Stuttering on playback

[rojoreds]

Hello everyone...I am a new user of Linux system and jellyfin.  I am 74 years old and working with Linux and Jellyfin trying to set up a media server.  I pretty familiar with computers overall but am struggling with this media server.  I am usuing the latest version of Ubuntu Desktop.  I have my media library filled with movies and tv shows that are in MKV format.  I am not using docker containers just a headless server.  The media plays fine when I am on the server natively but when I access and try to play media on my desktop or my ipad it is pretty much useless.  The playback constantly buffers.  I am fairly certain is it because the media is transcoding when I want it to direct play but have not been successful in getting it to work and am hoping someone here might be able to educate me on what I might be doing wrong.

My server is as follows: 
CPU is Intel i9-9900k
GPU is GeForce NVIDIA RTX 2080
System Mem is 32gb

I am attaching a screenshot of the playback info when I am attempting to watch a tv show below.  You can see it is transcoding.  I have attempted to set up the transcoding codecs following the jellyfin guide for Nvidia graphics cards but I must be missing something.  Perhaps someone could tell me specifically what settings on the playback settings I should have this system set to that would help very much.  Thanks in advance for any assistance.    

[Rastin]

The transcoding is causing your problem. Do you have hardware transcoding enabled?

Go to:

Dashboard → Playback → Transcoding

Make sure:

Hardware Acceleration:

✔️ Enable hardware acceleration
✔️ Hardware acceleration method: NVIDIA NVENC
✔️ Enable hardware decoding
✔️ Enable hardware encoding

If NVIDIA NVENC does not appear, then drivers are not configured correctly.

[rojoreds]

Thank you for your reply.  I believe I have all that set already.  I am going to try to paste screenshots of my playback settings.

[Rastin]

Whats your bandwidth like your upload and download? Is your server wired or wifi? Are you using jellyfin-FFmpeg or the standard version if the standard you will need to install the jellyfin-FFmpeg.

[rojoreds]

Well to be honest I don't know my actual bandwidth. All my devices go thru my router. The server is wired as is my desktop. The ipad is wireless. As far as what jellyfin I am using I just downloaded the server version right off the website. How do I get the jellyfin-FFmpeg?

[Rastin]

I just look at your screen shot it shows your using the right FFmpeg so don't worry about that. Are you using the web browser to watch or the jellyfin video player. If the browser it may not be able to decode MKV files hence why its transcodeing. use the jellyfin video player and see if this fixes your problem. this wont fix the transcodeing problem but bypass it and let it play direct but if your not using it out side your network it should be fine. if this works but some files wont play try turning off hardware transcodeing.

Install the dedicated Jellyfin apps instead of using a browser.

For Desktop:
Use Jellyfin Media Player (not the browser).

For iPad:
Use the official Jellyfin iOS app from the App Store.

[rojoreds]

Thanks for your reply. I am using the chrome browser on my pc. I checked the jellyfin site for the windows version of jellyfin from github but it has a note indicating they don't recommend using that version. Is there another place to get it or is it actually ok to use it? The ipad is using the jellyfin media player from the app store. Interestingly enough it worked after I first set things up .... watched several tv episodes on it but after a but it started with the same buffering issue that I have on the desktop.

[Rastin]

I'm no expert on jellyfin just been tring to fix my own issue, So i just passed on what i have read so far. I just ran your question through Chat gpt so maybe there something in its answer that will help or someone that knows more about this will be able to help.


With your hardware (i9-9900K + RTX 2080 + 32GB RAM), Jellyfin should absolutely fly. Buffering is almost certainly one of these:

It’s software transcoding instead of using your NVIDIA GPU, or

It’s transcoding when it doesn’t actually need to (client compatibility issue), or

Network bitrate is too high for the client connection.

Let’s go step-by-step and simplify this.

Step 1 — Confirm If GPU Transcoding Is Actually Working

In Jellyfin dashboard:

Dashboard → Playback → Transcoding

Make sure:

✅ Hardware acceleration: NVIDIA NVENC

✅ Enable hardware decoding

✅ Enable hardware encoding

✅ Allow HEVC encoding (if available)

❌ Disable VAAPI (don’t mix with NVIDIA)

Then restart Jellyfin.

Now verify from terminal while something is playing:

Run:

nvidia-smi


If hardware transcoding is working, you should see:

A process called ffmpeg

GPU utilization % above 0

Some memory usage on the GPU

If GPU usage stays at 0%, Jellyfin is not using NVENC and is falling back to CPU software transcoding — which causes buffering.

Step 2 — Why Is It Transcoding At All?

Even with GPU working, ideally you want Direct Play, not transcode.

Common reasons Jellyfin forces transcoding:

1️⃣ Subtitle format

If you're using:

PGS subtitles

VobSub

Image-based subtitles

Jellyfin will transcode video to burn them in.

Test:
Turn subtitles OFF and try playback.

If it suddenly Direct Plays → that’s your issue.

2️⃣ Codec incompatibility (very common with iPads)

iPads often do NOT support:

Some HEVC 10-bit files

Certain high bitrate H.264 levels

DTS audio (very common!)

If your MKV contains:

DTS audio

TrueHD audio

The iPad will force transcoding just for audio — and sometimes video too.

Step 3 — Check What the Playback Info Says

When playing a file:

Click ⚙ Playback Info and look for:

Video: Direct Play or Transcoding?

Audio: Direct Play or Transcoding?

Container: MKV Direct or Transcoding?

Very often it’s actually audio causing the video to transcode.

Step 4 — Your Network Might Be the Real Issue

Are you accessing:

Over local LAN?

Or remotely over internet?

If local:

Make sure client quality is set to:

Settings → Playback → Video Quality
Set to: Original

If set to Auto or 10 Mbps etc, it WILL transcode.

Step 5 — Make Sure NVIDIA Drivers + NVENC Are Installed Properly

On Ubuntu:

Check driver:

nvidia-smi


If that works, good.

Now check ffmpeg has NVENC:

ffmpeg -encoders | grep nvenc


You should see:

h264_nvenc
hevc_nvenc


If not — Jellyfin cannot use GPU encoding.

Step 6 — Critical Jellyfin Settings Checklist

In:

Dashboard → Playback

Transcoding:

Hardware acceleration: NVIDIA NVENC

Enable hardware decoding for:

H264

HEVC

MPEG2

Allow encoding in HEVC if you want

Transcoding thread count: leave blank (auto)

Networking:

Dashboard → Networking

Make sure:

LAN networks include your local subnet (example: 192.168.1.0/24)

If not, Jellyfin might treat LAN clients as remote and limit bitrate.

Step 7 — Quick Test To Identify Root Cause

Try this:

Pick one MKV file

Disable subtitles

Set client quality to Original

Play from a browser on your desktop

Check playback info

Tell me exactly what it says for:

Video

Audio

Container

Bitrate

That will immediately tell us what’s triggering transcode.

Important Question

Are most of your files:

4K HEVC?

1080p H.264?

Using DTS audio?

That matters.

Most Likely Cause (Based on Experience)

With your hardware, the most common causes I see are:

❗ DTS audio forcing transcode

❗ PGS subtitles forcing burn-in

❗ Client quality set below Original

❗ NVENC not actually enabled correctly

[rojoreds]

Thanks for your reply.  I am using the chrome browser on my pc.  I checked the jellyfin site for the windows version of jellyfin from github but it has a note indicating they don't recommend using that version.  Is there another place to get it or is it actually ok to use it?  The ipad is using the jellyfin media player from the app store.  Interestingly enough it worked after I first set things up .... watched several tv episodes on it but after a but it started with the same buffering issue that I have on the desktop.

OK I downloaded the windows version of jellyfin client media player and I get the same results as before so there must be something else going on.  While playing the media I checked the settings and it showed it as direct play but I still get heavy buffering.    I attached a new screenshot showing that.

[rojoreds]

OK...I think I have figured out why this was happening. I set the server up using a wired connection that was via a powerline connection. I can only assume the copper electrical lines could not handle the amount of data. I switched my server to wireless and everything works just fine. I would still like to have used a wired connection but whatever. It works and my wife is happy so that's all that matters right. Thanks to all who worked with me on this problem.