Music Player

1. Start setting up audio working on Raspberry Pi 3 with Raspbian

• For the September 2019 version of Raspbian Buster, ALSA and its dependencies are pre-installed with the operating system.
• Load the sound driver and check if it is loaded:

  sudo modprobe snd-bcm2835
  sudo lsmod | grep 2835

• Select the output device for sound (0 = default/auo, 1 = jack 3.5, 2 = HDMI)

  sudo amixer cset numid=3 1

• Open terminal and test ALSA working

  aplay /usr/share/sounds/alsa/Front_Center.wav

• It is required to have the file asound.conf to set up output hardware/soundcard properly.

  sudo nano /etc/asound.conf

• Copy and paste the following code and save it:

pcm.!default {
	type plug
	slave {
		pcm "hw:1,0"
	}
}
ctl.!default {
	type hw           
	card 1
}

2. mpg123 library

• This music player project is built based on the library mpg123 and libout123
• Install libmpg123, you may need to install package mpg123 separately if mpg123 command does not work.

  sudo apt-get install libmpg123-dev

• And:

  sudo apt-get install mpg123

• In latest release, libout123 automatically installed with mpg123, if libout123(out123.so) is lacked in any older version, install libout123 separately by following this instruction

3. Test mpg123

• Normally, simply use mpg123 command:

  mpg123 file_name.mp3

• Or use remote control interface, you can play file by commands

  mpg123 -R

• For remote interface commands, check this link
• If mpg123 does not work, it could be the error of picking up wrong output port, try this command by using ALSA to specify output hardware:

  aplay -l mpg123 -a hw:1,0 file_name.mp3

4. Compile and run our code

• Simply run

  make
  ./a.out