Video "playback mode" oddities

I received my Vero V a few days ago and have been setting it up to be as similar as possible to my circa-2015 i3-based LibreELEC/Kodi instance (but with the ability to play video formats that leave my old Kodi instance in the cold). It’s still Kodi with the same skin and same add-ons, so it’s largely identical… but there are some video playback differences that I simply don’t know if they should be expected (e.g., the difference between a dedicated SoC and a generic x86 cpu) or if it’s a problem.

Setup:
OSMC Vero V
Kodi: up-to-date
Skin: Embruary
Add-on: Emby for Kodi Next-Gen
AVR: Denon X6200W
Projector: Panasonic HD
Testing Videos: All 720p or 1080p H264

To preface, there does appear to be a distinct difference between “playback” and UI, as in there seems to be a defined mode switch between the Kodi interface video feed and a playback video feed.

The first oddity is that there is a persistent delay of maybe 3 or 4 seconds between pressing “play” on a video file and actually seeing the video but a second or two less of an audio delay. That is, when pressing “play”, the screen goes entirely black. Two seconds in, the audio starts playing to the still-black screen, and then a second or two after that the actual video becomes visible. Play/Pause after that has no visible delay… just when switching from the UI to “playback” mode.

The second oddity is that a Pause doesn’t always fully pause the video and that’s noted by my Home Assistant integration. Specifically, I am watching a video and press Pause (either via the remote or via the OSD). The video pauses and HA is instantly updated with a “vero Changed to Paused”… but most (not all) of the time, after two or three seconds I’ll see the video advanced by a frame or two (like a video stutter) and HA will be informed that “vero Changed to Playing”. Other than the frame-stutter, it is not playing, but since Kodi doesn’t send another “paused” message, HA stays in “playing” mode.

And finally, pressing Stop on a video (remote or OSD) stops the video and the screen goes black. Most (but not all) of the time, it will successfully transition back to the Kodi screen with maybe only a second or so of delay… but occasionally, it will remain black, like it never exited the playback mode. The only way I’ve found to “fix” those cases is to login via VNC or the web interface and force it to start playing a video. That un-blanks the screen and afterwards Stop has always worked (since it does work most of the time).

Let me know if any of this behavior is just an expected behavior of an SoC-based Kodi solution (with a distinct “playback” mode) or, if it absolutely shouldn’t be happening, what debugging next steps would help quickly find the source.

I suspect with the i3 you are used to the video output always being in the same mode. With Vero, it’s recommended to engage Adjust display refresh rate in the Player->Videos settings which defaults to On start/stop. Now your projector is changing output mode when you start or stop a video. Projectors are notoriously slow at changing mode, for reasons I’ve never seen explained. It seems your AVR is receiving audio before the PJ has changed mode.

Are you saying the audio and video are not in sync when a video starts?

When you pause, there is no mode change (unless you set Adjust display refreshrate to Always) so that’s expected behaviour.

You can minimise the effect by choosing a mode for the GUI that’s the same as most of what you are watching - maybe 1080p24Hz to match your typical Blu-Ray. Or you can turn off refreshrate switching altogether but that may affect smoothness of playback (probably OK if you are not into 4k HDR videos.)

I don’t think anyone has reported issues with Home Assistant before. That stutter on pause is something I’ve seen before but it’s not an issue when using the OSMC remote. We would need some debug logs to invetigate that.

Blank screen on stop is not expected - especially not for SDR video. Again I suspect the slowness of PJ mode changing to be involved. You should not get it if there’s no mode change, ie with either of the suggestions above.

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Yes, that’s a known issue. I already have a fix for it but that needs some more testing before it will be released.

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Thank you! Yes, that’s exactly it. My original Kodi instance had “Adjust display refresh rate” to “Off” since day-one and so I never even knew it was an option.

I turned my Vero’s option to “Off” and it now works exactly like it used to.

I will experiment with that option now that I know it exists, though. Maybe set the UI to 1080p23.976Hz since that’s the majority of my videos now and keep it Off until I get my new projector (Titan Noir Max!) and start watching 4K content. Or switch it to “On Start” if I’m watching a bunch of videos in a row with the same framerate…

No, it just took longer for the video to show up than the audio, likely since this is an older projector.

I did notice that the UI sounds almost never work, but that’s an entirely different issue and maybe not even worth fixing.

Again, thank you!!