Plexamp IOS Stuttering

Server Version#: 4.142.2
Player Version#: Plexamp 4.11.5 iOS

Server is running on Windows 11

I’ve just started cataloging my music collection and decided to give Plexamp a try. I’m digging it for the most part but fairly often I get massive stuttering when playing back FLAC media. I haven’t noticed any with MP3, but with FLAC it might play fine for a minute then skip back a few seconds play for a few and skip again. The time counting stays accurate and the song audio will end abruptly and go to the next track because the actual time is finished.

It doesn’t matter if I am on cellular or WiFi it will do the same. I don’t have any issues with video playback even at high bitrate 4K direct play content. I consistently get over 600mbps up and down from my phone so I don’t think it’s a bandwidth issue at all. Any help is greatly appreciated!

Thanks in advance!

Plexamp-Logs-2025-01-04-2.zip (497.7 KB)

I do see some underflow/buffering in the logs. These look like super high bitrate FLACs? And your max cache is set to 512 MB which is going to lead to churn when each file is 10s of MB.

Elan

I changed the cache to 2GB in order to try and troubleshoot things to see if it changes anything.

It has done it with 48/24 FLAC and 44/16 FLAC files.

It didn’t help. About a minute into Black Hole Sun it starts stuttering

Plexamp-Logs-2025-01-05-1.zip (534.2 KB)

by any chance is your phone storage almost full ?

No I have 98gb free space

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OK, so I see Black Hole Sun buffering at the start, and then playing flawlessly until 60 seconds, when you paused it.

About a minute into Black Hole Sun it starts stuttering

Given you’re telling me this, and there is no sign of any issue in the audio stack, the likely scenario is whatever you’re playing to (bluetooth headphones? airplay? something?) is responsible for the stuttering.

Yes I paused it right after it began. I was using Bluetooth headphones

Just for kicks I tried out Prism player for iOS and connected to my Plex server. Using the same Bluetooth headphones there’s zero issues playing the same media.

I also played Plexamp directly through my iPhone speakers and it still stutters at about the 1 minute mark. It’s definitely not related to Bluetooth.

I’m not sure what to say, there are no indications of anything untoward happening in that first minute.

Can you give us more details about your device?

It’s an iPhone 15 Pro Max, iOS 18.2. I’m not on any beta versions. 256gb model with 96gb free space.

anything repeatable, or does it seem to randomly occur with any/all flac files? does it happen with downloaded flac files?

(also just tried playing some files here with prism … i’m not too familiar with the app … does prism transcode?)

Yes it’s repeatable. Usually about a minute in. Some right at a minute, and some a few seconds after. Doesn’t matter if I self encoded from CD WAV with FFMPEG or downloaded. It doesn’t happen on every song but it does happen to most that I play. I’ve noticed once it starts stuttering it does it several times during playback, even if I pause and resume it, or seek to where it would normally start. It’s guaranteed to happen on a file that has done it before.

I can play that same media with Prism, or stream over SMB to VLC on my phone and it plays perfectly fine.

Any chance you can upload one of the FLACs in question which reproduces the issue?

Sure here you go. This one did it at 0:11 and again at 1:05. I’ve included a new log as well. When it changed to Violet hill, the time marker read 0:14 on that song.

I also deleted Plexamp and reinstalled it. It seemed to help some and it didn’t do skip on Black Hole Sun but it still does it on some others including the attached. Doesn’t seem to be a pattern that I can tell. Doesn’t matter if I directly play the file or it’s a part of the library radio like in this example.

It wouldn’t let me upload here (over 8MB) but here’s a link to the file in my iCloud.

i played that file many times without issue here (win11 server, plexamp on iOS and other platforms) … no flac/decode errors according to dbpoweramp, all good

interesting that reinstalling the app seemed to change things

I was able to capture this phenomenon with screen record. Not sure why I didn’t think of this to begin with.

Here’s a few more examples. Songs played perfectly up until the point they stutter and played fine after.

if you get a track that stutters, then clear the cache (settings > playback > caching > delete caches), then play the same track again … does the stuttering repeat? or does it go away or happen at a different time?

Nothing changes when I do that