[mythtv-users] Recording from STB that requests channel access pins

[Martin Bene]

Hi,

Running MythTV 0.27; I'm recording some channels via sat box (with subscription card, so I can't use dvb-s card like for FTA channels) controlled via IR transmitter. Depending on time of day and rating of a program, the box sometimes requires a 4-digit access code (meant to protect kids from inappropriate content).

* The protection system can not be turned off/disabled
* The request for the pin is linked to the program, not the channel.
* Start/end times are not too reliable, so starting a recording a couple of minutes before the official start time is often required to ensure complete recordings.
* I've put the pin into the channel change script, so if a pin is requested when changing channels, all is fine.

There is however a nasty problem:
when a recording starts, the current content can be unrestricted, so no access pin is requested. There is also no way to "preemptively" enter the PIN at this time. A couple of minutes later the actual program to be recorded starts and the box pops up the "please enter your pin" screen ==> recording of pin screen instead of program.

So, what would be required to make this work would be to regularly (say, every 15 seconds or so) grab the latest frame and compare it to the "please enter pin" image [there's also a running clock/date on that screen, so it won't be a 100% match]. The actual comparsing could be don using imagemagick for example. If a match is found, send the pin via lirc/irsend.

Is there any infrastructure within myth I could harness to implement something like this, or does this already exist? 
There's a slight similarity to commercial flagging as that can also run concurrently to the recoding and analyze the video is at becomes available, so a new "commercial detection method" might be a way to implement this.

Any ideas on how to best hook such a function into MythTV would be appreciated!

Thanks, Martin
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