Just to recap ... I have a Motorola digital-cable box (a DCT 2000) that I
am planning to use an IR Blaster to control. I'm currently working on
getting the LIRC parts working, and I expect the mechanics of it will sort
out in time. But I'm facing one conceptual puzzle.
When the Motorola box changes channels, there is a lag of a couple of
seconds between the time the (manual) remote finishes sending the
channel-change instruction and the time the new channel displays. After
that, the Motorola box briefly displays its own OSD with information about
the show selected, much the way Myth itself does. I can adjust how long it
displays this information, with 3 seconds the minimum time, but I cannot
(or at least there is no documented way I can) disable this display
completely. Since the overlay is part of the signal that gets sent to the
v4l capture card, it will appear at the start of every show I record with
Myth. And, of course, I have no way to speed up the actual process of
changing the channel on the Motorola end.
What this means is that I need to get the Motorola box to begin the process
of changing channels somewhere between 15 and 30 seconds before the start
of the show I want to record. How do I accomplish this this using Myth?
With my other capture system (running vcr/avifile through crond), the
solution is to start the process a minute early, change the channel (which
will take a few seconds), wait a few seconds to let the OSD come on and
off, then start recording. All easy to add into the small Perl program I
use fto control the recording process.
But since Myth has no option to begin recording X seconds before the start
of the show, I don't see a way to implement even approximately similar
functionality using Myth. (Since I use ntp to sync the time and know of no
way to insert a 1-minute time zone offset, fudging the system clock is not
a practical workaround ... without ntp, the system clock would be too
drifty to trust for any video start times.)
What do those of you with external channel changers (I surmise that
satellite receivers have a similar "feature") do to work around this
problem? For that matter, what does a TiVo do (if anyone knows) about this
when it is controlling an external channel selector?
This is not quite the question that Calvin asked earlier today and that
Carlos answered with the C program. That thread addresses delays on the PC
side. I'm concerned about delays that are external to the PC, delays that
derive from the normal operation of the Motorola DCT2000.
am planning to use an IR Blaster to control. I'm currently working on
getting the LIRC parts working, and I expect the mechanics of it will sort
out in time. But I'm facing one conceptual puzzle.
When the Motorola box changes channels, there is a lag of a couple of
seconds between the time the (manual) remote finishes sending the
channel-change instruction and the time the new channel displays. After
that, the Motorola box briefly displays its own OSD with information about
the show selected, much the way Myth itself does. I can adjust how long it
displays this information, with 3 seconds the minimum time, but I cannot
(or at least there is no documented way I can) disable this display
completely. Since the overlay is part of the signal that gets sent to the
v4l capture card, it will appear at the start of every show I record with
Myth. And, of course, I have no way to speed up the actual process of
changing the channel on the Motorola end.
What this means is that I need to get the Motorola box to begin the process
of changing channels somewhere between 15 and 30 seconds before the start
of the show I want to record. How do I accomplish this this using Myth?
With my other capture system (running vcr/avifile through crond), the
solution is to start the process a minute early, change the channel (which
will take a few seconds), wait a few seconds to let the OSD come on and
off, then start recording. All easy to add into the small Perl program I
use fto control the recording process.
But since Myth has no option to begin recording X seconds before the start
of the show, I don't see a way to implement even approximately similar
functionality using Myth. (Since I use ntp to sync the time and know of no
way to insert a 1-minute time zone offset, fudging the system clock is not
a practical workaround ... without ntp, the system clock would be too
drifty to trust for any video start times.)
What do those of you with external channel changers (I surmise that
satellite receivers have a similar "feature") do to work around this
problem? For that matter, what does a TiVo do (if anyone knows) about this
when it is controlling an external channel selector?
This is not quite the question that Calvin asked earlier today and that
Carlos answered with the C program. That thread addresses delays on the PC
side. I'm concerned about delays that are external to the PC, delays that
derive from the normal operation of the Motorola DCT2000.