Proposal:

By default when playing back tv recordings mediaportal will automatically start playback at the end of the pre-recorded buffer. If comskip chapter markers exist then use the comskip chapters to decide where to start playback.
 
//forum.team-mediaportal.com/threads/idea-skip-to-start-of-tv-recording-prebuffer.119242/

Implementation:

TV-Server:
TV-Server will create 2 additional xml entries that store prerecord + postrecord value for each recording

Mediaportal Configuration:

[X] On playback use pre-record buffer or chapter marker to skip the start of tv recordings
 
^ Enabled by default, only visible in advanced mode, hidden in standard mode. 
 

Mediaportal Client:

 
On playback of tv-recording do the following

1. If no pre-record value in xml then start playback at 00:00
2. If no comskip chapter file then start playback at Pre-Record Value
3. If comskip file is present and pre-record value is within X minutes of any comskip chapters then start playback at first chapter marker that is within X minutes of pre-record value
4. Else start playback at pre-record value

I think the ideal value for X would be -3 minutes to + 1.5 minutes