Stuttering playback without Transcoding TrueNAS > ATV

[vidkun 13]

I have a brand new TrueNAS build running Emby server that I'm having issues with playback stuttering even though it's Direct Play and no transcoding. Initially, I thought it was limited to files with high bitrates similar the guy reporting in the thread below. Was even seeing ffmpeg pegging a core at 100% despite reports of no transcoding.

 

However, my kids just had the issue this morning with a much lower bitrate movie. This time CPU usage is minimal. TrueNAS UI reporting 3% utilization and top showing nearly nothing going on.

So now I'm even more confused. I've been using Plex then Jellyfin for the longest time but trying to migrate to Emby so that I can get the family off of Plex. This is not helping the move though. 

So detail dump...

Brand new TrueNAS build:
Intel Core Ultra 7 265k
Asus Pro WS W880-ACE SE
64GB ECC RAM
Media pool is a single, 10 drive RAIDZ2 with a 1TB NVME L2ARC

Emby transcode and cache dirs are on a separate dedicated 1TB NVME drive

Emby runs in a docker container with the media directories directly mounted to the container as volumes (no SMB or NFS mounts). 

The NAS has dual 10GbE NICs in a LACP LAGG on Unifi Pro XG 10 POE switch. 

Client is official Emby app on AppleTV 4k over WiFi 5 5GHz via Unifi U6 LR AP. Client and server are on same VLAN.

Logs attached below. Any ideas where to start troubleshooting this further? Or any ideas what could be the issue here?

hardware_detection-63910745576.txt embyserver.txt

[vidkun 13]

Well still too soon to tell definitively, but so far it's looking like using Infuse pointed at Emby server is playing files just fine. Maybe it's just the official emby app that doesn't work well? Don't suppose there's a way to get logs from the client app?

[Luke 42359]

Hi, the Emby Apple TV app has option to switch between two different embedded players. How do you have that configured?

[vidkun 13]

21 hours ago, Luke said:

Hi, the Emby Apple TV app has option to switch between two different embedded players. How do you have that configured?

Originally it was set to 'auto', but currently set to 'mpv'

[Luke 42359]

Can you try setting it back to auto?

[vidkun 13]

Sure. To clarify, it was defaulted to auto when I initially encountered the issue. While trying to troubleshoot the issue, I switched it to mpv which did not resolve the issue.

But yeah, I'll swap it back.

[vidkun 13]

Well last night was the first chance I got to sit down and watch something since changing the player back to auto. This time it did not stutter, but it would play about 30-45 minutes of the movie and then freeze completely. I couldn't pause it or get the player controls to come up or anything. The only thing I could do is hit the back button, but instead of it exiting out of the video back to the movie details screen, it would return to the AppleTV home screen as if the app had crashed. Happened twice trying to get through the movie. 

Of course, going back into Emby app > the movie > and resume started the movie right up instantly where it had frozen then played for another 40-50 minutes before freezing again.

[vidkun 13]

Another data point. Today I tried watching a movie on my laptop through the webUI to see if it played fine and hopefully narrow this down to the Apple TV app. However, it failed miserably. Stuttering immediately upon start. This time at least, it was transcoding audio rather than straight direct play across the board. But still, stuttered a few times immediately, then played about 3 or 4 minutes before starting to stutter real bad to point of entirely unwatchable.

So for another test, I decided to try watching the same exact movie via Jellyfin. Again still in the web UI. Movie file and Jellyfin instance are all on the same server as the Emby server. Not a single stutter at any point. Played straight through perfectly fine despite also transcoding the audio.

Both Emby and Jellyfin are configured for hardware transcoding using the same NVME drive for transcoding and cache paths.

Any ideas how to troubleshoot any potential configuration issues that could be causing this on the Emby side? 

[vidkun 13]

As mentioned, I also have Plex configured on this same hardware and pointed at the same media, etc. The kids were able to watch a couple movies the other day straight through without any stuttering, stopping, or crashing issues via Plex (using official Plex client on Apple TV) like I'm encountering with Emby.

So to recap: I have three media server platforms - Emby, Jellyfin, and Plex. All three are configured essentially the same. Installed in containers on the same server, using the same NVME drive for cache and transcode directories, reading from the same media folders and files which are configured using read-only bind mounts across the board. Emby has issues but the other two do not.

The only other thing I can think of to test next is enabling debug logs and testing more videos. 

[guunter 50]

Are you using QSV or VAAPI for your transcoding? I had issues with using QSV on the official emby docker and switching to VAAPi helped. I have since switched to Linuxserver.io image and can use QSV.

If you're using subtitles turn off subtitle extraction on the fly. Install the Diagnostic plugin and then go to subtitle options and turn on Burn in subtitles so it acts like how Plex uses subtitles.

I guess these are more just anecdotal tips then something that fixes your issues since it's direct play. Infuse is great cause it direct plays everything.

[vidkun 13]

On 4/19/2026 at 12:59 PM, guunter said:

Are you using QSV or VAAPI for your transcoding? I had issues with using QSV on the official emby docker and switching to VAAPi helped. I have since switched to Linuxserver.io image and can use QSV.

If you're using subtitles turn off subtitle extraction on the fly. Install the Diagnostic plugin and then go to subtitle options and turn on Burn in subtitles so it acts like how Plex uses subtitles.

I guess these are more just anecdotal tips then something that fixes your issues since it's direct play. Infuse is great cause it direct plays everything.

Thanks. I am using QSV, but again these are files that are reporting that they're direct playing completely. So not sure that would play a part. 

I did turn off the subtitle extraction on the fly, but no luck.

Also, you did give me an idea so I tried swapping out the official image for the Lsio image hoping that would make a difference, but unfortunately same issue.

The most consistent behavior on these is that it will play an episode for about 30-40 minutes (pretty consistently this amount) straight through and then just freeze up. I back out of the episode and try to resume it, but it just has a spinning wheel trying to start it. Hopping out of emby client and trying to resume the same episode via Infuse (against emby server) fires up instantly without issue.

[guunter 50]

13 hours ago, vidkun said:

Thanks. I am using QSV, but again these are files that are reporting that they're direct playing completely. So not sure that would play a part. 

I did turn off the subtitle extraction on the fly, but no luck.

Also, you did give me an idea so I tried swapping out the official image for the Lsio image hoping that would make a difference, but unfortunately same issue.

The most consistent behavior on these is that it will play an episode for about 30-40 minutes (pretty consistently this amount) straight through and then just freeze up. I back out of the episode and try to resume it, but it just has a spinning wheel trying to start it. Hopping out of emby client and trying to resume the same episode via Infuse (against emby server) fires up instantly without issue.

As a test have you tried watching a video and transcoding it?

[Luke 42359]

@vidkun?

[vidkun 13]

I have not yet tested a video and intentionally transcoding it yet. I will do so.

Though, I have tested the official Roku app and it appears to be working fine. I've watched a couple episodes in it and the wife used it all weekend while I was out of town without any issues. So, I'm starting to think my issue with the browser that time may have been unrelated and it's just an issue with the Apple TV app. 

I'll try the transcoding test via the Apple TV app and see if any improvement.

@LukeWere you asking about guunter's question or were you following up on something else I may have missed?

[vidkun 13]

Alright, I have a single test of forced transcode test and it worked. Not sure why, but it did. 

I was able to watch one episode forced transcoding to a lower bitrate 4k (from higher 4k) and it played all the way through without issue on the Apple TV app. 

I will continue to test this more to see if it continues to work without issue. If so, then I'll test again without the forced transcode of an episode that previously worked with transcoding and see how that goes.

But that still begs the question: why would it work WITH transcoding, but not without? And why limited to the Apple TV official app when Infuse works fine on same ATV from emby (as well as Plex and Jellyfin)?

[visproduction 351]

4K media from what source?  Blu-ray disc media is quite different from 4K, optimized for streaming.  I believe the metadata optimization is also different and if the media has not been transcoded to work best with streaming it will probably have problems playing back on all systems.  Why not test prepared 4K streaming demo videos instead?  Otherwise, you will never know if the file is causing the issues and you are looking for answers from some code issue, when it is not the cause of the stuttering.  Delivering content to clients in 4K for blu-ray masters, blu-ray disc files and 4K streaming are all different files.

https://duckduckgo.com/?q=4K+optimized+for+blu-ray+playback+vs.+streaming&ia=web
https://duckduckgo.com/?q=sample+4K+test+video+streaming&ia=web

[vidkun 13]

29 minutes ago, visproduction said:

4K media from what source?  Blu-ray disc media is quite different from 4K, optimized for streaming.  I believe the metadata optimization is also different and if the media has not been transcoded to work best with streaming it will probably have problems playing back on all systems.  Why not test prepared 4K streaming demo videos instead?  Otherwise, you will never know if the file is causing the issues and you are looking for answers from some code issue, when it is not the cause of the stuttering.  Delivering content to clients in 4K for blu-ray masters, blu-ray disc files and 4K streaming are all different files.

https://duckduckgo.com/?q=4K+optimized+for+blu-ray+playback+vs.+streaming&ia=web
https://duckduckgo.com/?q=sample+4K+test+video+streaming&ia=web

I can try some of those, but would be curious if any of them are long enough. It seems pretty consistent that the crashes are around 30-50 minutes in (usually about 34ish). I will check, though.

Most of it is either 4K UHD or Blu-ray rips of my collection using makemkv. No further processing. Some of the TV show episodes are 4k downloads. 

EDIT: But again, if the issue were the files themselves then that wouldn't explain why the issue seems limited to the official Apple TV emby app. As I've mentioned, Infuse pointed at the same emby server, Infuse pointed at jellyfin, a third party jellyfin client, and plex (all on the same Apple TV playing the same files) work just fine without any issues. Hell, even the official emby app on Roku plays the files just fine. So I could be wrong, but I highly doubt it's the files.

Edited Monday at 07:50 PM by vidkun

[SamES 1091]

3 hours ago, vidkun said:

But that still begs the question: why would it work WITH transcoding, but not without? And why limited to the Apple TV official app when Infuse works fine on same ATV from emby (as well as Plex and Jellyfin)?

If your player is set to auto in the app, then forcing transcoding might be switching between the native and mpv players. 

[vidkun 13]

14 hours ago, SamES said:

If your player is set to auto in the app, then forcing transcoding might be switching between the native and mpv players. 

Could be, but as I mentioned above, I already tried manually changing it to mpv in the settings without any improvement before Luke told me to change it back to auto.

[vidkun 13]

So far, playing videos with it forcing transcoding seems to be working just fine. I have been able to play three or four different full-length episodes of shows without any issues this way. The only issue I have noticed so far is that forcing the transcoding screws up the ability to use subtitles, but that may be because I disabled the automatic subtitle extraction per a previous recommendation above.

Next time I get a chance, I will give it another shot using direct play of one of the episodes that I previously played just fine via transcoding.

[vidkun 13]

I went back and rewatched one of the episodes that had played fine via transcoding and watched it direct play and it played just fine all the way through. So I decided to try my luck and watch a new episode direct play to see if it would play all the way through but about 25 minutes in it froze up again and the app crashed. After completely closing out of the app and reopening it I was able to play that new episode via transcode and play it through all the way just fine again.