Troubleshooting:Error was encountered while displaying video

From an email by Daniel Kristjansson on Aug 17, 2006

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.