Backend stops LiveTV recording to record a scheduled program, causing frontend LiveTV playback to fail

[Kenni Lund [kenni a kelu dot dk]]

Today while watching Live TV, the picture suddently stalled followed by an exit to the main menu with "Video frame buffering failed too many times". According to the logs, the backend stopped the Live TV recording in order to start a scheduled recording, but no graphical notification were given in the frontend - the frontend playback was just disconnected.

Additionally, two virtual tuners were available at the right multiplex, so no interruption should have been needed at all.

Background info:

Tuner1: HDHR1, virtual tuner 1
Tuner2: HDHR1, virtual tuner 2
Tuner3: HDHR1, virtual tuner 3

Tuner4: HDHR2, virtual tuner 1
Tuner5: HDHR2, virtual tuner 2
Tuner6: HDHR2, virtual tuner 3

Both physical tuners are connected to the same source.

Just before the incident, the status of the tuners were the following:

Tuner1: Free (but presumably locked to mplexid 19)
Tuner2: Viewing Live TV on mplexid 19.
Tuner3: Free (but presumably locked to mplexid 19)
 
Tuner4: Recording "Two and a half men" (20:00-20:30 = 19:57-20:33) on mplexid 7.
Tuner5: Free (but presumably locked to mplexid 7).
Tuner6: Free (but presumably locked to mplexid 7).

At 20:27 in the backend log, the scheduler wants to record the next (back-to-back) showing of "Two and a half men" (20:30-21:00 = 20:27-21:03) on the same channel/multiplex as Tuner4 is already recording on. Instead of using Tuner5 or Tuner6, it stops Tuner2 and uses Tuner1 to start the recording. At this point the frontend ringbuffer becomes empty and Live TV fails due to an empty buffer.

Perhaps related: When I starting the LiveTV session at 19:39:51 (backend log time), it seemed like the backend went into some inconsistent state - the frontend only showed a black screen with no sound instead of the Live TV recording. At 19:40:07, I went into the Program Guide and selected the SAME CHANNEL as it was already supposed to be on, which "fixed" the LiveTV playback. This was the LiveTV session which failed ~50 minutes later.

[Kenni Lund [kenni a kelu dot dk]]

I had the LiveTV failure (Video frame buffering failed) twice the other day - no new recordings were started at the time of the failure, so it seems like the initial report was a coincidence. I'll be upgrading the production systems to pre0.26 today and will create a new ticket if/when I hit the issue with 0.26.