[mythtv-users] MYthTV Playback is Choppy

[Brian Wood]

On Tuesday 07 April 2009 08:04:57 Brian Schmidt wrote:
> I'm running the latest stable MythTV updated via yum on a Fedora Core 10
> box. The machine is a Shuttle PC that is multiple years old. It has the
> nForce2 chipset. I'm running the latest 96.43 Nvidia drivers also updated
> via yum. The TV output is functional and is using the Nvidia drivers (the
> Nvidia logo appears as X starts). I'm running Xorg and Gnome. I have a
> Hauppage HVR-1600 installed and I'm receiving over-the-air ATSC digital
> broadcasts in NTSC format.
>
> At first I thought the issue was the CPU and memory of my older system.
> However, I can record shows without issue and I can play them back without
> issue using mplayer. The only time my playback is choppy is when I use Myth
> to play the recorded TV show back. I've been searching through the mailing
> list archives and other forums for a few weeks, but I haven't been able to
> resolve the issue. My best results have come when having Myth configured to
> use libmpeg for decoding and chromakey for the OSD. I've tried different
> deinterlacers and I've had mixed results. I've also followed the Optimizing
> Performance on the Myth wiki along with the "Hacking MythTV" book.
>
> Another thing to note is that I can't seem to set any resolution other than
> 1024. This box is for my parents and they do not have an HD TV, so I'm fine
> with running a lower res and was hoping that might help, but X refuses and
> keeps automatically switching back to 1024.
>
> I appreciate any help that anyone can offer me. Previously, this system was
> up and running using an older version of Myth and a Hauppage analog-only
> card.

You didn't mention what your hardware actually is, beyond the mobo chipset.

Playing back with Myth requires more resources than doing so with mplayer, and 
it's possible you are on the edge. What is your CPU usage when playing back? 
Are you swapping?

There are things you can do to reduce load, such as running a lightweight 
window manager (or no window manager), Gnome is pretty resource intensive. 
Putting your OS and database on a separate drive from your video storage can 
also help.

It certainly sounds as if you are running into some limiting factor in your 
system performance, you need to identify what it is.

-- 
beww
beww at beww.org