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TV-Out
This is ancient content left over for reference and achival purposes;
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Several graphics cards offer output to TV. Also scan converters can send video from almost any graphics card to TV. The quality differences between products can be extreme. Black borders, blurry pictures, inconvenient use are the most common problems.
Many older solutions did require to play the video full screen and set certain resolutions and refresh rates, which is quite inconvenient.
Matrox DualHead cards were the first to solve the problem
and offer ultimate flexibility:
G400 DualHead, Matrox G450 and G550 can send any content of a
DirectShow Windows (like MediaPlayer and other video player software)
to a TV, where the resolution and refresh rate of the video are
completely independent of the main computer monitor and of the
player window size.
The feature is called 'DVD-Max'. No matter how you resize the
player or TV application window, with some players even if you
cover it under other windows, video will be playing full quality
on your TV while you may be editing documents, surfing the web
or doing anything else with your PC.
Even interlaced material plays perfectly on the TV. Absolutely
no resizing occurs, and crispness is 100%. It also works with
DVBviewer minimized, for example, with no jerkiness at all.
The results were obtained with a G400 DualHead 16MB, DVBviewer,
and the MPEG codecs from WinDVD5.
It may be necessary to fiddle with the registry to make interlacing
work (changing HKEY_LOCAL_MACHINE\SOFTWARE\InterVideo\Common\VideoDec\BOBWEAVE
from 0 to 2; the key name may be different according to the particular
installation.
Except for the very expensive Parhelia
cards, Matrox cards have no IDCT-support, so MPEG decoding requires
a lot more CPU load. Expect about 40% on a 2.4 GHz CPU vs. 20%
with a card that has IDCT (Inverse Discrete Cosine
Transform).
HDTV therefore is a bit jerky, at 100% CPU.
With TV-out enabled however, there is no difference to the Radeon
cards, for example, that have IDCT: The Radeons then cause the
same CPU load as the Matrox. This also holds for HDTV with (downscaled)
TV-output.
Running other applications simultaneously however causes the TV-output
to stutter. This is much less a problem with Radeons, despite
of the almost equal CPU useage.
The (discontinued) G400 has an advantage
for European users: Most TVs here have SCART plugs, and the G400
can deliver RGB signals to it, so any signal loss involved with
the color carrier is eliminated. You need a proper adapter cable for this.
On a normal TV however, don't expect too much from it.
I have to admit that sometimes the TV
output may be staggering a bit for a while for no obvious reason.
It greatly depends on codecs and players used. MS MPEG4 and DivX;-)
3.x do that sometimes, while DivX4 and most DVD players don't.
ATI's Radeon 7500,8500,8500DV, 9200, 9500 etc. now do have a function
much like Matrox' DVDmax, which can send videos playing in a window
(or even a minimized application) to the TV, in full size and
resolution. They also have IDCT, which makes HDTV playback work
better (smooth playback with HDTV and TV-out only worked
here with the older 2.5 drivers and the dedicated Cypberlink/ATI
decoder, see below)),
and they have more gaming capabilities than the Matrox G series.
CPU load was 20% for PAL standard and 60% for European HDTV (1920x1080
interlaced) on a 2.4 GHz machine. Decoders used were from PowerDVD5
or from the ATI CD (Cyberlink/ATI).
Disadvantage: I couldn't get the TV-out
to reproduce interlacing. The picture is also a bit unsharp, not
as good as the original TV or, for example, the TV-out of a Matrox.
Obviously, even with TV overscan enabled, the driver does not
yield an unscaled picture. Even swapping the Radeon with the Matrox
and comparing exactly identical applications and codecs simply
revealed that the Radeon couldn't do interlacing. This is not
a 100% solution. It may be OK for presentations, because the driver
seamlessly switches from desktop cloning to theater mode, but
using the TVout for TV viewing is nor recommendable this way.
Matrox provides a much better TVout picture with the normal format.
What is better with the Radeon is that TV-out is much less likely
to stutter when other applications are started. It is therefore
quite good if one wants to watch TV on a second screen while working.
To cut and edit video with TV screen control, a Matrox is better
because its TV output is really 1:1, with full crispness and interlacing
retained.
What is necessary to unveil all capabilities of a Radeon card are newer drivers. I checked this with the 5.1 and 5.5 drivers from ATI's website under Windows2000, with a Radeon 7500 as well as a Radeon 9200 vivo. These drivers also natively support TV 'overscan'. The best experiences I had with the 5.5 drivers so far, under WIndows 2000 and XP. Later drivers come with a new catalyst control center that wastes resources, doesn't work properly if you use big screen fonts and looks like one of these games. At guru3d.com you can find some later versions combined with the old control center.
The driver docs aren't really helpful:
All ATI docs state that the PC screen will have to be switched
to 50 Hz for PAL TV-out. Very misleading (only the boot screen
display will become 50 Hz when a TV is connected). You can use
any site and refresh rate, the only restriction is that only a
section of at most 1024x768 can be transferred to the TV. But
that can be dynamically moved around with the mouse.
This is only one of the inaccuracies in the docs. Another problem
is that the TV-out options are not well explained at all.
If you want to update (or downgrade)
ATI drivers: Simply deinstall "ATI Control Panel" only,
then reboot, then install the new ones.
To activate video to TV cloning: Right click on Desktop, ->Settings
->Extended ->Overlay, select "Theater Modus".
What model to use ?
I could not find any difference between the 7500 and the 9200,
and probably it's the same with other models, at least for this
type of use. CPU loads for MPEG playback, and, for example, with
MS Flight Simulator 2000, were identical. Normal desktop display
is perfect (110% identical with a Matrox), so the only differences
are probably with newer 3D Games, something that I totally ignore.
So for video, it really does not seem to matter, a cheap card
would do it.
I even got better performance with MS Flight Simulator 2000 on
the 7500 and the older 2.5 drivers that don't work for the 9200.
It reqired some tuning of FS's settings to get the newer drivers
to work about as well. Most important, Radeon cards like 32 bit
colors better than 16 bit. Also distant detail settings are a
bit critical in FS.
Some Overscan for the TV-output
can be activated for the 2.5 driver by adding a registry key like
this (key may vary according to installation):
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ati2mtag\Device0]
"TVEnableOverscan"=dword:00000001
You can also enforce TV-out
even if the TV is not there or has a high input resistance (this
one doesn't work under WIndows XP):
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ati2mtag\Device0]
"TVForceDetection"=dword:00000001
With the newer card models, use some 5.x driver version.
TV-out from HDTV should work smoothly
(!), if I use the Cyberlink decoder "/ATI" that was
on the ATI driver CD of the card (install "DVDDcdr").
Sometimes it doesn't, try other driver versions if you encounter
such a problem.
You may be able to achieve the same result with the decoder from
PowerDVD (at least verion 5) if the ATI variety is not in reach,
but there is no necessity to try this only because these decoders
are a bit "newer" than the /ATI versions, quality wise
I could not see any difference.
Nvidia (Geforce) cards with TwinView and newer drivers are reportedly now also able to do the TV-out trick correctly. However I have none and can't say any more about it.
Conclusion
If you want perfect TV quality, a Matrox G400,450 or 550 (Double Head) would do it, despite of the fact that it needs more CPU power because it has no IDCT support. The G400 also has an RGB output.
Radeon cards need less CPU power and even allow to downscale HDTV (viewing full HDTV on the computer monitor while simultaneously sending the picture to a standard TV), but the TV picture is always going through the scaler even with normal TV programs (even with overscan enabled) and it is always deinterlaced.
The 3rd variety would be a Radeon card
tuned to TV standard resoulution and directly RGB connected from
its VGA output to the SCART plug of a (European) TV. This is for
dedicated home theater PCs only.
For some hints about TV-output together with DVB reception, see the DVB page
Some links to test sites:
Gainward CARDEXpert GF2MX TwinView GS
Some Utilities for the cards:
DivXG400
A must-have.
This is a little filter for Matrox G400/G450/G550 DualHead cards
(and others) that enables TV-out also for videos 720 pixels wide
(or other formats that are not a multiple of 32). This has always
been a problem with MPEG4, MJPEG, MSMedia7 and 8, and DV codecs
except Microsoft's. This is not a codec but a filter. Works with
Media Player 6.4 (not 7) and any codec.
This filter is also
useful for ANY other graphics card because the overlay bug is
always present with Media Player (6.x as well as 7) and also prevents
decent fullscreen view of 720 wide movies in any case
The newest version also has other features like 'play near 25
fps video at 25 fps'. which may reduce staggering with TV-out.
Cable layout for Matrox RGB to SCART:
|
SCART male connector pin |
Signal |
VGA 15pin male connector pin |
| 15 | Red | 1 |
| 13 | Red ground | 6 |
| 11 | Green | 2 |
| 9 | Green ground | 7 |
| 7 | Blue | 3 |
| 5 | Blue ground | 8 |
| 20 | Composite/Sync |
4 (G400) 14 (G450/550) |
| 17 | Composite/Sync ground | 5 |
| 16 |
(connect by a 75 Ohms Resistor) |
9 (G450/G550) 13 (G400) |
| 12 shorted with 15 | ||
| Connector case | Cable shield | Connector case |
Optional audio connection to SCART:
|
SCART male connector pin |
Signal |
Sound card phono jack |
| 6 | Left channel | tip |
| 2 | Right channel | middle |
| 4 | Ground | shaft |
Pins 12 and 15 of the VGA connector must
be shortcut, to inform G400 about the TV connection.
In case of RGB only, you may try a 680 Ohms resistor in the composite/sync
line if the sync signal is too strong for the TV.
The video cable may use a common shield (= ground) for lengths
up to about 8 ft., because crosstalk between the signals is not
so critical in this case.
For the audio, use a separate cable with separate shields.
One last hint: You
have to reboot with the cable connected, in order to make the
TV-output work !
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