Topic: Pulseaudio Choppy Playback (also slowed down)

[aaronegger]

Hi there,

i have an issue with bass in combination with pulseaudio (12.2) and raspbian on a raspberry pi model 3b+.
Since the application needs to be started after booting pulseaudio runs in system mode.
Therefore a unit file for the service has been created:

Code: [Select]

Description=PulseAudio system server

[Service]
Type=notify
ExecStart=/usr/bin/pulseaudio --daemonize=no -vvvv --high-priority --system --disallow-exit --no-cpu-limit --log-target=journal
ExecReload=/bin/kill -HUP $MAINPID
Restart=on-failure
Nice=-11
CPUSchedulingPolicy=rr
CPUSchedulingPriority=90
IOSchedulingClass=realtime
IOSchedulingPriority=0

[Install]
WantedBy=multi-user.target" > /etc/systemd/system/pulseaudio.service

And pulseaudio reconfigured to not autospawn:
/etc/pulse/client.conf

Code: [Select]

default-server = /var/run/pulse/native
autospawn = no


Normally we use the usb card, which works most of the time good.
But the issue is that it is only most of the time.
The issue occurs immedialty on the onboard chip.

The sound get choppy (stuttering) and the playback seems to be slower. It is like a distorted slow motion playback.

As soon as try to play an audio file with the vlc the slow motion effects disappears. And after a while the playback is nearly normal.
But if restart the pulseaudio service this issue occurs again.
On some devices this issue occurs on the usb soundchip after several hours. At this period of time (about 30min) the playback is also reported as stalled by bass.

I have tried a lot of things like setting the BASS_CONFIG_DEV_BUFFER to 150, BASS_CONFIG_BUFFER to 1000 (prior Bass_init).
Editing the /etc/pulse/daemon.conf file by adjusting the default-fragemnts, default-fragment-size-msec.
Adjusting the Nice, CPUSchedulingPolicy, CPUSchedulingPriority, IOSchedulingClass and IOSchedulingPriority values at the service unit files (the audioplaying software using bass is also managed by systemd).

I googled a lot. Looked through the issues at the pulseaudio project and tried the recommendations of several users.
But nothing changed a thing.
The next thing we will try would be to remove pulseaudio completely. But i am not sure about the sideeffects this could cause.

But maybe anybody already had similar issues with bass and/or pulseaudio on a raspberry pi and could help.
i appreciate any help you can give me

Best wishes
Aaron

[aaronegger]

Pulseaudio reports following devices:

Code: [Select]

Sink #1
        State: SUSPENDED
        Name: alsa_output.platform-bcm2835_audio.analog-stereo
        Description: Built-in Audio Analog Stereo
        Driver: module-alsa-card.c
        Sample Specification: s16le 2ch 44100Hz
        Channel Map: front-left,front-right
        Owner Module: 5
        Mute: no
        Volume: front-left: 9830 /  15% / -49.44 dB,   front-right: 9830 /  15% / -49.44 dB
                balance 0.00
        Base Volume: 65536 / 100% / 0.00 dB
        Monitor Source: alsa_output.platform-bcm2835_audio.analog-stereo.monitor
        Latency: 0 usec, configured 0 usec
        Flags: HARDWARE DECIBEL_VOLUME LATENCY
        Properties:
                alsa.resolution_bits = "16"
                device.api = "alsa"
                device.class = "sound"
                alsa.class = "generic"
                alsa.subclass = "generic-mix"
                alsa.name = "bcm2835 Headphones"
                alsa.id = "bcm2835 Headphones"
                alsa.subdevice = "0"
                alsa.subdevice_name = "subdevice #0"
                alsa.device = "0"
                alsa.card = "2"
                alsa.card_name = "bcm2835 Headphones"
                alsa.long_card_name = "bcm2835 Headphones"
                alsa.driver_name = "snd_bcm2835"
                device.bus_path = "platform-bcm2835_audio"
                sysfs.path = "/devices/platform/soc/3f00b840.mailbox/bcm2835_audio/sound/card2"
                device.form_factor = "internal"
                device.string = "hw:2"
                device.buffering.buffer_size = "131072"
                device.buffering.fragment_size = "131072"
                device.access_mode = "mmap+timer"
                device.profile.name = "analog-stereo"
                device.profile.description = "Analog Stereo"
                device.description = "Built-in Audio Analog Stereo"
                alsa.mixer_name = "Broadcom Mixer"
                module-udev-detect.discovered = "1"
                device.icon_name = "audio-card"
        Ports:
                analog-output: Analog Output (priority: 9900)
        Active Port: analog-output
        Formats:
                pcm

Sink #2
        State: RUNNING
        Name: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo
        Description: Audio Adapter (Unitek Y-247A) Analog Stereo
        Driver: module-alsa-card.c
        Sample Specification: s16le 2ch 44100Hz
        Channel Map: front-left,front-right
        Owner Module: 6
        Mute: no
        Volume: front-left: 52428 /  80% / -5.81 dB,   front-right: 52428 /  80% / -5.81 dB
                balance 0.00
        Base Volume: 65536 / 100% / 0.00 dB
        Monitor Source: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo.monitor
        Latency: 118675 usec, configured 126000 usec
        Flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY
        Properties:
                alsa.resolution_bits = "16"
                device.api = "alsa"
                device.class = "sound"
                alsa.class = "generic"
                alsa.subclass = "generic-mix"
                alsa.name = "USB Audio"
                alsa.id = "USB Audio"
                alsa.subdevice = "0"
                alsa.subdevice_name = "subdevice #0"
                alsa.device = "0"
                alsa.card = "1"
                alsa.card_name = "USB Audio Device"
                alsa.long_card_name = "C-Media Electronics Inc. USB Audio Device at usb-3f980000.usb-1.4, full speed"
                alsa.driver_name = "snd_usb_audio"
                device.bus_path = "platform-3f980000.usb-usb-0:1.4:1.0"
                sysfs.path = "/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4:1.0/sound/card1"
                udev.id = "usb-C-Media_Electronics_Inc._USB_Audio_Device-00"
                device.bus = "usb"
                device.vendor.id = "0d8c"
                device.vendor.name = "C-Media Electronics, Inc."
                device.product.id = "0014"
                device.product.name = "Audio Adapter (Unitek Y-247A)"
                device.serial = "C-Media_Electronics_Inc._USB_Audio_Device"
                device.string = "front:1"
                device.buffering.buffer_size = "352800"
                device.buffering.fragment_size = "176400"
                device.access_mode = "mmap+timer"
                device.profile.name = "analog-stereo"
                device.profile.description = "Analog Stereo"
                device.description = "Audio Adapter (Unitek Y-247A) Analog Stereo"
                alsa.mixer_name = "USB Mixer"
                alsa.components = "USB0d8c:0014"
                module-udev-detect.discovered = "1"
                device.icon_name = "audio-card-usb"
        Ports:
                analog-output-speaker: Speakers (priority: 10000)
        Active Port: analog-output-speaker
        Formats:
                pcm


[aaronegger]

Pulseaudio log when playing using the onboard audio chip (while the sound is stuttering)

Code: [Select]

pulseaudio[2476]: memblockq requested: maxlength=4194304, tlength=0, base=4, prebuf=1, minreq=0 maxrewind=0
pulseaudio[2476]: memblockq sanitized: maxlength=4194304, tlength=4194304, base=4, prebuf=4, minreq=4 maxrewind=0
pulseaudio[2476]: Final latency 80,00 ms = 40,00 ms + 40,00 ms
pulseaudio[2476]: Latency set to 26,00ms
pulseaudio[2476]: hwbuf_unused=126488
pulseaudio[2476]: setting avail_min=32416
pulseaudio[2476]: Latency set to 26,00ms
pulseaudio[2476]: hwbuf_unused=126488
pulseaudio[2476]: setting avail_min=32416
pulseaudio[2476]: Wakeup from ALSA!
pulseaudio[2476]: Underrun!
pulseaudio[2476]: Increasing wakeup watermark to 15,99 ms
pulseaudio[2476]: Underrun!
pulseaudio[2476]: Increasing minimal latency to 36,00 ms
pulseaudio[2476]: Latency set to 36,00ms
pulseaudio[2476]: hwbuf_unused=124724
pulseaudio[2476]: setting avail_min=32064
pulseaudio[2476]: Latency set to 36,00ms
pulseaudio[2476]: hwbuf_unused=124724
pulseaudio[2476]: setting avail_min=32064
pulseaudio[2476]: Requesting rewind due to corking
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1832 bytes ago (4516 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1832 bytes ago (4516 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5292 bytes ago (1056 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5292 bytes ago (1056 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5292 bytes ago (1056 bytes ahead in playback buffer)
pulseaudio[2476]: Underrun!
pulseaudio[2476]: Increasing wakeup watermark to 25,99 ms
pulseaudio[2476]: Requesting rewind due to end of underrun.
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: Requesting rewind due to end of underrun.
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: Wakeup from ALSA!
pulseaudio[2476]: Implicit underrun of 'ALSA Playback'
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 24 bytes ago (6324 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 24 bytes ago (6324 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 24 bytes ago (6324 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1788 bytes ago (4560 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1788 bytes ago (4560 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1788 bytes ago (4560 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 3552 bytes ago (2796 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5316 bytes ago (1032 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5316 bytes ago (1032 bytes ahead in playback buffer)
pulseaudio[2476]: Requesting rewind due to end of underrun.
pulseaudio[2476]: Requesting rewind due to uncorking
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: Requesting rewind due to corking
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1816 bytes ago (4532 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 1816 bytes ago (4532 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 3652 bytes ago (2696 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5296 bytes ago (1052 bytes ahead in playback buffer)
pulseaudio[2476]: alsa_output.platform-bcm2835_audio.analog-stereo: Found underrun 5296 bytes ago (1052 bytes ahead in playback buffer)
pulseaudio[2476]: Requesting rewind due to end of underrun.
pulseaudio[2476]: Requesting rewind due to uncorking
pulseaudio[2476]: Requested to rewind 6348 bytes.
pulseaudio[2476]: Limited to 6092 bytes.
pulseaudio[2476]: before: 1523
pulseaudio[2476]: after: 0
pulseaudio[2476]: Tried rewind, but was apparently not possible.
pulseaudio[2476]: Wakeup from ALSA!


[aaronegger]

Pulseaudio log when playing using the usb audio chip (while the sound is stuttering)

Code: [Select]

pulseaudio[457]: hwbuf_unused=332340
pulseaudio[457]: setting avail_min=83968
pulseaudio[457]: Requesting rewind due to latency change.
pulseaudio[457]: Requested volume: front-left: 52428 /  80% / -5.81 dB,   front-right: 52428 /  80% / -5.81 dB
pulseaudio[457]: Got hardware volume: front-left: 54094 /  83% / -5.00 dB,   front-right: 54094 /  83% / -5.00 dB
pulseaudio[457]: Calculated software volume: front-left: 63518 /  97% / -0.81 dB,   front-right: 63518 /  97% / -0.81 dB (accurate-enough=no)
pulseaudio[457]: Volume not changing
pulseaudio[457]: Requested to rewind 352800 bytes.
pulseaudio[457]: Limited to 351488 bytes.
pulseaudio[457]: before: 87872
pulseaudio[457]: after: 87872
pulseaudio[457]: Rewound 351488 bytes.
pulseaudio[457]: Processing rewind...
pulseaudio[457]: latency = 3515
pulseaudio[457]: Have to rewind 351488 bytes on render memblockq.
pulseaudio[457]: Processing rewind...
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: state: IDLE -> RUNNING
pulseaudio[457]: Requesting rewind due to end of underrun.
pulseaudio[457]: Requested to rewind 20460 bytes.
pulseaudio[457]: Limited to 19148 bytes.
pulseaudio[457]: before: 4787
pulseaudio[457]: after: 4787
pulseaudio[457]: Rewound 19148 bytes.
pulseaudio[457]: Processing rewind...
pulseaudio[457]: latency = 7463
pulseaudio[457]: Have to rewind 19148 bytes on render memblockq.
pulseaudio[457]: Processing rewind...
pulseaudio[457]: Implicit underrun of 'ALSA Playback'
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 14912 bytes ago (5548 bytes ahead in playback buffer)
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 14912 bytes ago (5548 bytes ahead in playback buffer)
[...]
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: Sink alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo becomes idle, timeout in 5 seconds.
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: Found underrun 17032 bytes ago (2372 bytes ahead in playback buffer)
pulseaudio[457]: hwbuf_unused=0
pulseaudio[457]: setting avail_min=83968
pulseaudio[457]: Requested volume: front-left: 52428 /  80% / -5.81 dB,   front-right: 52428 /  80% / -5.81 dB
pulseaudio[457]: Got hardware volume: front-left: 54094 /  83% / -5.00 dB,   front-right: 54094 /  83% / -5.00 dB
pulseaudio[457]: Calculated software volume: front-left: 63518 /  97% / -0.81 dB,   front-right: 63518 /  97% / -0.81 dB (accurate-enough=no)
pulseaudio[457]: Volume not changing
pulseaudio[457]: Requested to rewind 352800 bytes.
pulseaudio[457]: Limited to 19148 bytes.
pulseaudio[457]: before: 4787
pulseaudio[457]: after: 4787
pulseaudio[457]: Rewound 19148 bytes.
pulseaudio[457]: Processing rewind...
pulseaudio[457]: latency = 4130
pulseaudio[457]: Processing rewind...
pulseaudio[457]: alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo: state: RUNNING -> IDLE
pulseaudio[457]: Sink alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo becomes idle, timeout in 5 seconds.
pulseaudio[457]: Hmm, no streams around, trying to vacuum.
pulseaudio[457]: Freeing input 2686 "ALSA Playback"
pulseaudio[457]: Negotiated format: pcm, format.sample_format = "\"float32le\""  format.rate = "44100"  format.channels = "2"  format.channel_map = "\"front-left,front-right\""
pulseaudio[457]: Trying to change sample rate
pulseaudio[457]: Sink alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo becomes busy, resuming.
pulseaudio[457]: Sink alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo becomes idle, timeout in 5 seconds.
pulseaudio[457]: Forcing resampler 'copy', because of fixed, identical sample rates.
pulseaudio[457]: Resampler:
pulseaudio[457]:   rate 44100 -> 44100 (method copy)
pulseaudio[457]:   format float32le -> s16le (intermediate s16le)
pulseaudio[457]:   channels 2 -> 2 (resampling 2)
pulseaudio[457]: memblockq requested: maxlength=33554432, tlength=0, base=4, prebuf=0, minreq=1 maxrewind=0
pulseaudio[457]: memblockq sanitized: maxlength=33554432, tlength=33554432, base=4, prebuf=0, minreq=4 maxrewind=0
pulseaudio[457]: Created input 2687 "ALSA Playback" on alsa_output.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.analog-stereo with sample spec float32le 2ch 44100Hz and channel map front-left,front-right
pulseaudio[457]:     media.name = "ALSA Playback"
pulseaudio[457]:     application.name = "ALSA plug-in [audioplayer]"
pulseaudio[457]:     native-protocol.peer = "UNIX socket client"
pulseaudio[457]:     native-protocol.version = "32"
pulseaudio[457]:     application.process.id = "677"
pulseaudio[457]:     application.process.user = "audioplayer"
pulseaudio[457]:     application.process.host = "e27-EC-86-6A-40"
pulseaudio[457]:     application.process.binary = "audioplayer"
pulseaudio[457]:     application.language = "C"
pulseaudio[457]:     application.process.machine_id = "51149e1e30c0416c8c6ebf5d3e0bf457"
pulseaudio[457]:     module-stream-restore.id = "sink-input-by-application-name:ALSA plug-in [audioplayer]"
pulseaudio[457]: Requested tlength=40.00 ms, minreq=10.00 ms
pulseaudio[457]: Early requests mode enabled, configuring sink latency to minreq.
pulseaudio[457]: Could not configure a sufficiently low latency. Early requests might not be satisifed.
pulseaudio[457]: Requested latency=10.00 ms, Received latency=116.00 ms
pulseaudio[457]: memblockq requested: maxlength=4194304, tlength=47984, base=8, prebuf=10584, minreq=3528 maxrewind=0
pulseaudio[457]: memblockq sanitized: maxlength=4194304, tlength=47984, base=8, prebuf=10584, minreq=3528 maxrewind=0
pulseaudio[457]: Final latency 252.01 ms = 116.01 ms + 2*10.00 ms + 116.00 ms


[Ian @ un4seen]

Please confirm what BASS version is currently being used (with BASS_GetVersion), and whether it's hardfp or aarch64. Here also is the latest build that you could try:

   www.un4seen.com/stuff/bass-linux-arm.zip

Regarding removing PulseAudio, it should usually be possible to just not use it without having to totally remove it, by simply changing the "device" parameter in your BASS_Init call. So long as nothing else is using PulseAudio at the time, that should work fine. The first hardware "hw" device (if there are any) is at number 2. If you have multiple devices then you can use BASS_GetDeviceInfo to enumerate them and find the one you want.

[aaronegger]

Hi Ian,

thank you for answering 

The bass version is 2.4.16.11 and bass fx has the version 2.4.12.5.
Both are hardfp.
I got the last bass version at the end of december 2021 to fix an volume issue, where system volume changes were not detected if changed externally.
But i will try with the current version.

I know that this issue could have a ton of different reasons with most of them not caused by bass, but maybe you already saw a similiar situations and found possible solutions for that.

We found some things that could caused these buffer underruns, but since we don't know the actual reason we are just poking around and keep observating if the issue occurs again.

Do you have any idea what could cause buffer underuns? Or is the buffer underrun the main issue or just an issue caused by another issue?
The only thing i found about buffer underun is that the input buffer is not filled fast enough for a smooth playback. But i have no clue what could cause this..

We suspected that the sd card of the pi is overloaded or that the files are written and read from the swap instead the ram which maybe cause issues like that.
But only time will tell if this was indeed the root or one of the issues that caused this.

So if you have any idea, also ideas that not belong to bass, please let me know.
I would appreciate it very much.

[Ian @ un4seen]

No, I'm not sure what would be causing the problem, but to perhaps narrow it down please see if you can reproduce it with ALSA alone (no PulseAudio) and also the examples from the Linux BASS package. To build the examples, you should replace the makefile.in file with the one from the ARM Linux package. The CONTEST example includes a device selection option, so you could also use that to try ALSA alone.