Tvheadend

Tvheadend has a DVR/PVR function. At the moment the recording management is extreemly basis. This page will describe possible options for improving this and the design decisions that need to made to implement these improvements

== Initial thoughts ==

Here are some initial thoughts that we might need to find answer to;

 * should you be able to delete a recording from the OS and how should the DVR handle that

 * how do we keep tvheadend from filling up your hdd

 * should you need to specify a certain "savety" disc space

 * what if an other process is filling up the hdd .. should that mean we keep deleting recordings ?

 * when do we "expire"/delete recordings? when a new recordign starts make enough room to completly record it?

 * what is there are 3 or 4 concurent recordings? how do we know we have enought space

 * do we keep track of the estimated bit-rates of the various channels to beter figure out the needed space for a recording? (difference between SH and HD etc)

 * take the duration of a recording/size of recording and use that as a measure (average over time??)

 * estimaed recording lenght * estimated bit-rate to determine how much we need to clear

 * do we need to keep track of the amount of free-space during a recording and possible delete more old recordings when needed

 * do we need to test the write speed of the filesystem that is used to store recordings? in order to prevent too many concurrent recordings?

 * do we want to support multiple storage locations?

 * or do we say: if you have a need to record a large number of concurent recordings .. make sure your filesystem is up to it

 * do we want to have support linking multiple instances of tvheadend to schedule recordings across multiple backends?

 *  how about conflict handling? I have 2 capture cards but I want to record from 3 transportstreams how to manage that ?

 * we also need to "re-arrange" all previous scheduled recordings if a new request comes in

 *  do we directly link a recording schedule already to a capture card? so that we can keep track and use that when working out possible conflicts?

 *  what if there are multiple clients making a schedule recording request. Do we keep one "on hold" untill the first one is completed and scheduled?

 * who solves the conflict? can everybody make that decision? should that be a "user rights" option?

 * how do we inform the original requested user if his or her recording has been removed in order solve a conflict?

== basic guidelines ==

in order to keep things focused we need to have a set number of basic guidelines for this:

 * Tvheadend will only use one location for storing recordings. 

 * Tvheadend will make as many concurent recordings as requested. If the filesystem can not keep up, you need to fix that on the linux side.

 * Tvheadend will clear enough room to store the expected recording size at the start of the recording. It will take into account already running recordings.

 * Tvheadend will determine free disc space only on the recording location filesystem.

 * Tvheadend will determine expected recording size based on previous recordings (of that service, or total average when no recordings are known)

 * Tvheadend will not use a database to store information about recordings.

 * Tvheadend recordings should contain enough metadata to show meaningfull information via the webGUI.

 * Tvheadend can be used to manually delete recordings via the webGUI

 * Tvheadend will remove recordings from the webGUI when delete from the commandline/other tools

 * Tvheadend will remove recording when moved away from the recoring location.