Ubuntu Focal Desktop

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1 Work with Ubuntu 20.04 (Focal) Desktop

1.1 Introduction to Ubuntu 20.04 Desktop

Ubuntu 20.04 Desktop has the following features：

• Base on Xorg, using LXQT as the desktop environment;
  
• SDDM is the default display manager;
  
• Mali GPU-based OpenGL ES support;
  
• Support Rockhip MPP video hard coding and hard decoding;
  
• Pre-installed mpv, support video hardware decoding;
  

1.2 Account & Password

Regular Account:
    User Name: pi
    Password: pi

Root:
    User Name: root
    Password: fa

1.3 Turn off auto-sleep and screen saver

sed -i 's/enableIdlenessWatcher=true/enableIdlenessWatcher=false/g' .config/lxqt/lxqt-powermanagement.conf
echo "mode:           off" > ~/.xscreensaver
sudo reboot

1.4 Set up auto login

Create dir and file:

sudo mkdir /etc/sddm.conf.d
sudo vim /etc/sddm.conf.d/autologin

The contents of the autologin file：

[Autologin]
User=pi
Session=lxqt.desktop
Relogin=false

Reboot.

1.5 Test Video Playback

• mpv

mpv ~/Videos/demo.mp4

• GStreamer Command Line

gst-play-1.0 ~/Videos/demo.mp4 --videosink=xvimagesink

For more details, please search and refer to the official documentation <<rockchip_user_guide_linux_gstreamer_en.pdf>>.

1.6 Audio Settings

1.6.1 Switching Audio Output Channel

To switch the audio output channel, go to "System Tools" -> "Qterminal"，enter the following command in the terminal to check available audio output channels:

export XDG_RUNTIME_DIR=/run/user/1000
pactl list sinks short

On the NanoPC-T6, the results appear as follows. The string beginning with alsa_output in the second column is the value we will use:

0       alsa_output.platform-dp0-sound.stereo-fallback  module-alsa-card.c      s16le 2ch 44100Hz       SUSPENDED
1       alsa_output.platform-hdmi0-sound.stereo-fallback        module-alsa-card.c      s16le 2ch 48000Hz       SUSPENDED
2       alsa_output.platform-hdmi1-sound.stereo-fallback        module-alsa-card.c      s16le 2ch 44100Hz       SUSPENDED
3       alsa_output.platform-rt5616-sound.multichannel-output   module-alsa-card.c      s16le 2ch 44100Hz       SUSPENDED

Use an editor to modify the PulseAudio configuration file:

sudo vim /etc/pulse/default.pa

If you need to set the audio output to HDMI1, replace the following line at the end of the file:

set-default-sink alsa_output.platform-hdmi0-sound.stereo-fallback

with:

set-default-sink alsa_output.platform-hdmi1-sound.stereo-fallback

Save the file and restart the system for the changes to take effect, or restart the PulseAudio service:

pulseaudio -k
pulseaudio --start

1.6.2 Multi-Device Audio Output

Edit the PulseAudio configuration file:

sudo vim /etc/pulse/default.pa

Scroll to the end of the file, delete any line that starts with set-default-sink, and add the following lines at the end:

load-module module-combine-sink sink_name=combined slaves=alsa_output.platform-hdmi0-sound.stereo-fallback,alsa_output.platform-hdmi1-sound.stereo-fallback
set-default-sink combined

Restart the system. With this configuration, audio will output simultaneously to both the HDMI0 and HDMI1 interfaces.