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Adventures in HDTV - Notes from the trenches

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matt at mossholder

Dec 18, 2005, 8:17 PM

Post #1 of 15 (3320 views)
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Adventures in HDTV - Notes from the trenches

Hi everyone,
Been working for a few weeks trying to get a functional front end.
The good news is no more questions. :) However, I picked up a number of
tid-bits along the way, and figured it would be a good thing to
summarize them for the list, to help the next person.

HDTVs:
=====

1) Try and ensure that the TV you intend to purchase does not -require-
HDCP enabled input sources for HDMI or DVI connections before you make a
purchase. This has a number of bad side effects, listed below.

2) A display capable of 720p is preferable to one capable of 1080i,
under many circumstances. 720p has less flicker, and presents less
problems from a display driver standpoint. One that supports both (or
1080p) is even better.

Display Cards:
=========

1) nVIDIA (generally preferred) - There are a number of issues that you
may run into. Careful selection of a driver version is required to
ensure proper functionality.

*) If you require interlaced display modes, choose version 6629, if
you are using progressive, you can go with the latest version.
*) If your display requires HDCP enabled sources and you want to use
HDMI or DVI, you will need to use a 6000 series or 7000 series adapter,
since previous versions of nVIDIA cards do not support HDCP.
*) if you are using an AudioAuthority 9A60 VGA-> Component adapter,
be aware that somewhere above version 6629 the nVIDIA drivers began
experiencing an issue when using 1080i mode, where the display would be
shifted such that the left and right edges are in the middle of the
screen.
*) There is an outstanding bug in versions higher than 6629 when
utilizing a DVI connection which prevents the use of xv VBlank syncing.
I've seen it mentioned that this is just with interlaced modes, but in
my experience, it seems to crash right away whenever the DVI port is
being used.

2) ATI (getting better, but not quite there yet for HD) - ATI seems to
deliver a better picture, when working, however there are issue which
seem to preclude using these cards for 1080i.

*) Xv does not work properly with large displays. The symptoms of
this are that Myth thinks everything is working fine, but a black screen
is presented when video should be on screen. X displays non-video
content correctly (X Desktop, MythTV GUI, etc). Some people appear to
have managed to get 720 working correctly, but 1080i is too large.
*) While ATI supports HDCP, it is only enabled when the fglrx X11
driver is loaded. It's another gotcha for those of us with HDTV monitors
which require HDCP on the DVI or HDMI port. If you are in this
situation, you are going to be flying blind until X comes up. Really
only workable if you are running a diskless system, where all the
configuration can happen on another system, or if you do the initial
configuration on a normal monitor.

adeffs at gmail

Dec 18, 2005, 8:52 PM

Post #2 of 15 (3264 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Sunday 18 December 2005 23:17, Matt Mossholder wrote:
> 1) Try and ensure that the TV you intend to purchase does not -require-
> HDCP enabled input sources for HDMI or DVI connections before you make a
> purchase. This has a number of bad side effects, listed below.

or get a 6000 or 7000 series card as you mention below.

> 2) A display capable of 720p is preferable to one capable of 1080i,
> under many circumstances. 720p has less flicker, and presents less
> problems from a display driver standpoint. One that supports both (or
> 1080p) is even better.

no HDTV currently accepts 1080p input.
1080i should be fine, I can't imagine any noticable flicker in a proper set up
on a good 1080i tv. Hell, even my cheap Sanyo displays 1080i with no
noticable flicker.
If your TV is not actually a native 1080i tv though, then there might be some
issue with 1080i input.

> *) If you require interlaced display modes, choose version 6629, if
> you are using progressive, you can go with the latest version.

Interesting. So interlace does work on the older drivers! I wonder what the
downside to running 6629 over 7676 is. Time to get a GeForce card with a GPU
that supports interlaced output....

> *) if you are using an AudioAuthority 9A60 VGA-> Component adapter,
> be aware that somewhere above version 6629 the nVIDIA drivers began
> experiencing an issue when using 1080i mode, where the display would be
> shifted such that the left and right edges are in the middle of the
> screen.

If your using an NVidia card to output to a 1080i tv you should be using the
DVI connector, if not, just get one with built in component hdtv output and
sell the AudioAuthority box.

> *) There is an outstanding bug in versions higher than 6629 when
> utilizing a DVI connection which prevents the use of xv VBlank syncing.
> I've seen it mentioned that this is just with interlaced modes, but in
> my experience, it seems to crash right away whenever the DVI port is
> being used.

I don't understand this issue? I'm using 7676 with DVI output and it doesn't
crash.

--
Steve
_______________________________________________
mythtv-users mailing list
mythtv-users[at]mythtv.org
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

matt at mossholder

Dec 18, 2005, 10:03 PM

Post #3 of 15 (3272 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Sun, 2005-12-18 at 23:52 -0500, Steve Adeff wrote:

> > 2) A display capable of 720p is preferable to one capable of 1080i,
> > under many circumstances. 720p has less flicker, and presents less
> > problems from a display driver standpoint. One that supports both (or
> > 1080p) is even better.
>
> no HDTV currently accepts 1080p input.
> 1080i should be fine, I can't imagine any noticable flicker in a proper set up
> on a good 1080i tv. Hell, even my cheap Sanyo displays 1080i with no
> noticable flicker.
> If your TV is not actually a native 1080i tv though, then there might be some
> issue with 1080i input.
>
>

I'm not seeing flicker in video content, but definitely see it in
the GUI. The higher refresh rate of 720p also does wonders for sports
programs. There are actually quite a few 1080p devices out now. The new
Sony line, for example. Not sure how you get the signal there, but they
have been advertising it far and wide. The display that I almost bought
also supported 1080p.

> > *) If you require interlaced display modes, choose version 6629, if
> > you are using progressive, you can go with the latest version.
>
> Interesting. So interlace does work on the older drivers! I wonder what the
> downside to running 6629 over 7676 is. Time to get a GeForce card with a GPU
> that supports interlaced output....

The big downside for me is that they only support the 6600 and 6800
cards at 6629. I have a 6200.

>
> > *) if you are using an AudioAuthority 9A60 VGA-> Component adapter,
> > be aware that somewhere above version 6629 the nVIDIA drivers began
> > experiencing an issue when using 1080i mode, where the display would be
> > shifted such that the left and right edges are in the middle of the
> > screen.
>
> If your using an NVidia card to output to a 1080i tv you should be using the
> DVI connector, if not, just get one with built in component hdtv output and
> sell the AudioAuthority box.

The problem below is why using the DVI port is suboptimal... it
isn't too back on SD content, but HD experiences quite a bit of tearing
w/o VBlank support.
Here's a link to a thread that discusses the split screen bug:

http://www.nvnews.net/vbulletin/showthread.php?t=49315

>
> > *) There is an outstanding bug in versions higher than 6629 when
> > utilizing a DVI connection which prevents the use of xv VBlank syncing.
> > I've seen it mentioned that this is just with interlaced modes, but in
> > my experience, it seems to crash right away whenever the DVI port is
> > being used.
>
> I don't understand this issue? I'm using 7676 with DVI output and it doesn't
> crash.

Here are a few links to other people experiencing the VBlank
problem. Basically, if I have VBlank enabled, and play back video
content with Xv, the system hangs. On further inspection it isn't
limited to DVI...

http://www.nvnews.net/vbulletin/showthread.php?t=56384

ylee at pobox

Dec 18, 2005, 11:26 PM

Post #4 of 15 (3272 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

Steve Adeff <adeffs[at]gmail.com> says:
> no HDTV currently accepts 1080p input.

Not many do, but there are some and more such models are coming out
each week; the Magnolia Audio/Video I visited last week was
highlighting their selection of them. Now, there are a few caveats:

* No readily-available source of 1080p content other than computers
(including MythTV, natch). Not cable, not over-the-air broadcasts,
not videogames. It's likely HD-DVD and Blu-Ray (including the
PlayStation 3) will carry 1080p content, though.
* TVs that take 1080p input will sometimes restrict them to only a
given input port while others only do 1080i.
* Some models that claim to do true 1080p, like a certain Sceptre 37",
will internally convert to 1080i then convert back to 1080p, or pull
some other tricks. Others, like a Westinghouse 37", is said to be
true 1080p all the way.

--
Yeechang Lee <ylee[at]pobox.com> | +1 650 776 7763 | San Francisco CA US

jarod at wilsonet

Dec 19, 2005, 12:28 AM

Post #5 of 15 (3267 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Sunday 18 December 2005 23:26, Yeechang Lee wrote:
> Steve Adeff <adeffs[at]gmail.com> says:
> > no HDTV currently accepts 1080p input.

Somebody beat me to the "BS!" call... ;)

> Not many do, but there are some and more such models are coming out
> each week; the Magnolia Audio/Video I visited last week was
> highlighting their selection of them. Now, there are a few caveats:
>
> * No readily-available source of 1080p content other than computers
> (including MythTV, natch). Not cable, not over-the-air broadcasts,
> not videogames. It's likely HD-DVD and Blu-Ray (including the
> PlayStation 3) will carry 1080p content, though.
> * TVs that take 1080p input will sometimes restrict them to only a
> given input port while others only do 1080i.
> * Some models that claim to do true 1080p, like a certain Sceptre 37",
> will internally convert to 1080i then convert back to 1080p, or pull
> some other tricks. Others, like a Westinghouse 37", is said to be
> true 1080p all the way.

I have said Westinghouse 37" TV, and it most definitely does accept and
display a GORGEOUS 1080p signal (from a GeForce 6200's DVI port).

--
Jarod Wilson
jarod[at]wilsonet.com

jarod at wilsonet

Dec 19, 2005, 12:36 AM

Post #6 of 15 (3264 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Sunday 18 December 2005 22:03, Matt Mossholder wrote:
> > 1080i should be fine, I can't imagine any noticable flicker in a proper
> > set up on a good 1080i tv. Hell, even my cheap Sanyo displays 1080i with
> > no noticable flicker.
> > If your TV is not actually a native 1080i tv though, then there might be
> > some issue with 1080i input.
>
> I'm not seeing flicker in video content, but definitely see it in
> the GUI.

I've got both a 1080i set and a 1080p set. 1080i is utterly unusable as a
display mode for the GUI, unless you like headaches. For my 1080i set, I use
a 540p mode for the GUI and SDTV, then xrandr to 1080i for HDTV content. The
1080p set stays at 1080p all the time (and is greatly preferred for viewing,
despite being 10" smaller :).

--
Jarod Wilson
jarod[at]wilsonet.com

gtgj at pacbell

Dec 19, 2005, 1:31 AM

Post #7 of 15 (3272 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

>>>>> Matt Mossholder writes:

m> 1) Try and ensure that the TV you intend to purchase does not -require-
m> HDCP enabled input sources for HDMI or DVI connections before you make a
m> purchase. This has a number of bad side effects, listed below.

Do you know which displays have this requirement? (It seems
like a poor decision to intentionally not provide backward
compatibility.)
--
Gregorio Gervasio, Jr.
_______________________________________________
mythtv-users mailing list
mythtv-users[at]mythtv.org
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

doug at ties

Dec 19, 2005, 4:53 AM

Post #8 of 15 (3263 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

Matt Mossholder wrote:
> Here are a few links to other people experiencing the VBlank
> problem. Basically, if I have VBlank enabled, and play back video
> content with Xv, the system hangs. On further inspection it isn't
> limited to DVI...
>
> http://www.nvnews.net/vbulletin/showthread.php?t=56384
> <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank>

If I'm understanding correctly, if (in nvidia-settings) "X Server XVideo
Settings -> Video Texture Adaptor -> Sync to VBlank" is checked, it
hangs? Then don't do that! Instead, to avoid tearing, uncheck that
setting, and make sure MythTV is using OpenGL vsync. This is the *only*
way to get tearing-free, stutter-free playback out of MythTV, because
it's one of only two video timing methods (the other working only with
ancient nVidia drivers, like 4xxx) that measures when the vertical
retrace happens.

-Doug

Attachments:

signature.asc (0.25 KB)

matt at mossholder

Dec 19, 2005, 5:34 AM

Post #9 of 15 (3264 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Mon, 2005-12-19 at 01:31 -0800, Gregorio Gervasio, Jr. wrote:

> >>>>> Matt Mossholder writes:
>
> m> 1) Try and ensure that the TV you intend to purchase does not -require-
> m> HDCP enabled input sources for HDMI or DVI connections before you make a
> m> purchase. This has a number of bad side effects, listed below.
>
>
> Do you know which displays have this requirement? (It seems
> like a poor decision to intentionally not provide backward
> compatibility.)

All I can say is that my Panasonic CT-34WX15 definitely has the issue.
They state in the manual that the TV is not for use with a PC, which
might be something other manufacturers state as well. I did run across
other people saying the same thing about their TVs, but since they
weren't any of the models I was looking at, I didn't keep track of which
ones have the issue.

Sorry,
--Matt

matt at mossholder

Dec 19, 2005, 6:23 AM

Post #10 of 15 (3267 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Mon, 2005-12-19 at 07:53 -0500, Doug Larrick wrote:

> Matt Mossholder wrote:
> > Here are a few links to other people experiencing the VBlank
> > problem. Basically, if I have VBlank enabled, and play back video
> > content with Xv, the system hangs. On further inspection it isn't
> > limited to DVI...
> >
> > http://www.nvnews.net/vbulletin/showthread.php?t=56384
> > <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank>
>
> If I'm understanding correctly, if (in nvidia-settings) "X Server XVideo
> Settings -> Video Texture Adaptor -> Sync to VBlank" is checked, it
> hangs? Then don't do that! Instead, to avoid tearing, uncheck that
> setting, and make sure MythTV is using OpenGL vsync. This is the *only*
> way to get tearing-free, stutter-free playback out of MythTV, because
> it's one of only two video timing methods (the other working only with
> ancient nVidia drivers, like 4xxx) that measures when the vertical
> retrace happens.
>
> -Doug

Doug,
Thanks for pointing out that I am an idiot ;) I had been assuming
that the reason that Myth wasn't using opengl-vsync, even though I had
compiled in the support, was because of the Sync to Vblank settings in
nvidia-settings. Your prompting made me take another look, and realize
that the version of 0.18.1 that I have is missing the defines to enable
OpenGL VBlank syning. Compiling now... and crossing my fingers :)

--Matt

jesse at wingnet

Dec 19, 2005, 6:38 AM

Post #11 of 15 (3260 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

Matt Mossholder wrote:
> On Mon, 2005-12-19 at 07:53 -0500, Doug Larrick wrote:
>> Matt Mossholder wrote:
>> > Here are a few links to other people experiencing the VBlank
>> > problem. Basically, if I have VBlank enabled, and play back video
>> > content with Xv, the system hangs. On further inspection it isn't
>> > limited to DVI...
>> >
>> > http://www.nvnews.net/vbulletin/showthread.php?t=56384
>> > <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank>>
>>
>> If I'm understanding correctly, if (in nvidia-settings) "X Server XVideo
>> Settings -> Video Texture Adaptor -> Sync to VBlank" is checked, it
>> hangs? Then don't do that! Instead, to avoid tearing, uncheck that
>> setting, and make sure MythTV is using OpenGL vsync. This is the *only*
>> way to get tearing-free, stutter-free playback out of MythTV, because
>> it's one of only two video timing methods (the other working only with
>> ancient nVidia drivers, like 4xxx) that measures when the vertical
>> retrace happens.
>>
>> -Doug
>>
>
> Doug,
> Thanks for pointing out that I am an idiot ;) I had been assuming
> that the reason that Myth wasn't using opengl-vsync, even though I had
> compiled in the support, was because of the Sync to Vblank settings
> in nvidia-settings. Your prompting made me take another look, and
> realize that the version of 0.18.1 that I have is missing the defines
> to enable OpenGL VBlank syning. Compiling now... and crossing my
> fingers :)

Is that a configure option? Wondering if it's on by default in Gentoo's
0.18.1 when compiled with nVidia support.

--
Jesse Guardiani
Programmer/Sys Admin
jesse[at]wingnet.net

matt at mossholder

Dec 19, 2005, 7:02 AM

Post #12 of 15 (3266 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Mon, 2005-12-19 at 09:38 -0500, Jesse Guardiani wrote:

> > Doug,
> > Thanks for pointing out that I am an idiot ;) I had been assuming
> > that the reason that Myth wasn't using opengl-vsync, even though I had
> > compiled in the support, was because of the Sync to Vblank settings
> > in nvidia-settings. Your prompting made me take another look, and
> > realize that the version of 0.18.1 that I have is missing the defines
> > to enable OpenGL VBlank syning. Compiling now... and crossing my
> > fingers :)
>
> Is that a configure option? Wondering if it's on by default in Gentoo's
> 0.18.1 when compiled with nVidia support.
>

It is a configure option, but the problem actually lies in
libs/libmythtv/libmythtv.pro. You may need to make this:

using_opengl_vsync {
CONFIG += opengl
}

Look like this:

using_opengl_vsync {
CONFIG += opengl
DEFINES += USING_OPENGL_VSYNC
}

The issue has been addressed in the development version.

--Matt

jarod at wilsonet

Dec 19, 2005, 10:01 AM

Post #13 of 15 (3262 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Monday 19 December 2005 07:02, Matt Mossholder wrote:
> On Mon, 2005-12-19 at 09:38 -0500, Jesse Guardiani wrote:
> > > Doug,
> > > Thanks for pointing out that I am an idiot ;) I had been assuming
> > > that the reason that Myth wasn't using opengl-vsync, even though I had
> > > compiled in the support, was because of the Sync to Vblank settings
> > > in nvidia-settings. Your prompting made me take another look, and
> > > realize that the version of 0.18.1 that I have is missing the defines
> > > to enable OpenGL VBlank syning. Compiling now... and crossing my
> > > fingers :)
> >
> > Is that a configure option? Wondering if it's on by default in Gentoo's
> > 0.18.1 when compiled with nVidia support.

I believe it isn't in -r1, but is in -r2 (~ masked atm), if you have opengl in
your USE flags, but I could be wrong...

> It is a configure option, but the problem actually lies in
> libs/libmythtv/libmythtv.pro. You may need to make this:
>
> using_opengl_vsync {
> CONFIG += opengl
> }
>
> Look like this:
>
> using_opengl_vsync {
> CONFIG += opengl
> DEFINES += USING_OPENGL_VSYNC
> }
>
>
> The issue has been addressed in the development version.

Also fixed in the release-0-18-fixes svn branch, along with the addition of a
patch to make it possible to toggle opengl vsync on and off.

--
Jarod Wilson
jarod[at]wilsonet.com

jason_wilk at stircrazy

Dec 27, 2005, 7:15 AM

Post #14 of 15 (3213 views)
Permalink

RE: Adventures in HDTV - Notes from the trenches [In reply to]

Jarod Wilson wrote:
> On Sunday 18 December 2005 23:26, Yeechang Lee wrote:
>> Steve Adeff <adeffs[at]gmail.com> says:
>>> no HDTV currently accepts 1080p input.
>
> Somebody beat me to the "BS!" call... ;)
>
>> Not many do, but there are some and more such models are coming out
>> each week; the Magnolia Audio/Video I visited last week was
>> highlighting their selection of them. Now, there are a few caveats:
>>
>> * No readily-available source of 1080p content other than computers
>> (including MythTV, natch). Not cable, not over-the-air broadcasts,
>> not videogames. It's likely HD-DVD and Blu-Ray (including the
>> PlayStation 3) will carry 1080p content, though.
>> * TVs that take 1080p input will sometimes restrict them to only a
>> given input port while others only do 1080i.
>> * Some models that claim to do true 1080p, like a certain Sceptre
>> 37", will internally convert to 1080i then convert back to 1080p,
>> or pull some other tricks. Others, like a Westinghouse 37", is
>> said to be true 1080p all the way.
>
> I have said Westinghouse 37" TV, and it most definitely does accept
> and display a GORGEOUS 1080p signal (from a GeForce 6200's DVI port).

Which model is your Westinghouse? The LVM-37w1?

jarod at wilsonet

Dec 27, 2005, 10:41 AM

Post #15 of 15 (3203 views)
Permalink

Re: Adventures in HDTV - Notes from the trenches [In reply to]

On Tuesday 27 December 2005 07:15, jason_wilk[at]stircrazy.net wrote:
> Jarod Wilson wrote:
> > I have said Westinghouse 37" TV, and it most definitely does accept
> > and display a GORGEOUS 1080p signal (from a GeForce 6200's DVI port).
>
> Which model is your Westinghouse? The LVM-37w1?

Yup.

--
Jarod Wilson
jarod[at]wilsonet.com

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