Why is MythTV recording EVERYTHING I watch in Live TV?
MythTV is not your average TV. It's a digital video recorder! When you watch TV, the ability to pause, rewind, and skip commercials is because it is actually recording everything you watch. As an added bonus, when you are watching something and decide you want to keep it, hitting record will just tag the existing recording as a keeper. The LiveTV page has lots more info, but here are the three most FAQs.
But my Harddrive keeps filling up from all these Live TV recordings! How do I stop it from recording?
* Short answer: You can't.
* Long answer: You can't stop it from recording, but you can stop it from filling up your harddrive. MythTV is designed with an autoexpire concept. Every time Myth tries to watch or record something, it first makes sure that it has room for it, and will delete the oldest available recording to make space. You can specify how much free space to leave, but it is recommended to dedicate a partition to Myth recordings and tell it to leave at least one gigabyte free. Live TV recordings by default have a shorter lifespan than normal recordings and a lower priority, so they will be expired before any recordings are.
It didn't used to do this, why did it change?
* It always did. In versions before 0.19, it saved live TV recordings to a separate file (a ring buffer), which stayed within a certain size range. It got complicated when you have more than one tuner and more than one live broadcast being viewed. There was no easy way to transfer from that ring-buffer file into a normal recording, so even though you can pause the TV, there was no way to keep it (and if you paused for long enough, another scheduled recording would come around and wipe out your live TV buffer).
I don't want it to delete things unless I tell it to!
* You have the option when recording a program to have it auto-expire or not, as well as the ability to change that setting on an individual-recording basis. If no programs are set to auto-expire, however, it will run out of space very quickly.