Building for a very lightweight platform? #695

seamusdemora · 2024-04-16T13:35:44Z

seamusdemora
Apr 16, 2024

Hello again,
Back with another question: I want to try bluez-alsa on a tiny little Raspberry Pi 2W. I'm currently running the "Lite" (headless) version of the RPi OS 'bookworm' (64-bit). I could run the 'bullseye' version of the OS if that would "improve my chances" of success. Any thoughts or opinions on that?

~~If I do the build on another platform, is there an install procedure (I assume that there are config files that get set up during the build)??~~ (answered in the installation README.md)

~~Is there a list of packages I must have to build/'make' bluez-alsa?~~ (answered in the wiki)

Thanks for your help!

Answered by borine

Apr 16, 2024

I run bluealsa on an even more tiny raspberry pi zero (mark1, 32bit processor) using bookworm, and previously with bullseye, buster, and stretch. So my opinion is no problem (depending on exactly you are expecting it to do!)

View full answer

borine · 2024-04-16T14:38:19Z

borine
Apr 16, 2024
Collaborator

I run bluealsa on an even more tiny raspberry pi zero (mark1, 32bit processor) using bookworm, and previously with bullseye, buster, and stretch. So my opinion is no problem (depending on exactly you are expecting it to do!)

11 replies

borine Apr 17, 2024
Collaborator

Does it make any difference whether I am running on a 64-bit OS - or a 32-bit OS?

No, bluealsa works fine as a 32-bit or 64-bit application, so long as it is compiled for its host system.

Does it make any difference whether I am running bullseye vs bookworm?

No, I've used it without issues on both.

seamusdemora Apr 17, 2024
Author

THE ISSUE DESCRIBED BELOW HAS BEEN RESOLVED, BUT SEE QUESTION AT END OF REPLY

Uh-oh... what did I do wrong?

$ mpg123 -o alsa -a bluealsa rainstorm.mp3
High Performance MPEG 1.0/2.0/2.5 Audio Player for Layers 1, 2 and 3
	version 1.31.2; written and copyright by Michael Hipp and others
	free software (LGPL) without any warranty but with best wishes
ALSA lib ../../../src/asound/bluealsa-pcm.c:1477:(_snd_pcm_bluealsa_open) Couldn't get BlueALSA PCM: PCM not found
[src/libout123/modules/alsa.c:open_alsa():181] error: cannot open device bluealsa
[src/libout123/libout123.c:check_output_module():947] error: Module 'alsa' device open failed.
[src/libout123/libout123.c:out123_open():439] error: Found no driver out of [alsa] working with device bluealsa.
main: [src/mpg123.c:check_fatal_output():334] error: out123 error 3: failure loading driver module

checked systemd bluealsa:

$ systemctl status bluealsa.service
● bluealsa.service - BlueALSA service
     Loaded: loaded (/lib/systemd/system/bluealsa.service; enabled; preset: enabled)
     Active: active (running) since Wed 2024-04-17 20:34:08 UTC; 6min ago
       Docs: man:bluealsa(8)
   Main PID: 531 (bluealsa)
      Tasks: 4 (limit: 380)
        CPU: 376ms
     CGroup: /system.slice/bluealsa.service
             └─531 /usr/bin/bluealsa -S -p a2dp-source -p a2dp-sink

Apr 17 20:34:08 rpi2w systemd[1]: Starting bluealsa.service - BlueALSA service...
Apr 17 20:34:08 rpi2w systemd[1]: Started bluealsa.service - BlueALSA service

checked pairing & trusting:

$ bluetoothctl
Agent registered
[CHG] Controller B8:27:EB:DE:B9:12 Pairable: yes
[bluetooth]# power on
Changing power on succeeded
[bluetooth]# devices
Device B8:F6:53:9B:1A:97 JBL Flip 5
[bluetooth]# devices Paired
Device B8:F6:53:9B:1A:97 JBL Flip 5
[bluetooth]# devices Trusted
Device B8:F6:53:9B:1A:97 JBL Flip 5

Tried again after "connecting" in bluetoothctl:

[bluetooth]# connect B8:F6:53:9B:1A:97
Attempting to connect to B8:F6:53:9B:1A:97
[CHG] Device B8:F6:53:9B:1A:97 Connected: yes
[NEW] Endpoint /org/bluez/hci0/dev_B8_F6_53_9B_1A_97/sep1
[NEW] Endpoint /org/bluez/hci0/dev_B8_F6_53_9B_1A_97/sep2
[NEW] Transport /org/bluez/hci0/dev_B8_F6_53_9B_1A_97/sep1/fd0
Connection successful
[NEW] Player /org/bluez/hci0/dev_B8_F6_53_9B_1A_97/player0 [default]
[CHG] Device B8:F6:53:9B:1A:97 ServicesResolved: yes
[CHG] Transport /org/bluez/hci0/dev_B8_F6_53_9B_1A_97/sep1/fd0 Volume: 0x0010 (16)
[JBL Flip 5]# quit

And now... SUCCESS!

$ nohup mpg123 -o alsa -a bluealsa --loop -1 rainstorm.mp3 &
[1] 835

Will this connect w/ bluetoothctl always be required to play music??

borine Apr 18, 2024
Collaborator

Will this connect w/ bluetoothctl always be required to play music??

Some speakers auto connect to a known device when the speaker is turned on, others do not. I've never used a JBL Flip so I do not know about yours. If your Pi was booted and bluealsa running before the JBL was powered on, and the JBL did not connect when it was turned on, then I guess it does not auto connect.

You can connect with a one-liner as

bluetoothctl connect B8:F6:53:9B:1A:97

graham8 Apr 18, 2024

My Flip 3 reconnects just fine.

borine Apr 18, 2024
Collaborator

My Flip 3 reconnects just fine.

thanks @graham8 : Then I guess the Flip 5 probably does try to connect also. Two possible reasons why it might fail in this case:

bluealsa was not running at the time that the Flip was turned on. Generally devices only try once on power up, they do not repeat the attempt if it fails.
The Flip connected to some other device that it is paired with - possibly a nearby mobile phone.

borine · 2024-04-18T12:16:54Z

borine
Apr 18, 2024
Collaborator

I don't like the idea of using nohup. That command is for starting long-running applications from a login shell - but surely you don't really intend to have to login to start this thing?

I've put together a simple non-interactive solution as a demonstration, based on systemd and using bluealsa-cli, that is active as soon as the pi is booted, and automatically plays the rainstorm sound whenever a bluetooth speaker is connected. (I know I previously suggested you would not need bluealsa-cli, so apologies for that). I've avoided hard-coding the speaker bt address so you can use it with any speaker. Hopefully this will give you a starting point from which to develop; you can modify it to suit your precise requirements.

If you are not using the "pi" account, then change the path to the rainstorm.mp3 file in the bash script mpg123 command, and the User= directive in the systemd service file. Make sure the chosen user is a member of the audio group in order to be able to use bluetooth audio.

Create the following 2 files:

/usr/local/bin/rainstorm

#!/bin/bash
exec &>/dev/null
for device in $(/usr/bin/bluetoothctl devices Paired | /usr/bin/sed -n 's/^Device \([^ ]*\).*$/\1/p')
do
	/usr/bin/bluealsa-cli list-pcms | grep 'a2dpsrc/sink$' && break
	if /usr/bin/bluetoothctl info "$device" | /usr/bin/grep -i 0000110b ; then
		/usr/bin/bluetoothctl connect "$device"
	fi
done
while true; do
	/usr/bin/mpg123 -o alsa -a bluealsa --quiet --no-control --loop -1 /home/pi/rainstorm.mp3
	/usr/bin/grep -q -m 1 '^PCMAdded.*a2dp.*sink' <(/usr/bin/bluealsa-cli monitor)
done

Make the rainstorm script executable

sudo chmod a+x /usr/local/bin/rainstorm

/usr/local/lib/systemd/system/rainstorm.service

[Unit]
Description=Rainstorm audio service
Requires=bluealsa.service
After=bluealsa.service

[Service]
Type=simple
User=pi
Group=audio
ExecStart=/usr/local/bin/rainstorm

[Install]
WantedBy=bluetooth.target

Start the new service with:

sudo systemctl daemon-reload
sudo systemctl enable --now rainstorm.service

The rainstorm sound will play as soon as a bluetooth speaker is connected, and run continuously until the speaker is disconnected. It will start every time the pi is booted, so no login is necessary.

1 reply

seamusdemora Apr 18, 2024
Author

Yes... using nohup was the only way I could get mpg123 to "cooperate" by running in the background. And I really didn't intend to login to start it... my plan was (once I got everything "ironed out") to start mpg123 from a cron job: start it at 11PM & "kill" it at 8AM.

Running mpg123 continuously in the background was my approach to getting things "ironed out"; testing for anything that halted execution & interrupted the sound. While evaluating pipewire I noticed that it would sometimes run for days, but other times, on other platforms, it stopped randomly (or it seemed so to me). I never found what caused this.

And speaking of "random stops", when I came in this morning to see how things were going w/ bluez-alsa & mpg123, the music had stopped. Here's what I found:

ps -e | grep mpg123 showed it to still be running, but "disassociated" from the SSH pts I started it under; i.e.:

$ ps -e | grep mpg123
712 ?        00:04:04 mpg123

checked bluealsa... this looks "healthy" to me:

$ systemctl status bluealsa.service
● bluealsa.service - BlueALSA service
     Loaded: loaded (/lib/systemd/system/bluealsa.service; enabled; preset: enabled)
     Active: active (running) since Thu 2024-04-18 05:59:08 UTC; 6h ago
       Docs: man:bluealsa(8)
   Main PID: 529 (bluealsa)
      Tasks: 6 (limit: 380)
        CPU: 2min 10.432s
     CGroup: /system.slice/bluealsa.service
             └─529 /usr/bin/bluealsa -S -p a2dp-source -p a2dp-sink

Apr 18 05:59:07 rpi2w systemd[1]: Starting bluealsa.service - BlueALSA service...
Apr 18 05:59:08 rpi2w systemd[1]: Started bluealsa.service - BlueALSA service.

checked w/ bluetoothctl... this also looked "healthy":

$ bluetoothctl
[JBL Flip 5]# power on
Changing power on succeeded
[JBL Flip 5]# devices Paired
Device B8:F6:53:9B:1A:97 JBL Flip 5
[JBL Flip 5]# devices Trusted
Device B8:F6:53:9B:1A:97 JBL Flip 5
[JBL Flip 5]# devices Connected
Device B8:F6:53:9B:1A:97 JBL Flip 5
[JBL Flip 5]# exit

but when I tried to re-start mpg123... does not look "healthy":

$ mpg123 -o alsa -a bluealsa rainstorm.mp3
High Performance MPEG 1.0/2.0/2.5 Audio Player for Layers 1, 2 and 3
	version 1.31.2; written and copyright by Michael Hipp and others
	free software (LGPL) without any warranty but with best wishes
ALSA lib ../../../src/asound/bluealsa-pcm.c:1477:(_snd_pcm_bluealsa_open) Couldn't get BlueALSA PCM: PCM not found
[src/libout123/modules/alsa.c:open_alsa():181] error: cannot open device bluealsa
[src/libout123/libout123.c:check_output_module():947] error: Module 'alsa' device open failed.
[src/libout123/libout123.c:out123_open():439] error: Found no driver out of [alsa] working with device bluealsa.
main: [src/mpg123.c:check_fatal_output():334] error: out123 error 3: failure loading driver module

And so, I'm unsure what caused this. A reboot brought everything "back to normal/good"; including an "automatic connect" between my RPi Zero 2W and the JBL Flip 5. Re-started mpg123 & it's still playing...

A coupla' things:

I am not wedded to mpg123... if you think there's a better/more reliable player I'm happy to try it.
Read some things last night that suggest perhaps 64-bit bookworm may not be "optimal" for RPi Zero 2W. I'll drop back to either 32-bit bookworm or 64-bit bullseye once I get a clear answer to a question I've posted at the RPi site.
I'm also going to try your systemd suggestion... I'm not proficient w/ systemd, but I think it will accommodate the "start at 11PM & stop at 8AM" objective. And re-building to add bluealsa-cli is not a problem... the first build went quite well, and didn't even take that long :)

Any other guidance is muchly appreciated

seamusdemora · 2024-04-18T20:08:50Z

seamusdemora
Apr 18, 2024
Author

The rainstorm sound will play as soon as a bluetooth speaker is connected, and run continuously until the speaker is disconnected. It will start every time the pi is booted, so no login is necessary.

Very cool!

I've rebuilt w/ the bluealsa-cli option & copied/pasted your script & unit file in the correct locations. Scheduling the start and stop for playing the rainstorm track looks like something I might be able to handle w/ my meager systemd skills (using Option B from here).

In the meantime, I'm running your script from cron - b/c it's faster/easier. Here's what I've added to the root crontab to start playing at 10:30 PM, and stop playing at 7:30 AM (note I keep my RPis sync'd to UTC) :

30 3 * * * /usr/local/bin/rainstorm >> /home/pi/rainstormlog.txt 2>&1
30 12 * * * /usr/bin/pkill rainstorm && /usr/bin/pkill mpg123 >> /home/pi/rainstormlog.txt 2>&1

6 replies

borine Apr 22, 2024
Collaborator

I really think that this failure has nothing to do with bluealsa or mpg123; there is some system event at play here, and so the answer is more likely to be found in the system logs. Perhaps a power-saving mode is kicking in? I know this can be problem for wifi with the RPiOS lite image - I put the following in /etc/rc.local

iw wlan0 set power_save off

but I do not know if this makes any difference to bluetooth.

seamusdemora Apr 22, 2024
Author

hmm... Thanks - I'll check this out & let you know what I find.

Would it make sense in this case to use bluetoothctl to check if the speaker is connected? i.e. something like:

if [ bluetoothctl devices Connected != "Device B8:F6:53:9B:1A:97 JBL Flip 5" ] ; then 
    < attempt to connect >
fi

borine Apr 22, 2024
Collaborator

Your shell syntax needs some work, but in principle you could do that if you prefer. But beware that bluetoothctl reports a device as connected so long as at least one service is connected, so in general it cannot guarantee that A2DP is connected. In your case that may not matter; perhaps the JBL will disconnect any other services if A2DP fails, I can't be sure because I don't have one. My aim was to avoid any specific bluetooth address, and allow the script to use any A2DP speaker that happens to be connected. Of course that may be a completely wrong approach for your scenario. Also the script was written without any time limits in mind, so it may well be possible to make changes to optimize it for use with systemd timers or cron. I'm not offering free consultancy for that though 😄

seamusdemora Apr 23, 2024
Author

I'm seeing a new "condition" since yesterday in the systemd status for bluealsa:

$ systemctl status bluealsa.service
● bluealsa.service - BlueALSA service
     Loaded: loaded (/lib/systemd/system/bluealsa.service; enabled; preset: enabled)
     Active: active (running) since Tue 2024-04-23 02:12:23 UTC; 25min ago
       Docs: man:bluealsa(8)
   Main PID: 526 (bluealsa)
      Tasks: 5 (limit: 380)
        CPU: 397ms
     CGroup: /system.slice/bluealsa.service
             └─526 /usr/bin/bluealsa -S -p a2dp-source -p a2dp-sink

Apr 23 02:12:22 rpi2w systemd[1]: Starting bluealsa.service - BlueALSA service...
Apr 23 02:12:23 rpi2w systemd[1]: Started bluealsa.service - BlueALSA service.
Apr 23 02:12:23 rpi2w bluealsa[526]: Couldn't get HCI version: Network is down

The last line: "Network is down". This was run shortly after a reboot, and during the time when the music is not playing. AFAIK, I've made no changes to my system... any idea what's causing this?

arkq Apr 23, 2024
Maintainer

Couldn't get HCI version: Network is down

In most cases this warning log is not harmful. It might pop out in cases when BlueALSA service starts before the HCI is UP. In your case it will do absolutely nothing. However, it might affect cases when one is using mSBC with HFP. Then, BlueALSA might not be able to determine whether local HCI interface can support mSBC.

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Building for a very lightweight platform? #695

seamusdemora Apr 16, 2024

Replies: 3 comments · 18 replies

borine Apr 16, 2024 Collaborator

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seamusdemora Apr 17, 2024 Author

THE ISSUE DESCRIBED BELOW HAS BEEN RESOLVED, BUT SEE QUESTION AT END OF REPLY

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