Posts by vobs

Quote from popcornmix

I'm talking about the ffmpeg based MVC decoder (which is a new thing). The Zidoo is using a completely different (likely hardware) decoder.
I don't think it's possible for it to be in the actual hdmi output path (it has no knowledge of a frame from 10 frames in the future).

It's going wrong either in the decoder, or somewhere in the render path of kodi. But that wouldn't be affected by the type of display/projector used.

If you add this advancedsettings.xml file:

Code

<advancedsettings>
 <video>
   <stereoscopicpreferframepacking>false</stereoscopicpreferframepacking>
 </video>
</advancedsettings>

it will disable framepacking and output as half-sbs (or half-tab). Is that any different?

May be useful to disable 3d mode and look at the two halves - do both have a consistent glitch or just one eye?

I created an advancedsettings.xml file in plain text format and placed it in the /userdata folder, but it still outputted 3D in frame packing format. However: Wouldn't the result be the same if I disabled stereoscopic mode in Kodi playback, so that it outputs a 2D image with both the left and right parts side by side? If yes: This gives me a steady smooth movement without glitches, as long as I don't set the projector manually into SBS 3D mode. As soon as I do this, the glitches occur again. I know this sounds weird ¯\_(ツ)_/¯

Quote from popcornmix

That feels like an MVC decode error. I'd need to get hold of a sample file that shows this error.

Can you check if any MVC samples from https://kodi.wiki/view/Samples show this sort of issue?

If so, do they all? If not, I'd need to get a short sample of one of your files.

I would bet it's not a MVC decode error, since:
1. the same MVC files do play perfectly on the Zidoos I have (Z9X Pro and Z20 Pro)
2. the glitches occur with every MVC file and also when playing FSBS 3D files. Basically, anything in 3D. And sometimes even when playback is paused. It basically happens when Kodi switches into 3D mode

Quote from popcornmix

If you step frame by frame in youtube around 41s, I think you are getting a frame from the future (about 10 frames in advance).

Precisely! That's the behaviour in every case. Sometimes it's more obvious, and sometimes it's so short that it's barely noticeable.

Quote from vobs

(...)

Since I had some difficulty getting the PI5 to show up on the projector at all, I thought the issue might be specific to older HDMI 1.4a FHD 3D projectors.

ps: ChatGPT told me that a "HDFury Communicator Dr. HDMI 4K" may solve this issue - should give it a try?

Quote from popcornmix

A longer video would be useful. 1s is too short (and really annoying to watch in YouTube where it keeps switching to another video…)

I’m suspecting that’s more like a decode error than a 3d error.
Does the glitch occur at the same timestamp every video?

Have you tried multiple videos?

A sample would be useful. e.g. cut a 1 minute chunk, confirm your can see the issue with it and then upload to google drive (or similar).

You're right, the short video was initially meant for a direct forum upload, I apologise for the inconvenience. I made another sample for YT which is a bit longer: https://www.youtube.com/watch?v=j8CEo5qYYow -> Here the first glitch occurs at 0:09, a second at 0:32 and a larger third one at 0:41. (Sorry for the poor quality, the shaky setup in my workspace and the loss of quality due to the YouTube upload. I can upload it to a file host later if needed.)

These glitches occur randomly, not at the same timestamps. In most cases, the first one occurs after 7–10 seconds, and the next one maybe after 30–60 seconds. But they never occur at fixed intervals, and they never disappear completely. Sometimes, as in the very short first YT video shown, they even occur while playback is paused. As soon as 3D is deactivated, they disappear. I don't experience these issues with a Zidoo connected to the same HDMI port on the projector. I also disabled the projector's FI, but it made no difference.

Since I had some difficulty getting the PI5 to show up on the projector at all, I thought the issue might be specific to older HDMI 1.4a FHD 3D projectors.

Quote from popcornmix

Might need a better description to understand.

Is it a frame drop/repeat? (although they are normally only visible in scenes with movement, like panning)

Or is a lateral movement (like a frame shifts up/down/left/right occasionally)?

Does it only apply to 3D/MVC? If you choose watch as 2D on a 3D/MVC file do you still see it?

Thanks. First, I must correct myself: it's not just about higher bitrates; it's about the 3D mode in general.

The jutter is more like a lateral movement. It occurs in every situation where 3D is activated (frame packing?). Even when paused! See: https://youtu.be/MGxT68APm8U. Sometimes it plays fine for 30 to 60 seconds without a jutter.

Very strange is that these errors are also present when I disable the Stereoscopic 3D mode in Kodi (so that the film plays in 1080p side-by-side mode) and manually put my projector into SBS 3D mode (with the resulting loss in resolution).

I literally can only play 2D movies without those errors. My projector is a unit from the good old days with 144 Hz triple flash 3D (SIM2 Nero 3 Plus). I think the current version of LibreElec on the Pi5 does not yet work with older HDMI 1.4a 3D projectors.

Quote from popcornmix

Yes, MVC is pushing Pi4. You could try overclocking (the arm) but it may not be enough.

I think Pi5 will be fine with these files.

Sourced a Pi5 and tried it again. The MVC stuttering has basically gone. But there is something else: not exactly a stuttering, but here and there a slight shift in the image (I can't describe it any better; it's close to a very short stuttering, only happens once every 30 to 60 seconds. And only noticeable in scenes with little to no movement.

I tried your Pi4 build it with a spare Raspberry Pi 4B 8GB and basically everything worked. Compressed FSBS files (3840x1080) were being processed on the fly and sent as frame-packed. However, as soon as I tried larger 3D MVC rips with higher bitrates of about 42–48 Mb/s, there was severe stuttering during playback. I switched from SMB to NFS and tried various tweaks in Kodi and LibreELEC, but nothing helped. Eventually, I gave up. I think the RP4's hardware is not powerful enough. Should I try again with an RP5?