Libreelec 10.0.1 on RPi-4B : Simultanous output to HDMI and Bluetooth Box?

doejohn · December 31, 2021 at 4:04 PM

Hello all,

I am trying to get audio output onto HDMI and a Bluetooth box working simultanously.

This wiki entry suggests that this should be possible with the pulseaudio module-combine-sink

Unfortunately, I have a hard time to find my audio sinks. The sinks I am interested in are listed by Kodi as:

Code

ALSA: Default Audio Device ()
PULSE: Default, Bluetooth Audio (PULSEAUDIO)

But neither pactl nor amixer shows me those two devices:

Code

kodi-rpi4:~ # pactl list short sinks
4       auto_null       module-null-sink.c      s16le 2ch 44100Hz       SUSPENDED
kodi-rpi4:~ # pactl info
Server String: /var/run/pulse/native
Library Protocol Version: 34
Server Protocol Version: 34
Is Local: yes
Client Index: 33
Tile Size: 65496
User Name: root
Host Name: kodi-rpi4
Server Name: pulseaudio
Server Version: 14.2
Default Sample Specification: s16le 2ch 44100Hz
Default Channel Map: front-left,front-right
Default Sink: auto_null
Default Source: auto_null.monitor
Cookie: 6087:a029
kodi-rpi4:~ # aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0

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In addition, I get:

Code

kodi-rpi4:~ # pacmd list-cards
No PulseAudio daemon running, or not running as session daemon.
kodi-rpi4:~ # export PULSE_RUNTIME_PATH=/run/pulse
kodi-rpi4:~ # pacmd list-cards
0 card(s) available.

Nevertheless, after executing

Code

kodi-rpi4:~ # pacmd load-module module-combine-sink sink_name=combined

a new device appears in Kodi, called

Code

PULSE: Simultanous output to Anker SoudCore (PULSEAUDIO)

When I select this device, my Bluetooth box plays fine. So the module-combine-sink basically seems to work. But how do I find the name of the HDMI sink so that I can add it to the combined sink?

What's more, all those settings don't change when I change outputs in Kodi.

https://kodi.wiki/view/PulseAudio says, it is not possible to have ALSA and Pulseaudio at the same time. But Kodi shows me ALSA devices as well as Pulseaudio devices. Can anybody elaborate on this? What is installed by default in a libreelec install on RPi 4B?

Thanks in Advance!

doejohn · January 1, 2022 at 11:58 AM

Digging through pulseaudio, I found that

Code

pactl module-load module-udev-detect

should detect alsa devices and make them available to pulseaudio. But for some reason, this command fails to detect those devices:

Code

kodi-rpi4:~ # aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
kodi-rpi4:~ # pactl unload-module module-udev-detect
kodi-rpi4:~ # pactl load-module module-udev-detect
45
kodi-rpi4:~ # pactl list short cards
1       bluez_card.A4_77_58_02_93_FB    module-bluez5-device.c
kodi-rpi4:~ #

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Any idea why this command won't find the alsa cards?

Is there any way to debug pulseaudio?

doejohn · January 1, 2022 at 1:46 PM

Got it (almost) working now.

Problem was, that module-udev-detect can be loaded only once at startup. So executing

Code

echo "pactl load-module module-udev-detect" >> /storage/.config/autostart.sh

makes alsa sinks available after reboot.

After that, executing

Code

pactl load-module module-combine-sink slaves=alsa_output.0.hdmi-stereo,bluez_sink.A4_77_58_02_93_FB.a2dp_sink

on the command line makes the device for simultanous output available to Kodi. Works fine so far.

Problem is, this last command won't work from autostart.sh to make this simultanous sink available after boot because the bluetooth speaker is not available at boot time.

Journalctl says:

Code

Jan 01 14:18:06 kodi-rpi4 pulseaudio[352]: E: [pulseaudio] module-combine-sink.c: Invalid slave sink 'bluez_sink.A4_77_58_02_93_FB.a2dp_sink'
Jan 01 14:18:06 kodi-rpi4 pulseaudio[352]: E: [pulseaudio] module.c: Failed to load module "module-combine-sink" (argument: "slaves=alsa_output.0.hdmi-stereo,bluez_sink.A4_77_58_02_93_FB.a2dp_sink"): initialization failed.
Jan 01 14:18:18 kodi-rpi4 pulseaudio[352]: E: [pulseaudio] module-combine-sink.c: failed to parse module arguments
Jan 01 14:18:18 kodi-rpi4 pulseaudio[352]: E: [pulseaudio] module.c: Failed to load module "module-combine-sink" (argument: "sink_name=combined alsa_output.0.hdmi-stereo"): initialization failed.

the bluetooth sink is created only after I switch the bluetooth speaker off and on again.

So the question now is: is it possible to create the bluetoosh sink even before the connection to the actual device has been made?

Ultraproton · January 18, 2022 at 9:29 AM

You can try:

systemctl start bluetooth

(sleep 1; bluetoothctl connect "00_1B_66_CE_7F_96")

before code in /storage/.config/autostart.sh

Ofcourse change string to your device

thedogg · October 26, 2022 at 4:58 PM

Does it work for you? I want to use hdmi pass through and bloototh in the same time. Is it possible?

xhbl · November 5, 2022 at 2:59 AM

Try my kodi dualaudio project. I have a LibreELEC Generic PC version compiled. For Raspberry Pi, you can simply get the source code and compile by your own.

Please visit my project page:

https://github.com/xhbl/LibreELEC_dualaudio/

For more information, please refer to the thread I posted here and in Kodi Forum

Thread

Simultaneous Audio Output

Hi, I developed Dual Audio output support for Kodi (see the post in Kodi forum) and I think LibreELEC is a more practical build for most of the media player hardware. I start a post here mainly for getting support for building more ready-to-use releases for different hardware devices running LibreELEC.

Now I've built Generic/RPi version for testing purpose. I have an Intel NUC so that I can run this for test. I saw some demands that request this feature on other devices, because of limited time…

xhbl

November 5, 2022 at 9:15 PM

[Project] Dual Audio Output support (Matrix/Krypton/Jarvis/Isengard/Helix/Gotham/...)

b22222222222 · November 15, 2022 at 10:11 PM

it works for me

my /storage/.config/autostart.sh :

pactl load-module module-udev-detect

pactl load-module module-combine-sink slaves=alsa_output.0.hdmi-stereo,alsa_output.3.iec958-stereo

however I have 2 problems

1) playing video create sometimes echo artifacts (crackling) on hdmi output

2) playing spotify plugin librespot? causes lagging / pitch during palyback

Not sure if this is pulseaudio problem or HW is just too weak to send audio to 2 sinks.. (RPi3)

anyone knows?b

VLouis · November 16, 2022 at 7:14 AM

Quote from b22222222222

Not sure if this is pulseaudio problem or HW is just too weak to send audio to 2 sinks.. (RPi3)

anyone knows?

I had almost same "result" when tried to get working the HDMI and DAC sound on my RPi3.

The "echo" problem you have probably because the hdmi and the bluetooth have different delay in sound processing, I had too when tried to use same setup. Because I didn't need simultaneous audio (HDMI for video, DAC for music/net-radio), I dropped the pulse-audio and using the "Audio profiles" addon. That able to auto switch the audio output for different types of media.

b22222222222 · November 16, 2022 at 8:42 PM

Hi,

Actually my case is same as yours HDMI and DAC (Hifiberry) RPi3..

The addon is interesting, I will check it out.

Nevertheless Did I undersand right that you did not solved the pulseaudio issue at all? Or you at least found what causes the "echo"?

Anybody else had /resolved the same issue?

VLouis · November 17, 2022 at 8:27 AM

Quote from b22222222222

Hi,
Actually my case is same as yours HDMI and DAC (Hifiberry) RPi3..
The addon is interesting, I will check it out.
Nevertheless Did I undersand right that you did not solved the pulseaudio issue at all? Or you at least found what causes the "echo"?
Anybody else had /resolved the same issue?

First of all, to be clear, the "Audio Profiles" addon don't have option for simultaneous audio. And if no simultaneous audio... no echo.

I'm using without pulse-audio, only with the default alsa sound and enabled in the config.txt the hifiberry module. I set the addon to change the sound output to DAC for audio type media (listening music) and to HDMI for video. Also the addon can be set to toggle the sound outputswith a remote button (ex for youtube, never tried...).

Basically I wanted to be able to listen my favorite internet radio channel using the better quality DAC output, without to be necessary to start the TV, so I reprogrammed a remote button (remote.xml) to start the music, and the addon automatically switch the sound output to DAC.

Mayoru · April 24, 2024 at 9:11 PM

Thanks a lot for this, I searched really long and now I found my solution thanks to you:
~/.config/autostart.sh

Code

(
pactl load-module module-udev-detect
pactl load-module module-combine-sink
)&

Mayoru · April 28, 2024 at 2:34 PM

A strange Problem. On HDMi I have crackls in the output. Bluetooth is without any problems. At first I assumed, that it works better even if I disconnect the bluetooth device.

VLouis · April 29, 2024 at 10:23 AM

Quote from Mayoru

A strange Problem. On HDMi I have crackls in the output. Bluetooth is without any problems. At first I assumed, that it works better even if I disconnect the bluetooth device.

I lost a lot of time in the past for that "simultanous audio output", without to find a stable solution without issues. Till I discovered, I didn't want a real simoultaous audio (never used two outputs simultanous). Basically I wanted sound though HDMI for video files and I2S (hifiberry) for music (mostly internet radio). And for this the "Audio Profiles" addon is perfect for me. With a bit of work in the addon settings, it's able to change automatically the audio output based on media type.

Mayoru · May 12, 2024 at 7:30 AM

In my opinian a job that Kodi should do and offer in the settings.

VLouis · May 12, 2024 at 9:06 AM

I'm just wondering... in the case of this "simultanous audio output", exist users who really using the audio output in that way? To hear the sound from TV (HDMI) and amplifier or bluetooth spekers in the same time? I tried that and because of the delay differences, the result was a "strange" sound with some kind of "echo".

Don't mean me wrong, if somebody really want it, search for possible solution, experiment, learn meantime... but I think exist a reason why "Kodi don't do and don't offer in the settings" such option.

Mayoru · May 13, 2024 at 9:42 PM

I do not use it in the same room. I mostly use my Kodi as radio. Therefor I use a Bluetooth speaker in the kitchen and in the garden. In such a case an Echo is not important. TV is only a third prioirity. (second is the tv as Diashow)

VLouis · May 14, 2024 at 7:04 AM

Quote from Mayoru

I do not use it in the same room. I mostly use my Kodi as radio. Therefor I use a Bluetooth speaker in the kitchen and in the garden. In such a case an Echo is not important. TV is only a third prioirity. (second is the tv as Diashow)

Is possible to use two bluetooth speakers at the same time? Don't know if the bluetooth is capable for such a thing.

I'm using internet radio in the garden too, for this I have a simple solution, an old smart-phone without sim, without account, only wifi and an app for music (with ability to play net stream - ex. AIMP - android). I like to find new purpose for old smart-phones, another one is used as a perfect desk clock...

Mayoru · March 23, 2025 at 8:09 PM

Meanwhile the warm Days come again. And I tested it again.

Now, it is reverse. My TV plays without any Problems but my Bluetoth speaker now cracks a lot and the quality move alot between low quality and high quality. Not possible to hear anything.

Libreelec 10.0.1 on RPi-4B : Simultanous output to HDMI and Bluetooth Box?

Simultaneous Audio Output

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