Playback freezing when playing 1080i

I have a weird problem. I'm running LibreELEC 8.2 on a 905W box (AZW W95) with a HDHomerun Connect Quatro, Tvheadend 4.2, and wired Gigabit LAN. The box works fine when watching live TV. I can pause, resume, etc. But when I'm stressing the system (i.e., recording 3 channels while watching live TV on another channel, recording 4 channels while playing a recording, etc.) the picture will freeze (it is actually stuttering between a few frames). The sound continues but it will pause for a second every several seconds. This only happens on 1080i channels. Some more information:

1) If I switch to any 720p channel everything works fine.

2) If I switch back to the 1080i channel that that initiated the problem the same stuttering frames are there and the sound track continues but pauses every few seconds.

3) If I switch to any other 1080i channel I see the same stuttering frames from the channel that initiated the problem and the appropriate sound track plays but pauses every few seconds.

4) If I play a 720p recording everything works fine.

5) If I play a 1080i recording I see the same stuttering frames from the channel that initiated the problem and the sound track plays but pauses every few seconds.

6) If I turn off hardware acceleration all channels will play but with the associated issues of no hardware acceleration.

7) If I turn the hardware acceleration back on the the same stuttering frames and sound pauses happen when I try to perform 1080i playback.

8 ) If I suspend the system and turn it back on the issue is still there.

9) If I reboot the system the problem goes away until the next time I stress the system.

10) Recordings are not effected by this. If the problem occurs when I'm watching a recording in progress, the recording successfully completes and is playable unless I reboot the system.

Are there some settings I should change or is this a hardware problem? Or am I just asking for too much from this box?

Thanks in advance for any input.

My box does seem to run hot. I've seen it as high as 85°C but it normally runs around 75°C - 80°C when making multiple recordings. I'm not quite ready to open up the box yet. There doesn't necessarily seem to be a correlation between heat and the problem. In fact, the box temperature seems to go down once the the problem has occurred. What I have noticed is the the CPU load gets high (bumps 100%) and I experience some buffering prior to the problem occurring. Once the problem occurs the CPU load decreases. And the problem is still there if I stop all recordings and try to play a 1080i source even when the temperature and CPU load drop.

I'll try to see if I have any higher powered adapters laying around but I'm not ready to buy a new one for an experiment.

I changed the Tvheadend timeshift storage location from the default (I assume the SD card that LibreELEC runs on) to my USB 2.0 hard disk that I make the recordings on. This has improved the situation.

I can now be recording 3 sources while timeshifting a fourth without causing a problem. I can also record 4 sources and watch one of the sources while recording without causing a problem. It was only when I was recording 4 sources while playing a recording over my LAN did I experience a problem.

And the problem has improved slightly. A 1080i source plays in slow motion now while the audio continues normally. Then it will buffer, the frame catches up with the audio and then plays in slow motion again. If I change to a different source the same thing happens but it plays the correct source. 720p sources still play fine and I still need to reboot to correct this.

Thanks for your suggestions

I think I've isolated the problem to the Tvheadend Timeshift option.

When I disable timeshifting in Tvheadend everything seems to work OK. I can record 4 programs while watching another recording from from either the attached hard drive or over the LAN form a WD My Cloud. I can skip forward, back, pause, etc while watching the completed recordings or the in-progress recordings.

If I enable timeshifting and set the buffer location to the SD card the problems come back.

If I move the buffer location to my attached hard drive the problem gets a lot better.

If I set the Timeshift Maximum RAM size option to 0 while buffering to the SD card things get even better. The main problem I have is playing a recording over the LAN while recording other programs. The recording is constantly buffering (with very slow progress) and is basically unwatchable. Pausing and skipping live 1080i TV works most of the time but will sometimes freeze after extensive use.

The best work around I have found so far is to set the Maximum RAM size to 0 while buffering to the attached hard drive. I can watch recordings over the LAN without buffering while recording other programs. This also seems to be the most stable option for watching live TV (other than disabling timeshifting) in normal use. One downside is skipping and resuming live TV from pause isn't as "snappy" as when using RAM for the buffer.

Any ideas of what is going on?

Thanks

Dang!

Thanks for letting me know, just wish I knew it was this before I spent so much time. At least I have a reasonable work around until Kodi 18 and Tvh 4.4 is released.

What issues will still remain?

Thanks again