I was recording a football game last night, and I waited three hours to start the recording so I can skip commercials. The recording had another hour until it was complete. The Plex app on the Shield asked me if I want to watch from the beginning (~200 minutes before) or live so I chose the first. Well the game started from about 2 hours in so NOT beginning of the recording and not live either. It could not let me rewind any further either. It did let me fast forward though. When the recording was complete, it did start from the very beginning during playback. Anybody else experience this?
I saw a similar result Saturday evening with Live PD when I tried to go back to watching it after my Roku rebooted itself. As far as a I can tell Plex only keeps the last 90 minutes of segments from the tuner while recording and it seems as if when you ask to restart an in progress show it uses that buffer rather than playing the partial recording from the grab directory.
I believe this buffer was kept in it’s entirety until the last user of the session released it but as of 1.9.7 they added pruning:
NEW:
(Transcoder) Support pruning old segments to reduce disk usage in DASH and HTTP transcodes (#7484)
(Web) Updated Plex Web to 3.26.2
Doing so makes a fair bit of sense in terms of saving storage but it means that currently it’s impossible to look back more than 90 minutes into in progress recording. If allowing us to restart an in progress show at any point is intended functionality they’ll need to either tweak the pruning to preserve the buffer until the current show ends or persuade the transcoder to work sanely with a steadily growing file so Plex can play the copy from the grab directory. And in the latter case they’d have to deal with the recording being changed by post processing ( user or Plex’s commercial skip) and then being moved.
@pholan good info thanks! I have always advocated for Plex to create the file in the library (so it appears there BEFORE it is done recording) so you can watch however much of the file is there. But I am sure that, based on Plex architecture, that might interfere with lots of other aspects of the system.
Anyway, is there someone from Plex who can confirm this is a limitation? That way I will start watching in-flight recordings at about the 90 mins mark 
Kosta
I am seeing the same thing using my NVIDIA Shield TV player. When asked if I want to start to watch from the beginning, let’s say for example, 110 minute into an on-going 120 minute recording, PLEX has a 90 minute limit built in. Only once the recording is complete, I can start from the very beginning of the recording.
thanks @leguelp. I wonder why they do that as it does not seem like it should work this way. At the very least, the plex client should be up front about it so you know what is about to happen. Maybe @kinoCharlino knows more???
Assumption: Maybe it won’t allow you to touch or read from the grab folder as it doesn’t want any interference when it goes to post process commercial removal?
Maybe it keeps the buffer file for live view, while maintaining the working copy for uninterrupted end tasks?
I hope that this 90 min limit (to start to watch from the beginning a recording while it’s still being recorded) would be either bumped up, user controlled, or removed all together.
@cayars is this a documented limitation (you can only have so much live tv buffer available?) MCE also had a max livetv buffer (configurable via regedit) but if you were actually recording the show, you had the whole ‘so far’ recorded buffer fully available to you. It is fine if it is a limitation but good to know that what we are seeing is expected.
I don’t know if it’s posted anywhere but it’s no secret and it’s easy to discover. To the best of my knowledge this isn’t adjustable but I too wish it was as it’s often far to short for sports events.
@cayars thanks for chiming in. It’d be good if Plex documented this in the ‘limitations’ section.
