreen handling, ... So if you
>> could share your experience, I would appreciate your feedback.
>
>
> I've played the "Video Essentials" DVD from a DVD player
> into the S-video input of bttv card and recorded at 720x480.
> My conclusion was that the bt chip clocks latch at the right
> time and correctly assign digital values for the analog signal
> that it is sampling and sends the raw video data down the bus.
> There doesn't appear to be much room for improvement in the
> quality of capture.
>

It sounds great because it means even cheap tv tuner cards can fit.

>
> For broadcast TV over coaxial cable, 480x480 or ever 352x480
> look nearly as good as 640x480. However, with your digital
> cable, and especially channels that are true digital, you will
> see better quality at higher resolutions.
>

Unfortunately, my MythTV box is not ready yet. But, as soon as it is, I
will make some live test to experience the difference.

> -- bjm
>

Laurent

laurent.farcy at freesbee

Jan 20, 2003, 6:44 AM

Post #11 of 27 (4714 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
> At 20-1-03 13:09, Laurent Farcy wrote:
>
>>> Meaning get your output right before spending money on the input. (As
>>> long as you watch on your monitor it is not an issue of course).
>>
>>
>> I read the Conexant 25871 chip is the better one. But video card
>> manufacturers don't always mention the chip they use for their
>> product. Any nvidia geforce-based video card with the conexant 25871
>> embedded you may know ? Or any other recommendations ?
>
>
> Just one: _DO_NOT_ convert your signal to composite again, whatever the
> chip...
> As I said in a previous post, if you live in France your probably have
> SCART on your TV. That can be composite, better: Y/C or even best: RGB,
> so just hope for the latter. RGB 100Hz progressive input straight from
> the computer DAC with the correct levels leaves all other forms of
> output behind in the dust, both on specs and on visual impact.
> If you spend enough on your TV you can use this, if not go slowly down
> quality-lane, never use composite (or, ...shudder...: modulated
> composite over the antenna wire) as your first option.
>

I cannot use RGB output because my dvd player is already plugged in my
only rgb-compatible scart on my tv. Except if I use a multiple SCART
adapter but I don't really want to.

I thought using s-video output rather. You can find many geforce-based
video card with a s-video tv output at reasonable prices. But,
apparently, the quality of the tv output depends on the chip used to
encode the signal (vga 2 ntsc/pal converter). And the conexant chip I
mentioned is told to be the best.

I just wanted to double-check with you guys and had some recommendations
on products. Thanks for your advice Erik.

Laurent

erik_nospam.arendse at bigfoot

Jan 20, 2003, 6:59 AM

Post #12 of 27 (4709 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 14:44, you wrote:
> I cannot use RGB output because my dvd player is already plugged in my
>only rgb-compatible scart on my tv. Except if I use a multiple SCART
>adapter but I don't really want to.

Just create a auto-switch adapter. You can switch to the DVD player
whenever you detect an output signal, otherwise connect the PVR. That's
what I'm going to do, same situation here. I only turn on the DVD player
when I use it, so it will default to mythTV. Final target is removing the
antenna input from the TV altogether, and use it as a display for the PVR.

I don't think you can buy a good quality switch though, I am going to use a
few miniature relais (best quality for low price), so if you have
solder-iron-fear or a tight budget this one is not for you :-)

For an idea of commercial automatic products (no idea about quality):
http://www.threedoubleyou.com/quattroscart.htm

Erik

bjm at lvcm

Jan 20, 2003, 7:04 AM

Post #13 of 27 (4733 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
> At 20-1-03 14:01, you wrote:
>
>>> If mythTV knows which format a recording has and could control your
>>> TV, it can turn the TV in 4:3 for all menus, and show normal pictures
>>> as 4:3, while showing pictures from anamorphic sources squashed into
>>> 16:9.
>>
>> Do not attempt to adjust your set. We control the vertical.
>> We control the horizontal. The best approach would be to
>> leave the TV, and thus the X screen, at 16:9 then set the
>> dimension of the Xv output to the desired aspect ratio.
>
>
> Nope.
>
> That's just when you have a _real_ physical anamorphic 16:9 display.

I thought Laurent was referring to a physical 16:9 display.
I didn't realize you had something different...

> ...At
> home I have a TV (CRT tube) which can switch over to 16:9. It does that
> by deflecting the rays less in the vertical direction, so I still have
> the same amount of lines.

So it is physically 4:3? In the US, all I've ever seen are
16:9 for high definition. I'd prefer a 4:3 screen that could
compress the raster lines for HDTV. What brand/model do you
have? I assume it isn't compatible with US TV but I'm curious
to see any sets that work this way.

-- bjm

laurent.farcy at freesbee

Jan 20, 2003, 7:25 AM

Post #14 of 27 (4735 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Bruce Markey wrote:
> Erik Arendse wrote:
>
>> At 20-1-03 14:01, you wrote:
>>
>>>> If mythTV knows which format a recording has and could control your
>>>> TV, it can turn the TV in 4:3 for all menus, and show normal
>>>> pictures as 4:3, while showing pictures from anamorphic sources
>>>> squashed into 16:9.
>>>
>>>
>>> Do not attempt to adjust your set. We control the vertical.
>>> We control the horizontal. The best approach would be to
>>> leave the TV, and thus the X screen, at 16:9 then set the
>>> dimension of the Xv output to the desired aspect ratio.
>>
>>
>>
>> Nope.
>>
>> That's just when you have a _real_ physical anamorphic 16:9 display.
>
>
> I thought Laurent was referring to a physical 16:9 display.
> I didn't realize you had something different...
>

I confirm : I've got a physical 16:9 display (Sony KV32FX60B, not HDTV).
So, what's best ? Adjust the set to stretch an 4:3 anamorphic image or
adjust the Xv output ? From a strict user standpoint, it seems easier to
adjust the tv set since it is pressing one button om my remote control.
It is not 'reconfiguration' when switching from a 4:3 to a 16:9 channel
(most of them are still in 4:3).

Laurent

bjm at lvcm

Jan 21, 2003, 2:08 AM

Post #15 of 27 (4692 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

bjm at lvcm

Jan 21, 2003, 2:40 AM

Post #16 of 27 (4714 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Laurent Farcy wrote:
...
> I confirm : I've got a physical 16:9 display (Sony KV32FX60B, not HDTV).
> So, what's best ? Adjust the set to stretch an 4:3 anamorphic image or
> adjust the Xv output ? From a strict user standpoint, it seems easier to
> adjust the tv set since it is pressing one button om my remote control.
> It is not 'reconfiguration' when switching from a 4:3 to a 16:9 channel
> (most of them are still in 4:3).

One thing to consider is that MythTV is running over X so
X must always work. If, for instance, a change were made
from an interlaced mode to progressive, The X screen would
lose synch. However, if it is the same raster timing but
stretched on the screen then this isn't an issue and
switching the TV will work.

The reason I'd suggest 16:9 is based on the assumption that
you can use a higher horizontal resolution with square pixels.
For me, I'd prefer keeping the maximum X screen space possible
filling the physical dimensions of the screen then adjusting
the width or height of the Xv display area to correct the
aspect ratio.

-- bjm

erik_nospam.arendse at bigfoot

Jan 22, 2003, 1:32 AM

Post #17 of 27 (4700 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 15:04, Bruce Markey wrote:
>If mythTV knows which format a recording has and could control your TV, it
>can turn the TV in 4:3 for all menus, and show normal pictures as 4:3,
>while showing pictures from anamorphic sources squashed into 16:9.
>>>
>>>Do not attempt to adjust your set. We control the vertical.
>>>We control the horizontal. The best approach would be to
>>>leave the TV, and thus the X screen, at 16:9 then set the
>>>dimension of the Xv output to the desired aspect ratio.
>>
>>Nope.
>>That's just when you have a _real_ physical anamorphic 16:9 display.
>
>I thought Laurent was referring to a physical 16:9 display.
>I didn't realize you had something different...

>>home I have a TV (CRT tube) which can switch over to 16:9. It does that
>>by deflecting the rays less in the vertical direction, so I still have
>>the same amount of lines.
>
>So it is physically 4:3? In the US, all I've ever seen are
>16:9 for high definition. I'd prefer a 4:3 screen that could
>compress the raster lines for HDTV. What brand/model do you
>have? I assume it isn't compatible with US TV but I'm curious
>to see any sets that work this way.

Short story:

Philips, don't know the model but nearly every non-portable newer 4:3 can,
most upper models are compatible with NTSC but not HDTV.

Long story:

At the moment half of the TV's for sale over here (Netherlands) are 16:9
displays, half are 4:3.
All use the PAL 625 lines, 25Hz interlaced source. Some have a frambuffer
and interlacer on board, and end up with 50Hz non-interfaced, 100Hz
interlaced, or 100Hz non-interlaced.
Some have interpolation (most notably plasma and TFT screens) and scale up
from 625 to whatever.
We have a special broadcast norm being introduced (since 1995) which uses
PAL to transmit a letterboxed image, but in the black bars below/above the
picture extra lines are hidden (in such a way to be below the blacklevel on
a normal TV). Using a framebuffer a PAL-Plus TV can use these to
reconstruct a 16:9 image with a higher resolution compared to the
letterboxed one visible on the 4:3 TV.

HDTV is not really available here, there were some experiments but the
equipment was very hard to get and the norm used (D2MAC) was more-or-less
discarded . And even I believe some of the available equipment was just a
converter to degrade the digital HDTV to an analog PAL to display on a
normal 4:3 set.

Back to the question:
My TV (Philips, branded Aristona, Philips brand is originally Dutch (but
now just another global company) available everywhere - but mostly Europe
and Asia - under several names, most models country specific) can lower the
vertical deflection so all horizontal lines squeeze in the leterboxed
needed to show a 16:9 image with the width of the physical 4:3 tube (Phew,
mouthfull...). This is only useful for DVD (or PC's) as they are the only
16:9 sources here, packing a 16:9 image anamorphic into a transport
developed for 4:3. A theroetical "PAL-Plus to anamorphic PAL" converter
could be used as well, but I have never heard such a beast existing.
By the way: the set does support NTSC the manual says, so if you send some
money my way I could put it in a box and ship it your way :-)

The benefit of all this is based on the fact that that most of the
tranmissions here are 4:3, slowly moving to 16:9. Most commercial channels
here will never transmit 16:9 yet out of fear some viewers will run away
when they see a set of black bars.

If you watch 16:9 on a physical 4:3 you end up with a letterboxed image.
The other way around you end up with a vertical "leterboxed" image. As most
material is 4:3 I have to watch the smallest hours of black bars this way.
Other issue is that although on paper the 16:9 tubes are bigger, that is
only because the diagonal is cited. The final size of a 16:9 picture is
comparable within the same price-range for both 16:9 and 4:3, but the size
of a 4:3 image will be a lot bigger on the 4:3.

Finally a weird tale (to me at least): As we sell so many 16:9 tubes, and
as there are so few 16:9 transmissions, everybody puts their TV in some
sort of "stretched" mode which deforms the 4:3 picture to 16:9...
And everybody thinks this is neat, except for a handful of people who use
their eyes, including yours truly.

Erik

erik_nospam.arendse at bigfoot

Jan 22, 2003, 1:38 AM

Post #18 of 27 (4725 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 20-1-03 15:25, Laurent Farcy wrote:
> I confirm : I've got a physical 16:9 display (Sony KV32FX60B, not HDTV).
So, what's best ? Adjust the set
> to stretch an 4:3 anamorphic image or adjust the Xv output ? From a
strict user standpoint, it seems
>easier to adjust the tv set since it is pressing one button om my remote
control. It is not 'reconfiguration'
>when switching from a 4:3 to a 16:9 channel (most of them are still in 4:3).

- what do you mean by adjusting XV output?
- do you want to see 4:3 material stretched to 16:9?
- do you want to see a 4:3 menu streched to 16:9?
- do you have anamorphic 16:9 sources you want to record with mythtv?

Erik

laurent.farcy at freesbee

Jan 22, 2003, 4:00 AM

Post #19 of 27 (4729 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
> At 20-1-03 15:25, Laurent Farcy wrote:
> > I confirm : I've got a physical 16:9 display (Sony KV32FX60B, not
> HDTV). So, what's best ? Adjust the set
> > to stretch an 4:3 anamorphic image or adjust the Xv output ? From a
> strict user standpoint, it seems
> >easier to adjust the tv set since it is pressing one button om my
> remote control. It is not 'reconfiguration'
> >when switching from a 4:3 to a 16:9 channel (most of them are still in
> 4:3).
>
> - what do you mean by adjusting XV output?

I was just referring to another reply I had from Bruce Markey.

>> Do not attempt to adjust your set. We control the vertical.
>> We control the horizontal. The best approach would be to
>> leave the TV, and thus the X screen, at 16:9 then set the
>> dimension of the Xv output to the desired aspect ratio.

So my question is : what is the best solution considering image
definition/quality and ease of use. I don't want to reconfigure Xv for
each different material. Let's say, in 2 minutes, I can switch from 4:3
to 16:9 and back to 4:3 sources just because I'm zapping.

> - do you want to see 4:3 material stretched to 16:9?

no, I want to respect the original aspect ratio. I don't care about
stretching an original 4:3 material.

> - do you want to see a 4:3 menu streched to 16:9?

if this is not avoidable for watching a 'true' 16:9 material, it is ok.
I think it is already what happens with my cable receiver. Although it
has an item in the setup to declare a widescreen tv, menus are only
designed for a 4:3 image.

> - do you have anamorphic 16:9 sources you want to record with mythtv?

yes. Maybe dvd, but mostly movies broadcasted on (rare) 16:9 movie channels.

>
> Erik
>

Laurent

erik_nospam.arendse at bigfoot

Jan 22, 2003, 4:13 AM

Post #20 of 27 (4736 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 22-1-03 12:00, Laurent Farcy wrote:
> So my question is : what is the best solution considering image
definition/quality and ease of use. I don't
> want to reconfigure Xv for each different material. Let's say, in 2
minutes, I can switch from 4:3 to 16:9
> and back to 4:3 sources just because I'm zapping.

OK, lets see:

>>- do you want to see 4:3 material stretched to 16:9?
>no, I want to respect the original aspect ratio. I don't care about
>stretching an original 4:3 material.

>>- do you want to see a 4:3 menu streched to 16:9?
>if this is not avoidable for watching a 'true' 16:9 material, it is ok. I
>think it is already what happens with my cable receiver. Although it has
>an item in the setup to declare a widescreen tv, menus are only designed
>for a 4:3 image.

>>- do you have anamorphic 16:9 sources you want to record with mythtv?
>yes. Maybe dvd, but mostly movies broadcasted on (rare) 16:9 movie channels.
Is a 16:9 movie channel anamorphic, letterboxed PAL or PAL-Plus? Just for
curiosity: could you give me a name or link?

Seems to me you can just record whatever you want using an un-modified
MythTV, and show it with your TV switched manually to 16:9 or 4:3.

Changing resolutions in MythTV for different sources is no issue as you
supposedly just grab the maximum attainable with your hardware, up to the
limits of PAL. Quality will not be compromised with either 16:9 or 4:3 sources.

Future possible support of digital input is a different matter though.

If you want menu's scaled is up to you, they are certainly usable if
stretched (as your cable receiver).

The only possible improvement could be letting MythTV control your TV ratio
over a scart connection, but then you should hack around in mythTV and
probably run a wire from some free LPT line to your scart.

Erik

laurent.farcy at freesbee

Jan 22, 2003, 4:48 AM

Post #21 of 27 (4720 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Erik Arendse wrote:
>
> Is a 16:9 movie channel anamorphic, letterboxed PAL or PAL-Plus? Just
> for curiosity: could you give me a name or link?
>

It is some 16:9 movie channels anamorphic like Digital Canal+. See the
description (in french) of the 16/9 service here :

http://www.canalplus.fr/espace_client/canalplusetvous/html/plus_du_numeriqueEC.html

> Seems to me you can just record whatever you want using an un-modified
> MythTV, and show it with your TV switched manually to 16:9 or 4:3.
>

Exactly.

>
> Erik
>

Laurent

bjm at lvcm

Jan 22, 2003, 5:29 AM

Post #22 of 27 (4726 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

There is a lot of interesting information here. Thanks for
sending this.

Erik Arendse wrote:
...
> We have a special broadcast norm being introduced (since 1995) which
> uses PAL to transmit a letterboxed image, but in the black bars
> below/above the picture extra lines are hidden (in such a way to be
> below the blacklevel on a normal TV). Using a framebuffer a PAL-Plus TV
> can use these to reconstruct a 16:9 image with a higher resolution
> compared to the letterboxed one visible on the 4:3 TV.

If I understand this correctly, the letterboxed lines in
the 4:3 image are common to both then every third or fourth
PAL-Plus line is added. Are there any capture cards capable
of doing this reconstruction? Or, at least assign digital
values to the blacker-than-black information so that the
reconstruction could be done in software?

> Back to the question:
> My TV (Philips, branded Aristona, Philips brand is originally Dutch (but
> now just another global company) available everywhere - but mostly
> Europe and Asia - under several names, most models country specific) can
> lower the vertical deflection so all horizontal lines squeeze in the
> leterboxed needed to show a 16:9 image with the width of the physical
> 4:3 tube (Phew, mouthfull...).

Got it. The one thing I want to understand here is if the
only change is that the scan lines are closer together. If
the synch timings change, an X display may not survive the
transition. If it continues normal PAL and merely squashes
down then this would work well for myth. Since the default
is to stretch the image the the X dimensions, and this
squashes the X desktop to 16:9 a 16:9 image should look
normal (with the advantage of denser lines than 4:3 mode).

> This is only useful for DVD (or PC's) as
> they are the only 16:9 sources here, packing a 16:9 image anamorphic
> into a transport developed for 4:3. A theroetical "PAL-Plus to
> anamorphic PAL" converter could be used as well, but I have never heard
> such a beast existing.
> By the way: the set does support NTSC the manual says, so if you send
> some money my way I could put it in a box and ship it your way :-)

I wouldn't feel comfortable sending cash but I would be
happy to offer you ownership of a famous bridge in New York
City in exchange for your TV ;-).

> The benefit of all this is based on the fact that that most of the
> tranmissions here are 4:3, slowly moving to 16:9. Most commercial
> channels here will never transmit 16:9 yet out of fear some viewers will
> run away when they see a set of black bars.

Interesting, here some shows and commercials deliberately
chop a little off the top and bottom to give the illusion
that it is some special widescreen broadcast ;-).

> If you watch 16:9 on a physical 4:3 you end up with a letterboxed image.
> The other way around you end up with a vertical "leterboxed" image. As
> most material is 4:3 I have to watch the smallest hours of black bars
> this way.

Understood.

> Other issue is that although on paper the 16:9 tubes are bigger, that is
> only because the diagonal is cited. The final size of a 16:9 picture is
> comparable within the same price-range for both 16:9 and 4:3, but the
> size of a 4:3 image will be a lot bigger on the 4:3.

I have a 70" Mitsubishi so the width is 56" by 42" high.
A 56" wide 16:9 screen uses the same guns, mirrors, etc.,
except the screen is chopped down to 31.5" high. Both show
16:9 at 56"x31.5" but the 4:3 image on the widescreen is
only about 42"x31.5" rather than 56"x42". Since the width
is most important in determines the size of the piece of
furniture and the internal components needed, it seems to
me that we're just being cheated ;-).

> Finally a weird tale (to me at least): As we sell so many 16:9 tubes,
> and as there are so few 16:9 transmissions, everybody puts their TV in
> some sort of "stretched" mode which deforms the 4:3 picture to 16:9...
> And everybody thinks this is neat, except for a handful of people who
> use their eyes, including yours truly.

I couldn't agree more. I think the TV sellers benefit from
the "wow" factor. The widescreen shape makes the sets look
like the latest 'state of the art' thing. With a 4:3 screen,
a widescreen image letterboxed looks smaller (less impressive).
On a widescreen set, the 4:3 is smaller than the more
impressive widescreen image. I believe these two reasons
are why the showrooms are filled with widescreen models.

So, they take last year's model, chop down the height, charge
twice as much money, then people take them home and watch
distorted images most of the time. It boggles the mind =).

-- bjm

bjm at lvcm

Jan 22, 2003, 6:09 AM

Post #23 of 27 (4728 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

Laurent Farcy wrote:
...
> So my question is : what is the best solution considering image
> definition/quality and ease of use. I don't want to reconfigure Xv for
> each different material. Let's say, in 2 minutes, I can switch from 4:3
> to 16:9 and back to 4:3 sources just because I'm zapping.

Sorry, this can be difficult to keep track all the details.
I want to clarify that there is nothing you need to do to
reconfigure Xv. What I'm suggesting is that you choose the
highest resolution possible for your X desktop that fills
the physical screen and stay in that mode. The software could
set the dimension within the X screen to force the aspect
ration to be 4:3 or 16:9. There could be a single button
on the myth remote control to switch between 4:3 and 16:9.
Since you would be changing channels (or picking recordings)
with the myth remote you wouldn't need to pick up the TV
remote to change modes.

Two concerns I would have with switching the TV:

1) If the synch timings change the X desktop could not
display in both modes. You would have to stick to one
or the other.

2) One mode would allow for a higher X resolution than the
other. If it was my choice, I would prefer keeping as many
pixels on the screen as possible at all times and shaping
the image within the higher resolution mode.

Now, Erik's TV is different than yours. In his case the
best thing would be to use the highest 4:3 X resolution
then use the deflection mode for 16:9 images.

-- bjm

erik_nospam.arendse at bigfoot

Jan 22, 2003, 6:31 AM

Post #24 of 27 (4721 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 22-1-03 14:09, Bruce Markey wrote:
>Laurent Farcy wrote:
>...
>>So my question is : what is the best solution considering image
>>definition/quality and ease of use. I don't want to reconfigure Xv for
>>each different material. Let's say, in 2 minutes, I can switch from 4:3
>>to 16:9 and back to 4:3 sources just because I'm zapping.
>...
>Two concerns I would have with switching the TV:
>
>1) If the synch timings change the X desktop could not
>display in both modes. You would have to stick to one
>or the other.

If Laurent switches his TV _nothing_ changes in the incoming signal. It is
just an option of displaying the inncomping pal in the middle 4:3 square or
in the full 16:9 tube.

>2) One mode would allow for a higher X resolution than the
>other. If it was my choice, I would prefer keeping as many
>pixels on the screen as possible at all times and shaping
>the image within the higher resolution mode.

No use. The grabbed source is always maximum for the incoming PAL signal
(about 640x480). Outgoing signal from mythtv to the TV is always PAL, which
has about 640x480 maximum usable _visible_ resolution.
This cannot be increased (even if it would make sense for the bigger tube)
because the transport (PAL) limits the horizontal resolution with a analog
filter, and the vertical resolution with the PAL standard itself.

>Now, Erik's TV is different than yours. In his case the
>best thing would be to use the highest 4:3 X resolution
>then use the deflection mode for 16:9 images.
I agree on that one.

But Laurent can only transport PAL to his TV either, and the only
alternative he has is letting al MythTV output display in 16:9, and if it
is a 4:3 source "shaping the image within the higher resolution mode" as
you describe it. If you take that route however he looses information,
because the PAL circuitry does not allow a higher horizontal resolution and
you end up with squeezing the original full PAL horizontal linelength into
the middle part of your generated PAL line.

To complicate matters: your reasoning is valid for a 16:9 projector (Sony
and Panasic both have one) _if_you_use_vga_or_rgb_inputs_ and are not
limited in the horizontal resolution you can transfer. If you just use a
videoconnector with PAL input the previous applies.

Erik

erik_nospam.arendse at bigfoot

Jan 22, 2003, 6:33 AM

Post #25 of 27 (4745 views)
Permalink

Re: s-video input / widescreen tv ? [In reply to]

At 22-1-03 13:29, Bruce Markey wrote:
>If I understand this correctly, the letterboxed lines in
>the 4:3 image are common to both then every third or fourth
>PAL-Plus line is added. Are there any capture cards capable
>of doing this reconstruction? Or, at least assign digital
>values to the blacker-than-black information so that the
>reconstruction could be done in software?
I could never find any card that could do it. But I want one. Not sure if
software is enough, don't think so as it should behave default as a normal
non-PAL-Plus TV. But perhaps the chips used have lots of twiddle-registers...

>The one thing I want to understand here is if the
>only change is that the scan lines are closer together. If
>the synch timings change, an X display may not survive the
>transition. If it continues normal PAL and merely squashes
>down then this would work well for myth.
It just squashes down, input stays 100% unchanged.

>Interesting, here some shows and commercials deliberately
>chop a little off the top and bottom to give the illusion
>that it is some special widescreen broadcast ;-).
Same here. Probably the owners of the channels never watch the commercials
they get paid to transmit, or read in some old report that some people
don't like letterboxing. The guys making those commercials just read newer
reports :-)

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