[mythtv-users] CBS HD content suddenly doesn't play

jedi jedi at mishnet.org
Fri Feb 13 22:56:10 UTC 2009


On Fri, Feb 13, 2009 at 02:26:01PM -0800, Brad Fuller wrote:
> On Fri, Feb 13, 2009 at 1:57 PM, jedi <jedi at mishnet.org> wrote:
> >    I've been able to play CBS stuff with the internal player on the ATV.
> > I recently watched some HD episodes of The Unit recorded off the air with
> > my HDHR on the ATV with no problem.
> >
> >    The ATV has serious network issues if it isn't setup right. HD material
> > can easily choke on this before the box has a CPU issue.
> 
> I've always had problems playing CBS, but only CBS on ATV.
> Perhaps I have network issues. What can I do to check?

    Run a network speed test. Log onto the box and do a file
transfer to some known good host. A network issue will be
readily apparent.

    1080i mpeg2 files are BIG. You need a lot of network mojo
to push them around and stream them. When the ATV goes into
ACPI cpu state C3 network performance goes to crap.

    I have mine forced to C1.

Here is the relevant bit from the atv-bootloader forum:
-------------------------------------------------------


>I have an older ApptleTV. From the very beginning I've had problems
>with my network card. I am currently upgrading my MythTV from .20 to .
>21 and it'll take more than an hour and a half to download the updates
>since the connection is running at 5k/s. I have a fiber-optic line and
>the other computers on my network download at more than 1000x that
>speed.

>The RX line, "RX packets:259004 errors:23530 dropped:45103 overruns:
>23530 frame:0", shows a bunch of errors. The weird thing is that when
>I stream HD, it has no problem keeping up and the errors go away.

>Is anyone else having this problem? Any ideas on how to solve it?

Someone else has seen slow network performance when just coping files
over the network. This fix is kernel dependent as the kernel gods
removed it under the 2.6.24 kernels (it's coming back).

If you check the cpu power state (C1, C2 C3). You should see that the
states are active and goes to C3 when idle.

"cat /proc/acpi/processor/CPU0/power"

Force the min cpu state to C1 or C2. The latency from C3 to C2/C1 is
long and I guess the network driver can't keep up until it's in C2 or
C1.

su root
"echo 2 > /sys/module/processor/parameters/max_cstate"

To make this change at boot, two ways, add this line to
"/etc/modprobe.d/options". this might work for 2.6.24 kernels too.

options processor max_cstate=2

Or add this to "/etc/rc.local"

"echo 1 > /sys/module/processor/parameters/max_cstate" 


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