[mythtv-users] Xorg nouveau driver vs. nvidia-driver

Ram Ramesh rramesh2400 at gmail.com
Thu Nov 5 17:35:16 UTC 2020

On 11/4/20 11:04 PM, Stephen Worthington wrote:
> On Wed, 4 Nov 2020 13:13:02 -0600, you wrote:
>> Hi,
>>    I am running mythtv 31-fixes on Debian Buster (10) through
>> deb-multimedia backports. I started with Nouveau driver for Xorg as that
>> is the default in Debian buster.  After testing a while and making sure
>> that it works, I added nvidia-driver.  While mythfrontend seem to look
>> tiny bit better, I see that gui is not fitting due to overscan on TV.
>> It was perfect with nouveau driver and overscanned on nvidia-driver.
>> Another thing I noticed is nouveau drive gives me 1920x1080 at 120hz
>> whereas nvidia does 1920x1080 at 119.88hz. Not sure if nouveau is rouding
>> or giving me a true 120hz. I do see that my TV takes a while when
>> switching from another source to mythtv host when in 119.88hz rating.
>> Given this,
>> Is nvidia-driver known to be superior that I should try to keep it and
>> adjust frontend gui resolution to make things fit or should I simply
>> switch back to nouveau driver?
>> Also, overscan is a general issue even with Xorg, and fixing gui
>> resolution will not make Xorg better. I will have to fix Xorg overscan
>> somehow. So, I prefer nouveau over nvidia in this aspect.
> I think you are confusing things here.  Nouveau uses X in the form of
> Xorg just as Nvidia does.  And the overscan problem is usually in the
> TV, not the video drivers.  And to complicate things further, the
> Nouveau drivers do now have some VDPAU abilities so they can offload
> some things onto the GPU for video playback.
>> Any help suggestion in improving what I have is much appreciated.
>> Thanks
>> Ramesh
> I used Nouveau last year on my first GT1030 for a while.  That PC has
> an ancient motherboard (Intel Core2 Duo E6550, from 2008) and only 4
> Gibytes of RAM.  So it needs the graphics processing to be done by the
> GPU.  It was fine for desktop use, but mythfrontend could not play any
> TV successfully.  Even SD recordings (576p) seemed to judder a bit as
> though there were dropped frames.  And HD (720p, 1080i) was impossible
> to watch.  Installing the Nvidia drivers made everything work
> properly.  If you have a fast modern CPU, it may be able to do the
> graphics processing fast enough in the CPU with the Nouveau drivers,
> but where you normally see problems is in deinterlacing.  So try
> playing 1080i recordings, and watch scenes where there is fast
> panning.
> And it is unlikely that any 4k video will work properly.  I found that
> on my main MythTV box with a GT220 (no 4k support), the CPU was unable
> to rescale 4k downloaded video to 1080p.  When I changed it to a
> GT1030 also, 4k rescaled on the GPU without any problems.
> So, which Nvidia card are you using?  And just what is your TV?  If it
> is 4k, then you definitely will want to be using the Nvidia drivers. I
> would recommend using Nvidia anyway - it uses much less electricity to
> use the GPU instead of the CPU for graphics processing.
> You should check if your TV can be set to have its overscan disabled.
I thought I did, but since you mention here, I went back and searched 
all over the menu. It is under one of the submenu. It is called "fit to 
screen" and it was set to auto. Last time I must not have tried all 
options. I changed it "on" instead of "auto," and voila! everything 
looks good now.

Thanks for your help.


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