Getting sound from jack with ALSA instead of PulseAudio

davidino

Goodmorning,
I'm using a Raspberrypi0-wifi connect to an audio board via I2S. The QT version is 5.12.0. I installed all the stuff that I can find on the net concerning this topic but still I cannot make the app to play the sound through the analog output. Here some information:

If I try to play a song with mpg123 program the sound comes correctly from the jack output.
Trying to print out the available audio devices with the following code:

QList<QAudioDeviceInfo> devices = QAudioDeviceInfo::availableDevices(QAudio::AudioOutput);
    foreach (QAudioDeviceInfo i, devices){
        qDebug()<<i.deviceName();
    }

I get the following:
"default"
"sysdefault:CARD=sndrpihifiberry"

With the command aplay -l, I get the following:
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi p]
Subdevices: 1/1
Subdevice #0: subdevice #0
My code consists in a MediaPlayer with playlist made in QML:

    MediaPlayer {
        id: playMusic
        autoLoad: true
        autoPlay: true
        playlist: Playlist { id:playerList; }
        Component.onCompleted: volumeMeter.initVolume(playMusic);
    }

For creating the image and the cross-compiling toolchain I used Yocto with b2qt.
Adding the following lines in local.conf:

PACKAGECONFIG_append_pn-qtmultimedia = " gstreamer alsa"
PACKAGECONFIG_append_pn-gstreamer1.0-plugins-ugly = "a52dec lame mad mpeg2dec x264" 
PACKAGECONFIG_remove_pn-qtmultimedia = " pulseaudio"
DISTRO_FEATURES_remove = " pulseaudio" 

IMAGE_INSTALL += "alsa-lib alsa-plugins alsa-utils alsa-state alsa-tools alsa-oss"
IMAGE_INSTALL += " \
	gst-meta-video \
	gst-plugins-base-app \
	gst-plugins-base \
	gst-plugins-good \
	gst-plugins-good-rtsp \
	gst-plugins-good-udp \
	gst-plugins-good-rtpmanager \
	gst-plugins-good-rtp \
	gst-plugins-good-video4linux2 \
	gstreamer1.0-plugins-good \
	gstreamer1.0-plugins-base \
	gstreamer1.0-plugins-ugly \
	gstreamer1.0-libav \
	gst-fluendo-mp3 \ 
"

I wonder if there are some libraries/plugins that can let qt to work with the analog audio. At the moment I have found installed libqtaudio_alsa.so and libasound.so,
May they be useful? And if yes, how should I use them?

Thank you.

Regards,
Davide Brunelli

davidino

Hello @MangoCat ,
thank you for your message. Actually it's different installing directly to the Raspberry than using Yocto, but for sure it can be useful.
At the end I sorted out, installing the following including pulseaudio (maybe several of all are unnecessary but I installed whatever I found on the net):

PACKAGECONFIG_append_pn-qtmultimedia = " gstreamer alsa"
PACKAGECONFIG_append_pn-gstreamer1.0-plugins-ugly = "a52dec lame mpeg2dec x264" 
#PACKAGECONFIG_remove_pn-qtmultimedia = " pulseaudio"
#DISTRO_FEATURES_remove = " pulseaudio" 

IMAGE_INSTALL += "alsa-lib alsa-plugins alsa-utils-speakertest alsa-utils alsa-state alsa-tools"

IMAGE_INSTALL += "\
	gstreamer1.0 \ 
        gstreamer1.0-plugins-base-meta \
	gstreamer1.0-plugins-good-meta \
        gstreamer1.0-plugins-bad-meta \
        gstreamer1.0-plugins-bad \
        gstreamer1.0-plugins-base-playback \
        gstreamer1.0-plugins-ugly-meta \	
	gst-meta-video \
	gst-plugins-base-app \
	gst-plugins-base \
	gst-plugins-good \
	gst-plugins-good-rtsp \
	gst-plugins-good-udp \
	gst-plugins-good-rtpmanager \
	gst-plugins-good-rtp \
	gst-plugins-good-video4linux2 \
	gstreamer1.0-plugins-good \
	gstreamer1.0-plugins-base \
	gstreamer1.0-plugins-ugly \
	gstreamer1.0-libav \
	gst-fluendo-mp3 \ 
"

DISTRO_FEATURES_append = " pulseaudio dbus"
IMAGE_INSTALL_append = " pulseaudio pulseaudio-server \
qtmultimedia qtmultimedia-plugins qtmultimedia-qmlplugins dbus pulseaudio-misc"
PACKAGECONFIG_append_pn-qtmultimedia = " pulseaudio"
#PACKAGECONFIG_pn-pulseaudio_append

Besides pulseaudio is called together with the main application, with the following bash script:

#!/bin/bash

sleep 10

# Maybe we can do a separate service
# forum.qt.io/topic/108039/unable-to-play-audio-on-embedded-device-using-pulseaudio-audi$
if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
     echo "Starting dbus"
     export $(dbus-launch)
fi

/usr/bin/pulseaudio -D --start

#/usr/bin/psplash

#Main application
/usr/bin/gallery-mobile

Hope it helps whoever is facing the same issue as mine.

Regards,
Davidino

MangoCat

I had your same problem, no output from QMediaPlayer on a RaspiZeroW with a Hifiberry-MiniAmp (same driver as their DAC) - solution at bottom.

This code works on my desktop system in both modes, but in the Rpi only in the mplayer mode:

void PlayController::play( QFileInfo fi )
{ if ( soundPlayer == 2 )
    { QMediaPlayer *player = new QMediaPlayer;
      player->setMedia(QUrl::fromLocalFile( fi.absoluteFilePath() ));
      // player->setVolume(50);
      player->play();
    }
   else
    QProcess::execute( "/usr/bin/mplayer", QStringList( fi.absoluteFilePath() ) );
}

I have installed:

sudo apt install qt5-default cmake qtcreator qtmultimedia5-dev libqt5multimedia5-plugins mpg321 lame pulseaudio

adding

sudo apt install gstreamer1.0-tools

did not help... of course, my aplay -l is the same as yours:

pi@blueberry:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi pcm5102a-hifi-0 [HifiBerry DAC HiFi pcm5102a-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

My Pi is setup with fresh Raspbian, which comes with Qt 5.11

Solved my issue with a:

sudo apt install gstreamer1.0-pulseaudio

hope this helps...

davidino

Hello @MangoCat ,
thank you for your message. Actually it's different installing directly to the Raspberry than using Yocto, but for sure it can be useful.
At the end I sorted out, installing the following including pulseaudio (maybe several of all are unnecessary but I installed whatever I found on the net):

PACKAGECONFIG_append_pn-qtmultimedia = " gstreamer alsa"
PACKAGECONFIG_append_pn-gstreamer1.0-plugins-ugly = "a52dec lame mpeg2dec x264" 
#PACKAGECONFIG_remove_pn-qtmultimedia = " pulseaudio"
#DISTRO_FEATURES_remove = " pulseaudio" 

IMAGE_INSTALL += "alsa-lib alsa-plugins alsa-utils-speakertest alsa-utils alsa-state alsa-tools"

IMAGE_INSTALL += "\
	gstreamer1.0 \ 
        gstreamer1.0-plugins-base-meta \
	gstreamer1.0-plugins-good-meta \
        gstreamer1.0-plugins-bad-meta \
        gstreamer1.0-plugins-bad \
        gstreamer1.0-plugins-base-playback \
        gstreamer1.0-plugins-ugly-meta \	
	gst-meta-video \
	gst-plugins-base-app \
	gst-plugins-base \
	gst-plugins-good \
	gst-plugins-good-rtsp \
	gst-plugins-good-udp \
	gst-plugins-good-rtpmanager \
	gst-plugins-good-rtp \
	gst-plugins-good-video4linux2 \
	gstreamer1.0-plugins-good \
	gstreamer1.0-plugins-base \
	gstreamer1.0-plugins-ugly \
	gstreamer1.0-libav \
	gst-fluendo-mp3 \ 
"

DISTRO_FEATURES_append = " pulseaudio dbus"
IMAGE_INSTALL_append = " pulseaudio pulseaudio-server \
qtmultimedia qtmultimedia-plugins qtmultimedia-qmlplugins dbus pulseaudio-misc"
PACKAGECONFIG_append_pn-qtmultimedia = " pulseaudio"
#PACKAGECONFIG_pn-pulseaudio_append

Besides pulseaudio is called together with the main application, with the following bash script:

#!/bin/bash

sleep 10

# Maybe we can do a separate service
# forum.qt.io/topic/108039/unable-to-play-audio-on-embedded-device-using-pulseaudio-audi$
if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
     echo "Starting dbus"
     export $(dbus-launch)
fi

/usr/bin/pulseaudio -D --start

#/usr/bin/psplash

#Main application
/usr/bin/gallery-mobile

Hope it helps whoever is facing the same issue as mine.

Regards,
Davidino