UHD remux movie stuttering playback

Hi there.

I’m trying to watch a UHD remux movie on a NAS (rp3 with an external HDD shared via NFS) with my Vero 4k, but I’m having some stuttering issues. Every minute or I lose sound and the movie plays slower for a few seconds (subtitles still going on as it should) and than it resumes playing normally.

I was afraid I would have this problem, since my whole network is 100 Mbps, but since the movie is around 60 Mbps (61.6 GB, 02h16) I thought it could work.

I’ve run iperf between the Vero 4K and my NAS and got 94+ Mbps, which is 50+% more than the movie bitrate.

Am I missing something? How can I test the movie transfer speed, and/or check the reason for the stuttering?

Have you tried copying the file to the Vero to test? I really don’t think the RPi is powerful enough to transfer the data fast enough for the stream to be smooth.

Transfering the file right now through network to a uSD on the Vero 4K to test. Transfer speed of 8.5 MB/s, according to Kodi’s interface, which should be enough for a smooth play. Will report when I try playing from the uSD.

That’s touch and go.
I’d test playing the file from the eMMC

Hmm a decent quality 1080p file can need up to 5 MB/s so that might be pushing the limits depending on the file?

OK, copied to the uSD card in little less than 2 hours. Since the movie is 02h14, it was faster by just a little margin. The movie is playing fine now (at least the first minutes), both from uSD card and the NFS share.

Will try to improve the NFS share performance on the rpi3, but I guess it should be better to move my external HDD to the Vero 4K (as I originally planned in case my network wasn’t fast enough). I just don’t know worried how the Vero 4K would behave as my NAS, even though I don’t put much stress on it.

I think it is the physical throughput of data that the RPi struggles with. Can’t you try plugging the external HD straight into the Vero?

I occasionally will, but for now I’ll try a different approach. I’ve been searching and I think I can have an improvement using kernel mounted NFS folders instead of mounting directly on Kodi. Since it’s a simpler modification, I’ll try that and report the results.

If even after this change I have no improvement, than I’ll move the HDD to the Vero 4k and it will be my file server.

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Yes, it seems it really did the trick. Followed this guide and transfer rate in the file manager in Kodi’s system menu increased from 8.7 MB/s to 11.7 MB/s. Movies that were stuttering now are playing just fine - at least the first minutes, where previously they would have hanged for at least 5 times. Just one movie hanged, but it was kinda expected, since it has a medium 86 Mbps bitrate. If I want to play that, I’ll need a local copy.

Now up to change the locations of my library’s folders, and mount the folder on my other Kodi box. Just hope there will be no problem with the MySQL database.


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@Tom_Doyle I can’t stop being amazed by all Kodi can do. Did the trick amazingly well and simple.