Since september last year (2025) I’m using - if not, experimenting with - TrueNAS Scale, built upon a modest system with an ASRock B550M Pro4 mb, a Ryzen 5 5600GT cpu together with an ASRock Intel A310 gpu. There were 2 main goals for building the server: one was for central datastorage and the other more demanding purpose was a mediaserver that must be reachable from outside my home network.
So I begun by covering all the basics: getting a free domain, a ddns-updater, an nginx proxy manager, an SSL certificate and so on. The learning curve to help me understand about vdev’s, pools, datasets … was steaper than expected and after dealing with several spontaneous reboots and even system crashes I decided to go for Jellyfin as my mediaserver. Once installed and figured out how to mount my libraries and set-up hardware transcoding, I could start populating my drives with my mediafiles. The first tests with streaming all kinds of content whitin my homenetwork, looked promissing. I created a few users and invited them to listen and to watch as concentrated as possible in order to detect and report hick-ups, interruptions … Clients streaming 4K movies over ethernet or even over wifi didn’t report any issues. However when trying to stream the same content over a mobile network caused video to stutter although the bitrate is 11 Mbps where the downloadspeed of the network is 150+ Mbps. Whether movies are played directly or transcoded first, it doesn’t matter …
I did a few tests, like: disabling AdGuard, nginx, even omit the SSL certificate … None of this seem to resolve the stuttering video. However, by accident I turned on VPN service on my mobile while on 5G and there was no stuttering anymore. Another workaround is to lower the quality by decreasing max speed in the clients player.
Can someone please explain what is happening here?
Thanks!
Not sure about the mobile app, but in a browser there is a setting for bitrate (which will cause the jellyfin server to transcode). You can set a lower bitrate and see whether it helps.
Also, there is a “playback info” option (should be present in the app as well). This info can give you a clue. Posting the screenshot also can help.
You’ve already done it. Didn’t notice it, my bad. So, it looks like a network issue.
Some other questions:
Are any other users outside of your network (but not on a mobile network) experiencing the same issues? What about other users on mobile network? Do they have a different carrier?
Did you just forwarded a port to your jellyfin? I mean no VPN needed to access it, right?
Welp, usually there is also a dropped frames count (and some other info). Just to exclude the issue with your smartphone, can you share mobile internet with your laptop (or pc/tv/console) and play the video from the “big” device?
You note your download speed, but what is your upload speed, that is what matters when serving content from your network , outside of it…
If turning on a VPN makes it better, that seems weird, is this your own VPN back to your home network, or some 3rd party VPN and where do you connect to on their side? (Your own country, somewhere else…)
If could be traffic shaping on the mobile network. Not sure about which country OP is in, who their provider is, or what applicable telecom laws are present for them, but it is fairly common to have different ‘tiers’ based on the type of traffic the telecom is picking up.
Before any outrage, some of this is borderline mandatory & good; ie prioritizing emergency services.
It’d also explain why a vpn actually gives better performance.
That’d be my two cents from my experience in wireless operations if this is impacting ONLY watching streams on mobile network while all others are working fine.
Edit; ever wonder why speed tests perform so well compared to everything else?
However when trying to stream the same content over a mobile network caused video to stutter although the bitrate is 11 Mbps where the downloadspeed of the network is 150+ Mbps.
Something that you should be aware of. Your internet speeds are usually not symmetrical. So that 150+ Mbps download speed is irrelevant because for your server to stream to those mobile devices, it uses your upload speed, which is often 10x slower. My ISP, for example, gives me 300 Mbps down, but only a paltry 11 Mbps upstream.
If you’re tunneling over a VPN or something, expect speeds to be slower still due to overhead.
Yes. I connected my laptop to the hotspot of my cellphone with the ame result. The only way to somewhat prevent interruptions, is to lower the quality at client side to 3 Mbps. BTW: my provider gives me 40 Mbps upload.
Testing on another mobile betwork will be something for the next days, but i think it won’t be any better.
I’ll post the results later. Till than, I appreciate your interest and help.
What are the ports of your jellyfin and your VPN? It can be that your carrier limits the bandwidth of connections with certain (usually high-number) ports.
OK. I’m back with some results. Nothing surprising though: stuttering on other mobile networks as well.
When I limit bitrate to 4 Mbps max, transcoding is doing its job and all goes well.
