Mailing List Archive

Re: [mythtv-commits] Ticket #1153: Live TV : "Error was encountered while displaying video."
On Thu, 2006-08-17 at 09:40 -0400, Mark Buechler wrote:
> I've seen this as well. As Daniel probably already knows, this message
> appears when the backend stops recording frames for a period of time,
> but not in all cases. I've seen this happen when the backend tunes a
> channel which is encrypted and can't be decrypted. I've also seen on
> occasion the backend just stops responded entirely and has to be
> restarted. The problem also used to exist when the backend switches
> ringbuffers between programs. I haven't seen that particular problem
> in many versions now, however.

The "Error was encountered while displaying video" message is
a catch all for a large number of different types of error
conditions. The most common is when there is a timeout waiting
for video to start for whatever reason. The timeout is not
supposed to start counting until we have a good signal. This
can fail if the recorder does not have a signal monitor, if
the signal is encrypted, or if the signal disappears after
the signal monitor reports that it is good. The first two need
to be fixed, the last one can't be fixed on all hardware, but
we've talked about fixing it with some hardware.

This can also happen if you flip channels very quickly. Fixing that
problem is a long term project because we don't count frames in the
NVP, we count bytes, and this sometimes fails. Counting frames depends
on fixing #799, and some display problems I'm working on on the
mythtv-vid branch. A quick fix would be to just limit you to one
channel change every two minutes, but I think that is not a good
solution since 99% of the time for a DVB-T/DVB-C or ATSC/QAM user
a channel change completes in 1-3 seconds.

There was another problem in 0.19 that made the quick succession of
channel changes especially sensitive to frame count estimation
errors, which was the problem which the logs in ticket #1153
showed. This problem was worked around by Issac in SVN head, and
hence the closing of the ticket. The underlying problem with the
estimation throwing off ring buffer switching is still there,
but usually only triggered by aggressive channel flipping, and on
very rare occasion when we move from one program to the next in
LiveTV.

-- Daniel

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Re: [mythtv-commits] Ticket #1153: Live TV : "Error was encountered while displaying video." [ In reply to ]
Thanks for the well detailed explanation, Daniel. This really helps quite a
bit with understanding what's going on behind the scenes. Now knowing what
causes it I'm sure I can more easily avoid it.

- Mark.

On 8/17/06, Daniel Kristjansson <danielk@cuymedia.net> wrote:
>
> On Thu, 2006-08-17 at 09:40 -0400, Mark Buechler wrote:
> > I've seen this as well. As Daniel probably already knows, this message
> > appears when the backend stops recording frames for a period of time,
> > but not in all cases. I've seen this happen when the backend tunes a
> > channel which is encrypted and can't be decrypted. I've also seen on
> > occasion the backend just stops responded entirely and has to be
> > restarted. The problem also used to exist when the backend switches
> > ringbuffers between programs. I haven't seen that particular problem
> > in many versions now, however.
>
> The "Error was encountered while displaying video" message is
> a catch all for a large number of different types of error
> conditions. The most common is when there is a timeout waiting
> for video to start for whatever reason. The timeout is not
> supposed to start counting until we have a good signal. This
> can fail if the recorder does not have a signal monitor, if
> the signal is encrypted, or if the signal disappears after
> the signal monitor reports that it is good. The first two need
> to be fixed, the last one can't be fixed on all hardware, but
> we've talked about fixing it with some hardware.
>
> This can also happen if you flip channels very quickly. Fixing that
> problem is a long term project because we don't count frames in the
> NVP, we count bytes, and this sometimes fails. Counting frames depends
> on fixing #799, and some display problems I'm working on on the
> mythtv-vid branch. A quick fix would be to just limit you to one
> channel change every two minutes, but I think that is not a good
> solution since 99% of the time for a DVB-T/DVB-C or ATSC/QAM user
> a channel change completes in 1-3 seconds.
>
> There was another problem in 0.19 that made the quick succession of
> channel changes especially sensitive to frame count estimation
> errors, which was the problem which the logs in ticket #1153
> showed. This problem was worked around by Issac in SVN head, and
> hence the closing of the ticket. The underlying problem with the
> estimation throwing off ring buffer switching is still there,
> but usually only triggered by aggressive channel flipping, and on
> very rare occasion when we move from one program to the next in
> LiveTV.
>
> -- Daniel
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev@mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
>
Re: [mythtv-commits] Ticket #1153: Live TV : "Error was encountered while displaying video." [ In reply to ]
On 18/08/06, Daniel Kristjansson <danielk@cuymedia.net> wrote:
>
> On Thu, 2006-08-17 at 09:40 -0400, Mark Buechler wrote:
> > I've seen this as well. As Daniel probably already knows, this message
> > appears when the backend stops recording frames for a period of time,
> > but not in all cases. I've seen this happen when the backend tunes a
> > channel which is encrypted and can't be decrypted. I've also seen on
> > occasion the backend just stops responded entirely and has to be
> > restarted. The problem also used to exist when the backend switches
> > ringbuffers between programs. I haven't seen that particular problem
> > in many versions now, however.
>
> The "Error was encountered while displaying video" message is
> a catch all for a large number of different types of error
> conditions. The most common is when there is a timeout waiting
> for video to start for whatever reason. The timeout is not
> supposed to start counting until we have a good signal. This
> can fail if the recorder does not have a signal monitor, if
> the signal is encrypted, or if the signal disappears after
> the signal monitor reports that it is good. The first two need
> to be fixed, the last one can't be fixed on all hardware, but
> we've talked about fixing it with some hardware.
>
> This can also happen if you flip channels very quickly. Fixing that
> problem is a long term project because we don't count frames in the
> NVP, we count bytes, and this sometimes fails. Counting frames depends
> on fixing #799, and some display problems I'm working on on the
> mythtv-vid branch. A quick fix would be to just limit you to one
> channel change every two minutes, but I think that is not a good
> solution since 99% of the time for a DVB-T/DVB-C or ATSC/QAM user
> a channel change completes in 1-3 seconds.
>
> There was another problem in 0.19 that made the quick succession of
> channel changes especially sensitive to frame count estimation
> errors, which was the problem which the logs in ticket #1153
> showed. This problem was worked around by Issac in SVN head, and
> hence the closing of the ticket. The underlying problem with the
> estimation throwing off ring buffer switching is still there,
> but usually only triggered by aggressive channel flipping, and on
> very rare occasion when we move from one program to the next in
> LiveTV.
>
> -- Daniel
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev@mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
>

Hi Daniel,

Thanks for your detailed description.

However, the only time I see this is when I'm just watching LiveTV - I'm not
changing channels or any thing.

Its quite annoying because it always happens on program boundaries - where
one program ends and the other starts,
however its more to do with what time the programs are supposed to start/end
rather than the actual time. Often
a program will over-run by 30 seconds or so meaning that when this error
occurs my wife misses the last dramatic
moments of East Enders etc. and she's not best pleased :-)

I'm currently running SVN head 10667, which I haven't updated for a while as
I'm waiting on 0.20 and Kernel 2.18.0
but when I do I'll see if the error still occurs, and if it does I will
provide lots of log info if that helps.

Regards
--
Brad.
Re: [mythtv-commits] Ticket #1153: Live TV : "Error was encountered while displaying video." [ In reply to ]
On 01/09/06, MythTV <mythtv@cvs.mythtv.org> wrote:
>
> #1153: Live TV : "Error was encountered while displaying video."
>
> -----------------------------+----------------------------------------------
> Reporter: ben@vanilla.net | Owner: ijr
> Type: defect | Status: reopened
> Priority: minor | Milestone: unknown
> Component: mythtv | Version: head
> Severity: medium | Resolution:
>
> -----------------------------+----------------------------------------------
> Changes (by anonymous):
>
> * milestone: 0.19.1 => unknown
>
> --
> Ticket URL: <http://svn.mythtv.org/trac/ticket/1153#comment:27>
> MythTV <http://www.mythtv.org/>
> MythTV
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> mythtv-commits@mythtv.org
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>

Does this warrant its own ticket, because I suspect its not really related
to this one that was
originally opened in January?

Regards
--
Brad.