[mythtv-users] Advice for VDPAU and HD-PVR

john jppoet at gmail.com
Thu Dec 25 04:48:51 UTC 2008

On Dec 24, 2008, at 5:32 PM, Michael Tiller wrote:

> So I got an HD-PVR for Christmas.  I also asked for and got an  
> NVIDIA 8400GS expecting that my system won't be able to play back  
> the recordings very nicely.
> As I see it, I have several choices:
> Wait until 0.22 and have both HD-PVR and VDPAU support in that.
> Install 0.21-fixes + HD-PVR support as a patch (I assume this is  
> available, I saw something about it).
> Upgrade to trunk (and the associated instability)
> So, #1 is just no fun and since there is no release date, that could  
> take a very long time.
> The issue with #2 is that without VDPAU support, I'm likely only  
> going to be able to capture at faily low rates for now which is a  
> bit of a downer but also safer.
> With #3, I have the headache of really messing things up.  However,  
> as far as I can tell it is the only path to getting both HD-PVR and  
> VDPAU support.
> So here are some questions...
> First, am I missing anything?  For example, if somebody had created  
> some .deb files for a version of MythTV from the trunk that had just  
> what I needed and was relatively stable then that would be the  
> simplest for me.  I'm guessing that doesn't exist.
> Second, is #2 a viable solution?  I thought I saw a thread (although  
> I can't find it now?) saying that there was some issue with applying  
> the HD-PVR patches to the fixes branch.

The patch available to add HD-PVR support to 0.21-fixes is not  
officially supported.  So, if you apply it, you are completely on your  
own.  No one will be willing to help you with any problems you may have.

When upgrading from one version of Myth to another there are always  
changes to the database structure.  If you apply that patch against  
0.21-fixes, you will end up with a database which Myth will not be  
able to upgrade automatically.  When 0.22 does come out, you will  
either have to start from scratch, or update the database structure by  

> Finally, if I wanted to go with #3 does anybody have a suggested  
> revision to build?  What I'm looking for is somebody to say "I run  
> VDPAU and HD-PVR support from rXXXXX" and it works great, where  
> XXXXX is not the head of the trunk.  I'm not so eager to be on the  
> bleeding edge so if there is something relatively stable back up the  
> trunk that gives me what I want then I would totally go for that.

Trunk has been unstable for a very long time.  It segfaults more than  
the fixes branch.  It has LOTS of visual/theme problems, because that  
entire mechanism is being re-written.  If there was a point when trunk  
was stable, it would have probably been released as 0.21.1 or 0.22.   
If you want to go with trunk, just grab the latest and hope it works  
for you.

I use trunk for my production machine because I want to use the HD-PVR  
with it.  For me, it is worth some problems to be able to use the HD- 
PVR.  HOWEVER, I know c++ and how to use gdb.  I know how to diagnose  
and report problems -- or alternately, fix them myself.

I can say that trunk mythbackend is pretty stable -- as long as you  
don't use slave backends.   At least at one point, slave backends  
could cause master backends to "lock up".  Been a few months since I  
tried that configuration, so I don't know if that is still the case.   
I run two HDhomeruns and two HD-PVRs and only miss recordings on a  
very rare basis.

Trunk frontend has more issues.  Watching HD-PVR recordings will cause  
a unreproducible segfault in about 1 out of 10 shows watched.   
Watching HDhomerun recordings is problem free.  Theme wise, there is  
some ugliness -- some parts of the user interface use the new mythui  
code and some parts still use the old code, and some parts are half  
way in between.

VDPAU is still HIGHLY experimental.  I sometimes have to restart X, or  
even reboot the frontend machine to recover from some of the VDPAU  
glitches.  It is getting better, thought.  Each new nVidia *beta*  
driver has been an improvement.

> I subscribed to -commits and -devs so I'm watching that as well.

If you decide to go with trunk, you cannot expect a bug-free  
experience.  Any cries for help will be met with disdain unless you  
know how to properly file a bug report -- in other words, how to use  
gdb to get a viable backtrace.  In general, bug reports relating to  
VDPAU are rejected because it is too early to expect it to work in myth.

So, have I scared you off of trunk yet?

Unless you are willing to ditch all of your recording and start over  
when 0.22 comes out, I would avoid option 2.  There is a chance that  
the person that wrote the patch against 0.21-fixes will also write a  
program to "fix" the database, but I would not count on it.

I understand the desire to make use of the HD-PVR, but you need to  
understand the cost.


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