If not, is there another way to make analog audio via USB work?
Don't forget to activate analog audio at the LE audio settings ("HDMI + Analog" activated).
Check the presence of analog audio on the headphone jack of RPi.
If it doesn't helps, check analog volume.
But I give it a try and let you know if it worked.
It worked for me. 
Is it a matter of tweaking settings in LE or Kodi? I'd prefer to do this from LE if possible rather than having RetroArch terminate Kodi.
I don't know the implementations, too, but I think there are no helpful tweaks. The LE game engine is a young feature, and probably not optimized yet.
I don't know your hardware. For my Raspberry Pi I usually plug the MicroSD card off, and edit stuff on my Linux PC.
Here are instructions how to edit config.txt otherwise.
Yes, it is. Add this line to /libreelec/config.txt :
disable_splash=1Is Wetek Play 1 still supported by LibreElec?
Not anymore. Read here.
I didn't know that TR is an OpenGL game. Is there a list somewhere of which PSx games are OpenGL and which ones aren't?
I've never seen a ROM site, which has that much details. If there is one, I'm not sure whether it's allowed to give a link.
Reproduce the error, and then post a link to the log file please. It's usually telling the story.
IIRC, LE RetroArch isn't GL accelerated yet, all the cores are software mode.
Good point. frankvw was talking about Tombraider, which is an OpenGL game. Maybe only the non-GL PS1 games run smooth on LE.
I would try dual boot with a gaming OS as workaround.
True statement. Support means updates and answering questions. Very important, and it means long-term costs for companies.
Since the release of RPi 4B we have a low-cost 4K streaming box, which runs LibreELEC, and has free support. 
It's hard for streaming box companies! Even China can't concurrent with it. That's why this forum is currently under attack from there.
That said, Mario77 has it running fine on his RPi2 so there must be something wrong with my install or settings.
Do you use RetroArch as suggested by Mario77? Or maybe the ROM's are wrong (not optimized for the emu).
PS1 games are known to be very demanding on an RPi. Not sure if they run smooth on any RPi OS.
Multi-Threading is the best way to get max. performance, but the PS1 emu has to be made for this (can be a serious task).
See what pure gaming OS'es can do, and then compare with the LE performance.
If you see room for improvement after this, make it a feature request.
Because Serviio supports:
- Movie thumbnails (Kodi - not supported or not working; I've seen complaints in forums but no solution)
- Video playback resume (not supported in Kodi; scrolling with TV remote to a middle of the 2hrs movie - nightmare; and you have to remember where you stopped)
- Sorting automatically my TV series into series, seasons, last watched episode etc. (not so good in Kodi)
Good ideas for feature requests. Go for it!
To install Java for this would be kind of an overkill.
So is it possible to install Java, FFmpeg, libRTMP, libASS, libx264 and libmp3lame to LibreELEC?
No.
Tell us what you want to do, and maybe a solution beyond Serviio already exists.
Sorry if I didn't explain it very well. Somehow I pressed a button on my Verizon FIOS remote that enabled the Kodi mute function. I had not mapped any keys on the remote to be a mute button. I tried several buttons, but it didn't un-mute. Had to attach a keyboard to get it to un-mute.
You can do two things with my method:
a) find the already defined and undesired mute button, and disable it by overwriting it with a "noop" action
b) keep the undesired mute function alive, and use a color button to un-mute (copy my example, and press yellow)
I'm using an RPi 3B+, too. Yesterday I went back to LE version 9.0.2, because the system went into safe mode a couple of times with LE 9.1.002.
I suggest to use the stable version 9.0.2. If you still get issues, post the log as mentioned by Iridium. Your current link doesn't works.
Sir, you could define a mute / un-mute button on your remote control (full keymap list).
Here is an /storage/.kodi/userdata/keymaps/remote.xml example:
<keymap>
<global>
<remote>
<red>VolumeDown</red>
<green>VolumeUp</green>
<yellow>Mute</yellow>
<blue>ContextMenu</blue>
</remote>
</global>
</keymap>I don't think it's an LE problem, because screen calibration has no effect. Modern TV's often have picture optimization modes, and some modes slightly change the filling of the screen. Play around with your TV settings.