Alternative Audioplayer

Most audioplayer solutions out there are images for a raspberry pi to use the pi exclusively.

There are use cases though where one wants to do more with a single RPI or use other platforms like an odroid or Asus tinker board.

A good base to start is a dietpi image. But also existing systems with other is could be used.

Dietpi

I used to customise fresh os images with a couple of ansible scripts. This became obsolet when i discovered dietpi. Dietpi provides os images for every SBC platform i care about and then some. Dietpi then provides a terminal based interface for system configuration and maintainance. Other than with many ready made audio distributions it is easy to keep the system up to date and install security patches.

Network

Since almost everything relies on it, it makes sense to setup the network first.

• wired ethernet
  if one is so lucky as to have wired ethernet available, just plugin a network cable and that is the network setup.

• Wlan manual setup
  Dietpi provides an easy to use terminal interface to set up WiFi. Either do a temporary wired ethernet connect and then ssh into the system or connect a screen and a keyboard. Login with user: root and password: dietpi Run dietpi-config

• Wlan scripted setup
  In the file /boot/dietpi-wifi.txt up to 4 WiFi credentials can be configured. On dietpi images for raspberry is a Fat32 partition that holds the /boot directory. This partition can be mounted with any OS (Windows, Mac, Linux)
  On the dietpi image for the tinkerboard is only one extfs4 partition that contains the /boot directory. This makes things a bit more complicated. Since we need write access the ext4 partition is best mounted on a linux machine. If a linux machine is not available it is best to run a virtual machine like Virtualbox. It is necessary to enable the USB Port in settings while the instance is not running. Setting up the instance can be done in the virtualbox gui or with vagrant on the cmdline.
  vagrant init ubuntu/focal64
  vagrant up
  vagrant ssh
  once we are in the virtual instance we need to mount the ext4 partition in the usb slot. First we need to find out which device we want o mount.
  sudo fdisk -l
  When we identified /dev/sdc1 as the partition in question we can mount with
  sudo mount /dev/sdc1 /mnt
  Now we can edit /mnt/boot/dietpi-wifi.txt. After saving the changes dont forget to umount the partition before removing the sd-card.

General Software

There is dietpi-software to provide a  cmd line interface to install additional software.

If you find yourself doing this often, you might want to look into scripting the setup. This is done in /boot/dietpi.txt.

AUTO_SETUP_ACCEPT_LICENSE=1
AUTO_SETUP_KEYBOARD_LAYOUT=de
AUTO_SETUP_TIMEZONE=Europe/Berlin
AUTO_SETUP_NET_ETHERNET_ENABLED=1
AUTO_SETUP_NET_WIFI_ENABLED=1
AUTO_SETUP_BOOT_WAIT_FOR_NETWORK=0
AUTO_SETUP_SSH_SERVER_INDEX=-2
AUTO_SETUP_AUTOSTART_TARGET_INDEX=11
AUTO_SETUP_AUTOMATED=1
#AUTO_SETUP_INSTALL_SOFTWARE_ID=23
AUTO_SETUP_INSTALL_SOFTWARE_ID=5
AUTO_SETUP_INSTALL_SOFTWARE_ID=7
AUTO_SETUP_INSTALL_SOFTWARE_ID=17
AUTO_SETUP_INSTALL_SOFTWARE_ID=20
AUTO_SETUP_INSTALL_SOFTWARE_ID=36
AUTO_SETUP_INSTALL_SOFTWARE_ID=37
AUTO_SETUP_INSTALL_SOFTWARE_ID=113
AUTO_SETUP_INSTALL_SOFTWARE_ID=130
AUTO_SETUP_INSTALL_SOFTWARE_ID=134
AUTO_SETUP_INSTALL_SOFTWARE_ID=141
AUTO_SETUP_INSTALL_SOFTWARE_ID=162
AUTO_SETUP_INSTALL_SOFTWARE_ID=190

CONFIG_SOUNDCARD=asus-tb-analogue

SOFTWARE_CHROMIUM_RES_X=1280

SOFTWARE_CHROMIUM_RES_Y=720

SOFTWARE_CHROMIUM_AUTOSTART_URL=https://127.0.0.1:6680/

To work around a problem with docker we add this line to /boot/armbianEnv.txt

systemd.unified_cgroup_hierarchy=0

Setting up the command line

There is a little left to be done on the commandline. First lets create some comfort to ssh. On laptop or workstation:

ssh-copy-id root@192.168.2.114

edit ~/.ssh/config

host tinker

    Hostname 192.168.2.114

    User root

Now we can ssh into the tinkerboard like so:

ssh tinker

With long running installations it is best to use tmux. Yet i have not found a package with dietpi. So we install it with apt.

sudo apt install tmux

Lets test whether the alsa devices are there:

aplay -L

Now lets CHeck if we can play some sound through the device.

speaker-test -c 2 -D hw:CARD=OnBoard,DEV=2

Docker Compose

A great way to isolate the player setup from the rest of the system is to use a docker container.
This is a mediaplayer setup using mopidy and rompr.
Create a docker-compose.yml file:

version: "3"
services:
  mopidy:
    image: rawdlite/mopidy
    container_name: mopidy
    devices:
      - "/dev/snd"
    ports:
      - "6600:6600"
      - "6680:6680"
    restart: always
    volumes:
      - ~/.config/:/root/.config/
      - /data/music/:/data/music/
  mysql:
    image: linuxserver/mariadb
    restart: unless-stopped
    container_name: mysql
    environment:
      - PUID=1000
      - PGID=1000
      - MYSQL_ROOT_PASSWORD=b4FUk4mF>3As3aA
      - TZ=Europe/Berlin
      - MYSQL_DATABASE=romprdb
      - MYSQL_USER=rompr
      - MYSQL_PASSWORD=romprdbpass
    volumes:
      - ./db_config:/config
    ports:
      - "3306:3306"
  rompr:
    image: rawdlite/rompr
    container_name: rompr
    restart: always
    ports:
      - "80:80"

Now lets start the containers

docker-compose up -d

If this gets an error on the tinkerboard. Edit /boot/boot.scr
setenv bootargs "... systemd.unified_cgroup_hierarchy=0 ...
then
mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr

reboot and test with
cat /proc/cmdline

it should say systemd.unified_cgroup_hierarchy=0. Docker should now run. We can test this with

docker ps

Config Mopidy

Mopidy configfile is ~/.config/mopidy/mopidy.conf
[core]
max_tracklist_length = 5000
restore_state = true

[audio]
mixer = none
output = alsasink device="hw:CARD=OnBoard,DEV=2"

[file]
enabled = true
media_dirs =
  /data/music/music_data|MUSIC
follow_symlinks = true
metadata_timeout = 1000
excluded_file_extensions =
  .directory
  .html
  .jpeg
  .jpg
  .log
  .nfo
  .pdf
  .png
  .txt
  .zip
show_dotfiles = false

[softwaremixer]
enabled = false

[mpd]
enabled = true
hostname = ::
port = 6600

[http]
enabled = true
hostname = ::
port = 6680

To see how mopidy is doing:
docker logs mopidy

To see the effective configuration
docker exec -it mopidy mopidy config

Run Rompr

Browse to the ip of the tinder board. Setup Rompr. This gives an missing super privilege error.

docker exec -it mysql mysql -u root -p

Use password from docker-compose.yml file.
SET GLOBAL log_bin_trust_function_creators = 1;

Now rompr can use mysql. Now enter the ip of the tinder board in the field MPD SErver. And RompR should start. Other interfaces can be used through http://<ip address>:6680

This concludes the player setup for now.