[mythtv-users] OTA ATSC Down-convert to SD/S-Video

[jarpublic at gmail.com]

> I've read that some nVidia cards are known to have overscan problems.  Do
> the binary nVidia drivers solve this problem?  If not, is there a solution?
> I'm confused by the conflicting(dated) information I've found so far.
> Remember, I need to send an analog signal via S-Video to a SD TV.

There was recently a long thread about the overscan issue. Whether it
will be a problem for you depends on your TV. If your TV overscans and
doesn't have anyway to compensate/disable it, then you will probably
have a problem with the newer video cards. When using an old 5200 I
could use nvidia-settings to adjust the overscan to fit my TV.
However, it seems that this features is not available for the new
8xxxx and 9xxx cards with the linux driver. I am not sure if it is all
of these cards or just a large subset up them. But there are people
filing complaints with nividia with many of those cards. It is
possible they will add this back into the drivers but they haven't
done it yet. If you are only using mythtv then you can just adjust the
screen with that screen setup wizard. So it is really only an issue
when you are out of mythtv. I was able to adjust my toolbar size, and
I usually use vnc or ssh when doing anything with the OS (where it
doesn't really matter).

> Does a 512MB video card provide any advantage over a 256MB card for video
> playback?  I won't be using this system for games.

Some have had better success with 512 MB while others have got things
working fine with 256 MB, plus it is a moving target as they are
improving things for less capable cards with driver updates. So 512 is
probably safer but might not be necessary.

>
> Here is the build that I'm thinking about at the moment...
>
> Motherboard: (1 of them)
>  ASUS M3N78-EM
>  ASUS M3N78 PRO
>  Both contain:
>    - NVIDIA GeForce 8300 (North Bridge)
>    - NVIDIA GeForce 8 series (video) - VGA, DVI, HDMI
>    - Realtek ALC1200 (Audio) - S/PDIF (coaxial or optical), 6 Audio Ports
>    - Realtek 8211CL (Network)
>

I just built a system with the M3n78-EM and I haven't had any problems
with it. Everything worked out of the box. Granted, just like you I
plan on using the onboard video later when I get an HDMI TV.

> Video Card (1 of them for purpose of S-Video out):
>  ASUS EN8400GS SILENT/HTP/512M GeForce 8400 GS 512MB 64-bit GDDR2 PCI Express x16
>  ASUS EN8400GS SILENT/HTP/256M GeForce 8400 GS 256MB 64-bit GDDR2 PCI Express x16 HDCP
>  EVGA 512-P2-N738-LR GeForce 8400 GS 512MB 64-bit GDDR2 PCI Express x16 HDCP Ready

I got the EN8400GS 256 MB because the 512 was out of stock and my
current system had died, so I didn't want to wait for it to come back
in stock. I have installed mythtv and the nvidia 180 drivers from
Jean-Yves's repository. VDPAU works perfectly for SD content. I have
enabled the advanced 2x deinterlacers and things look much better on
even on my SD set. I don't know if those would be able to do the
advanced 2x deinterlacers for your HD recordings going to SD output.
But they all should have no problem doing the decoding on the GPU and
using one of the less computational deinterlacers.

> Will I regret not spending the extra $100 on a HTPC case?

I went with a cheaper case because I thought the 120mm fans wouldn't
be very noisy if I spin them slowly. I ended up unplugging one of the
case fans because there is only pwm controller for 1 case fan and 1
cpu fan on that motherboard, so the other fan would spin full speed.
With lm-sensors and fancontrol (which is really easy with ubuntu) I
have the fans spinning acceptably slow so the noise is tolerable. If
you go that route, take note that the CPU and M/B temps are reported
swapped by lm-sensors on this board (you can fix in the setup file). I
was amazed at how long it took me (ie how stupid I was) to figure out
why my MB temp shot through the roof and my CPU temp sat steady when I
loaded the system.  but I am still considering getting some quieter
fans which may cost me another $20-30. So I may have just been better
of getting a quieter case or at least getting some quieter fans to
start with.

>
> Are there any heat concerns I'd need to be worried about GPU heat when
> VDPAU support is included in a myth release? (or I get comfortable enough
> to run what is on SVN) -- I've tried to pick nVidia parts listed on Myth
> VDPAU page?

I have only been doing SD content but my card only gets up to 53
degrees C after running for a long time with VDPAU. I think most
nvidia cards can handle upwards of 70 without a problem. I know on
their higher end gaming cards you don't need to worry until about 90.
You can check nvidia-settings if you are worried, at 53 it was at the
bottom of their temp gauge. HD will probably tax it more but I haven't
heard of heat problems.