[mythtv-users] MythTV video output is degraded by Subsonic installation

[Joseph Fry]

>
>
> OK, this is a strange one - I have no idea what's happening here.
>
> I have a MythTV 0.25-fixes BE/FE system running on a desktop PC with 3.1
> GHz dual-core Athlon, 4 GB RAM, Mythbuntu 12.04, and an NVidia GT 430 video
> card with VDPAU hardware video acceleration. The system is used primarily
> as a MythTV system for TV recording (HDHR) and playback. It drives a
> 47-inch LG LED TV by HDMI. The video quality on MythTV HD playback is just
> about perfect.
>
> Then I installed Subsonic 4.7 ( http://subsonic.org ) on the same machine
> last weekend. Subsonic is software that allows audio and video streaming,
> and I use it mostly to stream audio to my workplace over the internet.
>
> But the video quality during MythTV FE playback on the TV that's hooked
> directly to the PC by HDMI was very noticeably degraded by the Subsonic
> installation: I started getting very noticeable frame-tearing:
>
> http://www.mythtv.org/wiki/Frame_display_timing
>
> This had never happened before. I stopped the Subsonic service and I still
> got tearing. Then I logged out and back in (I guess this restarts the X
> window system but does not restart the Subsonic service). This took care of
> it: no more tearing - the MythTV video on the attached TV was back to its
> previous excellent state.
>
> So Subsonic is somehow interfering with and degrading MythTV video
> playback on the attached TV.
>
> This process is 100% repeatable: launch Subsonic and the MythTV video
> output is very noticeably degraded. Stop Subsonic, then log out and back
> in, and MythTV video output on the attached TV is perfect again.
>
> I have already posted this to the Subsonic forum several days ago, and I
> got zero response. Are there any MythTV users out there who are also
> running Subsonic on the same machine? If so, do you have degraded video
> quality?
>
> Any ideas what's happening here? Any chance that this might be fixed? Or a
> workaround?
>
>
I would begin by making sure your frontend is using realtime threads:
http://www.mythtv.org/wiki/Optimizing_Performance#Realtime_Threads.  What
may be happening is that the new software is competing with mythtv for
processor cycles... some software just does that, usually a sign of poor
code.

Another thing you might check is to see is if subsonic is indexing content
on first run... a process like that could easily take a couple hours, use
very little CPU, yet cause a lot of IO.
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