[mythtv-users] HD-PVR issues - is there a solution?

John P Poet jppoet at gmail.com
Wed Feb 23 00:58:52 UTC 2011

On Tue, Feb 22, 2011 at 5:09 PM, Mark <fairlane at springcom.com> wrote:
> I've searched the web high and low for weeks and have yet to get a
> definitive set of answers on the HD-PVR issues as they stand.  Lots of
> people seem to have the same issues.
> 1.  Zero byte files - usually requires a reset

I get this, but very rarely.  Usually the cause (for me) is the
channel change on my Directv STB failed for some reason.  Still trying
to figure out why that happens, and what needs to be done about it.

> 2.  Unit stops responding - always requires a reset

This happens to me about once every 3 to 7 weeks.  I have been trying
to come up with a way to "reset" the HD-PVR in software, but have not
had any luck so far -- partially because it happens so rarely to me.

> 3.  Audio records at 59.94Hz, and video at 60Hz, giving a sync issue over
> time.  Some people change firmware to fix it, only to return to the same
> state.  Is this a firmware issue or a myth issue?  Who knows?

I believe this is very STB specific.  For example. people on DISH seem
to have this problem, but I don't.

> I'd like to try and collect all this information in one place / thread to
> give folks out there struggling with the same issues a place to get
> answers.  There's got to be a fair amount of people who've experienced
> these issues.  Let them come forth and share experiences!
> And finally, if there's no solutions to these issues, let's do what we
> need to do to fix them.  Bug reports, traces, whatever it takes.

Myth absolutely could be better about handling hardware errors.  The
problem is that it is hard to test the error recovery when you (I)
can't *make* the error happen.

I have two HD-PVRs.  One is very old (a rev c2) and the other is only
about a year old.  My newer one is pretty solid.  My older one will
occasionally stop feeding data in the middle of a recording, but Myth
will automatically recover from that (It does result in a loss of a
couple of seconds out of the middle of the show, though).

I have read that at least one person has seen his HD-PVR stop
"recording" when the S/PDIF supplied audio changed from 5.1 to 2.0 (or
visa-versa).  This can happen when the show goes to commercial and
back.  I have not determined if that is what is happening to me, or

Possible issues that could effect some users and not others:
1) USB ports.  How many devices are hooked up and contending?  How
reliable is the USB chip-set?
2) Computer speed.  Does the computer have the spare I/O cycles to
handle and process the data from the HD-PVR?
3) STB.  How "clean" is the video/audio from the STB?  Is the STB
responsible for any glitches?
4) ???

Telling the HD-PVR to "record" when the STB is sending out garbage
(during a channel change, for example) can result in the HD-PVR
getting confused.  This is why some people are able to reduce their
problems by adding a sleep at the end of their channel change scripts.
 Myth 0.24 *tries* to alleviate the need for that sleep by verifying
the data from the HD-PVR (after a channel change) before it starts
actually "recording" the show.  To verify the data, Myth tries to read
from the HD-PVR and once it is able to read any data, it then queries
the HD-PVR for the video resolution.  Once Myth is able to get a valid
video resolution from the HD-PVR, it assumes that the STB is producing
clean data, and allows the recording process to start.

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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