SOLVED: Buffering while playing 4K REMUX through Chromecast

[loldemort]

Hello,

I am running Jellyfin 10.10.5 in a Docker container on Ubuntu 24.10. I am trying to stream a movie through a 4K Chromecast with Google TV that I have plugged into my LG TV.

On Chromecast, the movie will play for about 5 seconds, then stop for about 8, then repeat. I'm using the official Jellyfin Google TV app. The movie plays without issue on the Jellyfin Media Player desktop client and the Android mobile app. 

I have checked the download speed the Chromecast gets by using a browser app and going to fast.com. I'm using Wifi, but this issue is consistent enough that I don't think connection instability would be an issue, but let me know if I could be wrong about that. I consistently get download speeds > 200 mbps. I have also confirmed that the video is being streamed directly without any transcoding.

Attached are metadata for the movie.

Are there other things I can do to try to troubleshoot this?

[TheDreadPirate]

Can you share your main jellyfin log via pastebin?

/config/log/log_20250128.log

If there are ffmpeg logs, share the latest one.

[loldemort]

Can you share your main jellyfin log via pastebin?

/config/log/log_20250128.log


If there are ffmpeg logs, share the latest one.

Trucated the a good chunk from the beginning of it because it was too long, but hopefully this gives you the needed portion
Main Jellyfin Log:
https://pastebin.com/xSthYAau

This is one that was created when I was experimenting with changing the bitrate from the Google TV Jellyfin app. I usually directly stream though
FFMPEG Log:
https://pastebin.com/ytbvDfh2

[TheDreadPirate]

Transcode performance doesn't appear to be an issue. The only thing that makes sense is network performance. Speed test sites are good for measuring max speed bursts, but not great for averages.

How close is the CCwGTV to the router? Is it the farther device from your router? Is the CCwGTV connected to a rear port so that the CCwGTV has to pass through the TV to reach the router?

[loldemort]

It's probably about 15 feet in the same room. Yes, it is on the rear side of the tv and has to pass through it to get to the router

[TheDreadPirate]

Is everything going through Tailscale? Even local devices?

I see a couple instances of what looks like a local IP, but I'm not sure which of your devices that is.

[loldemort]

Yes, everything including local devices go through Tailscale. The local IP activity might have been from when I was trying to play the video with the WebOS Jellyfin app on my tv.

[TheDreadPirate]

Does this same issue happen on the CCwGTV if you go directly to Jellyfin without Tailscale? Is the CCwGTV on the same network as the server?

[loldemort]

Connecting to the server's regular local IP address instead of its Tailscale IP address solved it!!!

I tested the Chromecast both being connected and disconnected from Tailscale (connecting to the server's local IP) and it played flawlessly regardless.

Overall, using Tailscale still seems viable for everything up to compressed Blu-ray rip quality 4K content, which is an awesome option to have on the road.

Appreciate your assistance!