GKDV - Useless proofs of concepts ¯\_(ツ)_/¯

Useless proofs of concepts ¯\_(ツ)_/¯

How to listen an audio cd to your chromecast installation?

Written on April 3, 2019

Using a raspberry, an usb cd reader, a wifi dongle… Stream an audio cd to a multi-chromecasts room !

How to ?

What you need

What will we use

  • An icecast2 server
  • ffmpeg
  • python3 with pychromecast
  • udev rule

Global instructions

We will use an icecast server, to install it:

$ sudo apt-get install icecast2

Icecast2 server will broadcast the audio feed

And we need ffmpeg, which will stream audio cd to icecast2 feed:

$ sudo apt-get install ffmpeg

Some configuration, for icecast2: edit the /etc/icecast2/icecast.xml file, and check the authentication part:

    <authentication>
        <!-- Sources log in with username 'source' -->
        <source-password>YOUR_PASSWORD</source-password>
        <!-- Relays log in with username 'relay' -->
        <relay-password>YOUR_PASSWORD</relay-password>

        <!-- Admin logs in with the username given below -->
        <admin-user>admin</admin-user>
        <admin-password>YOUR_PASSWORD</admin-password>
    </authentication>

And the hostname and socket part:

<hostname>localhost</hostname>

<!-- You may have multiple <listener> elements -->
<listen-socket>
    <port>8000</port>
    <!-- <bind-address>127.0.0.1</bind-address> -->
    <!-- <shoutcast-mount>/stream</shoutcast-mount> -->
</listen-socket>

You can see the full config file in the Chromecast-audio-cd-caster repo

To stream using ffmpeg, simply use:

/usr/bin/ffmpeg  -f libcdio -ss 0 -i /dev/cdrom -acodec libmp3lame -ab 48k -bufsize 15 -ac 1 -content_type audio/mpeg -f mp3  icecast://source:YOUR_PASSWORD@192.168.0.31:8000/raspi

(Don’t forget to replace 192.168.0.31 by your raspberry pi local ip)

You have now a feed readable from http://192.168.0.31:8000/raspi

How to cast?

To cast what you want to a chromecast, have a look on Pychromecast Of course, you need python3:

$ sudo apt-get install python3

And a tiny python script:

import time
import pychromecast
import urllib.request

stream_url = 'http://192.168.0.31:8000/raspi'
chromecasts = pychromecast.get_chromecasts()
cast = next(cc for cc in chromecasts if cc.device.friendly_name == "Salon")
cast.wait()
print(cast.device)
print(cast.status)
mc = cast.media_controller
while urllib.request.urlopen(stream_url).getcode() != 200:
    print('Waiting for stream up')
    time.sleep(1)

mc.play_media(stream_url, 'audio/mp3')
mc.block_until_active()
print(mc.status)
mc.play()

And … it’s a kind of magic:

$ /usr/bin/ffmpeg  -f libcdio -ss 0 -i /dev/cdrom -acodec libmp3lame -ab 48k -bufsize 15 -ac 1 -content_type audio/mpeg -f mp3  icecast://source:SOURCE_PASSWORD@192.168.0.31:8000/raspi & /usr/bin/python3 /home/pi/audio/cast.py

Bonus: autostart on cd insertion

We will use an udev rule, for example in a /etc/udev/rules.d/99-cd-audio-processing.rules rule:

SUBSYSTEM=="block", KERNEL=="sr0", ACTION=="change", RUN+="/home/pi/audio/start-cd.sh &"

Reboot, and you’re ready :)

See sources on Chromecast-audio-cd-caster repo

To conclude…

However, it’s a bit long to start reading, and all my music is already uploaded on my google music account, so … useless ¯\(ツ)