[SOLVED] Playback of mp3 via smb-share is stuttering

[a.kynr]

You said this stuttering began when you upgraded from 9.3.3 to 9.3.6. Looking through the release notes, I see that with 9.3.4, the kernel was updated to 6.12.25. If.you really want to, you could try installing first 9.3.3 and then 9.3.4 to see if that’s where the stuttering starts. (Previous releases are available on the github repro.)

I did a fresh install with 9.3.3, and to my surprise there is stuttering when playing mp3s as well. No problem with flacs btw. So it's not related to the update of the kernel I think. I recognised the stuttering after the update to 9.3.6, but maybe the issue existed before. Mostly I play flacs, could be that I didn't recognise it because I didn't play any mp3s recently. 

Incidentally, you can check the MPD log (/var/log/mpd/log) to see if underrun messages are being thrown by MPD while the stuttering is occurring. Note: I don’t recall if you have to increase the MPD logging level to Verbose to see these. 

This helped me a lot. The MPD log shows some "alsa_output: Decoder is too slow; playing silence to avoid xrun" messages every five seconds. 

Code:

2025-07-02T17:57:36 client: [127.0.0.1:44770] client connected
2025-07-02T17:57:36 client: [127.0.0.1:44770] process command "status"
2025-07-02T17:57:36 client: [127.0.0.1:44770] command returned 0
2025-07-02T17:57:36 client: [127.0.0.1:44770] process command "idle"
2025-07-02T17:57:36 client: [127.0.0.1:44770] command returned 1
2025-07-02T17:57:36 client: [127.0.0.1:44776] client connected
2025-07-02T17:57:36 client: [127.0.0.1:44776] process command "playlistinfo"
2025-07-02T17:57:36 client: [127.0.0.1:44776] command returned 0
2025-07-02T17:57:36 client: [127.0.0.1:44776] process command "close"
2025-07-02T17:57:36 client: [127.0.0.1:44776] command returned 4
2025-07-02T17:57:36 client: [127.0.0.1:44776] disconnected
2025-07-02T17:57:37 client: [127.0.0.1:51976] client connected
2025-07-02T17:57:37 client: [127.0.0.1:51976] process command "pause"
2025-07-02T17:57:37 client: [127.0.0.1:51976] command returned 0
2025-07-02T17:57:37 client: [127.0.0.1:51976] process command "close"
2025-07-02T17:57:37 client: [127.0.0.1:51976] command returned 4
2025-07-02T17:57:37 client: [127.0.0.1:51976] disconnected
2025-07-02T17:57:37 client: [127.0.0.1:44770] process command "status"
2025-07-02T17:57:37 client: [127.0.0.1:44770] command returned 0
2025-07-02T17:57:37 client: [127.0.0.1:44770] process command "currentsong"
2025-07-02T17:57:37 client: [127.0.0.1:44770] command returned 0
2025-07-02T17:57:37 output: closed "ALSA Default" (alsa)
2025-07-02T17:57:38 client: [127.0.0.1:44770] process command "lsinfo \"NAS/test/2011_Anna_Calvi/07_Blackout.flac\""
2025-07-02T17:57:38 client: [127.0.0.1:44770] command returned 0
2025-07-02T17:57:38 client: [127.0.0.1:44770] process command "close"
2025-07-02T17:57:38 client: [127.0.0.1:44770] command returned 4
2025-07-02T17:57:38 client: [127.0.0.1:44770] disconnected
2025-07-02T17:57:38 client: [127.0.0.1:51986] client connected
2025-07-02T17:57:38 client: [127.0.0.1:51986] process command "status"
2025-07-02T17:57:38 client: [127.0.0.1:51986] command returned 0
2025-07-02T17:57:38 client: [127.0.0.1:51986] process command "idle"
2025-07-02T17:57:38 client: [127.0.0.1:51986] command returned 1
2025-07-02T17:57:38 client: [127.0.0.1:52000] client connected
2025-07-02T17:57:38 client: [127.0.0.1:52000] process command "playlistinfo"
2025-07-02T17:57:38 client: [127.0.0.1:52000] command returned 0
2025-07-02T17:57:38 client: [127.0.0.1:52000] process command "close"
2025-07-02T17:57:38 client: [127.0.0.1:52000] command returned 4
2025-07-02T17:57:38 client: [127.0.0.1:52000] disconnected
2025-07-02T17:57:39 client: [127.0.0.1:52016] client connected
2025-07-02T17:57:39 client: [127.0.0.1:52016] process command "play 12"
2025-07-02T17:57:39 playlist: play 12:"NAS/test/2014_Adamlar_Eski-Dostum-Tankla-Gelmiş/03 Bi Öyle Bi Böyle.mp3"
2025-07-02T17:57:39 decoder_thread: probing plugin mpg123
2025-07-02T17:57:39 decoder: audio_format=44100:16:2, seekable=true
2025-07-02T17:57:39 alsa_output: opened "_audioout" type=COPY
2025-07-02T17:57:39 alsa_output: buffer: size=64..65536 time=1451..1486078
2025-07-02T17:57:39 alsa_output: period: size=32..32768 time=725..743039
2025-07-02T17:57:39 alsa_output: default period_time = buffer_time/4 = 500000/4 = 125000
2025-07-02T17:57:39 alsa_output: format=S24_LE (Signed 24 bit Little Endian)
2025-07-02T17:57:39 alsa_output: buffer_size=22050 period_size=4410
2025-07-02T17:57:39 output: opened "ALSA Default" (alsa) audio_format=44100:24:2
2025-07-02T17:57:39 output: converting in=44100:16:2 -> f=44100:24:2 -> out=44100:24:2
2025-07-02T17:57:39 client: [127.0.0.1:52016] command returned 0
2025-07-02T17:57:39 playlist: queue song 13:"NAS/test/2014_Adamlar_Eski-Dostum-Tankla-Gelmiş/04 Koca Yaşlı Şişko Dünya.mp3"
2025-07-02T17:57:39 client: [127.0.0.1:52016] process command "close"
2025-07-02T17:57:39 client: [127.0.0.1:52016] command returned 4
2025-07-02T17:57:39 client: [127.0.0.1:52016] disconnected
2025-07-02T17:57:39 client: [127.0.0.1:51986] process command "status"
2025-07-02T17:57:39 client: [127.0.0.1:51986] command returned 0
2025-07-02T17:57:39 client: [127.0.0.1:51986] process command "currentsong"
2025-07-02T17:57:39 client: [127.0.0.1:51986] command returned 0
2025-07-02T17:57:41 client: [127.0.0.1:51986] process command "lsinfo \"NAS/test/2014_Adamlar_Eski-Dostum-Tankla-Gelmiş/03 Bi Öyle Bi Böyle.mp3\""
2025-07-02T17:57:41 client: [127.0.0.1:51986] command returned 0
2025-07-02T17:57:41 client: [127.0.0.1:51986] process command "close"
2025-07-02T17:57:41 client: [127.0.0.1:51986] command returned 4
2025-07-02T17:57:41 client: [127.0.0.1:51986] disconnected
2025-07-02T17:57:41 client: [127.0.0.1:52018] client connected
2025-07-02T17:57:41 client: [127.0.0.1:52018] process command "status"
2025-07-02T17:57:41 client: [127.0.0.1:52018] command returned 0
2025-07-02T17:57:41 client: [127.0.0.1:52018] process command "idle"
2025-07-02T17:57:41 client: [127.0.0.1:52018] command returned 1
2025-07-02T17:57:41 client: [127.0.0.1:52026] client connected
2025-07-02T17:57:41 client: [127.0.0.1:52026] process command "playlistinfo"
2025-07-02T17:57:41 client: [127.0.0.1:52026] command returned 0
2025-07-02T17:57:41 client: [127.0.0.1:52026] process command "close"
2025-07-02T17:57:41 client: [127.0.0.1:52026] command returned 4
2025-07-02T17:57:41 client: [127.0.0.1:52026] disconnected
2025-07-02T17:57:43 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:57:48 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:57:53 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:57:58 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:58:03 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:58:08 alsa_output: Decoder is too slow; playing silence to avoid xrun
2025-07-02T17:58:13 alsa_output: Decoder is too slow; playing silence to avoid xrun

So it seems the mpg123 decoder has issues handling my mp3 files. Maybe connection issues after all? 
Like I said the flac plugin and ffmpeg (for mka-files) are working properly in my setup, and that's what the logs say, too.

The next thing I did was enabling dev tweaks on moodeaudio (like Tim is describing it here: https://moodeaudio.org/forum/showthread....3#pid47753) and disabling the mpg123 decoder on my custom mpd.conf. This lead to using the mad decoder instead, which works fine as far as I can say. 

This is a solution I can live with. 
Do you know if there is any other or better way to use a preferred decoder or enable/disable one? 

(For the record, increasing audio buffer or enabling input cache didn't change the stuttering...)

Thanks a lot for your help! 

Best,
a.kynr