Stutter/freezes on 4k files

[Monovertex 1]

Hey all! I've been encountering stutters and freezes on the iOS app recently. From what I can tell, this happens on 4K files, regardless if the file is HDR/DoVi/SDR. When the issue started, the video playback would freeze for a second, starting very rarely and then getting increasingly more repeated; the video was lagging behind the audio, and I had to restart the app. In the past week or so, the issue changed, in the sense that now both video and audio freeze from time to time, sometimes more often, sometimes less often, with no discernible pattern. I would guess that it's a different, or at least a changed bug.

I have an iPhone 12 Pro Max and Emby 2.2.13. From what I know all the files with these issues were direct playing on all three streams. 

I have attached the server log from the latest file I tried to play that had this issue, as well as a picture showing the direct play.

Let me know if I can provide further information or if I can try anything to debug the issue.

embyserver.txt

Edited October 2, 2023 by Monovertex

[Monovertex 1]

This is still happening for me, even after updating to latest releases.

Furthermore, if I try to reduce the resolution and/or bitrate to force a transcode, the app grinds to a halt completely, even though the hardware should be more than enough and the CPU is barely at 5-10% usage.

So it's pretty much unusable on iOS.

Edited December 22, 2023 by Monovertex

[Monovertex 1]

I had some issues with my hardware acceleration settings, but fixed those, and now transcoding should go as smooth as possible. The server admin panel is showing the playback as working with no issues and no throttling, however the playback keeps stuttering on the iOS app (I downgraded the quality to 1080p 10mbs).

This is definitely an iOS app issue, because if I play the same file with the same quality setting on my TV it plays just fine, and the server handles both transcodes without breaking a sweat.

[Luke 37116]

On 12/22/2023 at 2:38 AM, Monovertex said:

I had some issues with my hardware acceleration settings, but fixed those, and now transcoding should go as smooth as possible. The server admin panel is showing the playback as working with no issues and no throttling, however the playback keeps stuttering on the iOS app (I downgraded the quality to 1080p 10mbs).

This is definitely an iOS app issue, because if I play the same file with the same quality setting on my TV it plays just fine, and the server handles both transcodes without breaking a sweat.

@Monovertexcan you please provide the corresponding emby server and ffmpeg log files? Thanks !

[Monovertex 1]

On 27/12/2023 at 01:28, Luke said:

@Monovertexcan you please provide the corresponding emby server and ffmpeg log files? Thanks !

@LukeThank you for the reply!

The issue with transcoded files doesn't happen anymore. They play fine on the iOS app now, so we can leave that aside.

However, the issue described in my OP (4K direct-play stuttering on the iOS app) is still happening. The file plays just fine on my LG TV. I'm attaching an updated log from today, after the stuttering occurred.

Let me know if I can provide any other data.

directplay-ios-stutter-embyserver.txt

[Luke 37116]

On 1/3/2024 at 7:34 AM, Monovertex said:

@LukeThank you for the reply!

The issue with transcoded files doesn't happen anymore. They play fine on the iOS app now, so we can leave that aside.

However, the issue described in my OP (4K direct-play stuttering on the iOS app) is still happening. The file plays just fine on my LG TV. I'm attaching an updated log from today, after the stuttering occurred.

Let me know if I can provide any other data.

directplay-ios-stutter-embyserver.txt 187.14 kB · 0 downloads

Hi, can you try something lower bitrate? How does that compare?

[Monovertex 1]

13 hours ago, Luke said:

Hi, can you try something lower bitrate? How does that compare?

Your comment made me realize that I was connected to the 2.4GHz network on my phone, while my TV is on the 5GHz one. I switched and will report back if the issue crops up again.

The issue only started appearing a few months ago, before that I never had any stutter, and I always play high-bitrate files. I'm thinking maybe I switched to the 2.4GHz network at some point and that would have caused the stutters.