Month: October 2015

Hackspace Hat quick install (or: audio and video streaming from a Raspberry Pi to a remote or local WebRTC-compatible-browser)

I’ve been distracted by other things, but just in case it’s useful to anyone, here’s how to make a HackspaceHat with one-way streaming audio and video (i.e. audio and video streaming from a Pi to a remote server).

We’re now thinking about different ways of doing this, as we have been having lots of problems with ports, and we’re using WebRTC only to stream to a server, not peer-to-peer, and only one-way. But anyway. It’s easy and it mostly works.

This excellent article got me started – I added audio, and the remote server, plus the gstreamer commands have changed slightly.

You will need:

hsh_innards

Set up the Pi

This is how I do it on a Mac. Here are the official instructions.

diskutil list
diskutil unmountDisk /dev/diskn
sudo dd bs=1m if=~/Downloads/2015-05-05-raspbian-wheezy.img of=/dev/rdiskn

(where ‘n’ is the disk number from diskutil list, on mine, usually, ‘2’).

I’ve not tried this with jessie yet – no reason to think it wouldn’t work.

Then boot up the Pi and ssh in using network sharing and an ethernet cable, or use a keyboard and HDMI screen. Log in.

Finish the config and enable camera

sudo raspi-config

  • expand filesystem
  • enable camera

Reboot.

On the Pi

Here we set up gstreamer to send the output of the Raspi camera to Janus, a webRTC gateway, which can be on a local or remote server.

Update the Pi

sudo apt-get update -y && sudo apt-get upgrade -y

Install gstreamer

sudo apt-get install libgstreamer0.10-0 libgstreamer0.10-dev gstreamer0.10-tools gstreamer0.10-plugins-base libgstreamer-plugins-base0.10-dev gstreamer0.10-plugins-good gstreamer0.10-plugins-ugly gstreamer0.10-plugins-bad libgstreamer-plugins-base1.0-dev

Install Janus on the pi

For a self-contained, easily testable system we also need Janus and nginx on the Pi. Later we’ll install these two on the server too.

Install prerequisites:

sudo aptitude install libmicrohttpd-dev libjansson-dev libnice-dev libssl-dev libsrtp-dev libsofia-sip-ua-dev libglib2.0-dev libopus-dev libogg-dev libini-config-dev libcollection-dev pkg-config gengetopt libtool automake dh-autoreconf

Install Janus:

git clone https://github.com/meetecho/janus-gateway.git
cd janus-gateway
sh autogen.sh
./configure --disable-websockets --disable-data-channels --disable-rabbitmq --disable-docs --prefix=/opt/janus
make
sudo make install
sudo make configs

Configure Janus

sudo pico /opt/janus/etc/janus/janus.plugin.streaming.cfg

[gst-rpwc]
type = rtp
id = 1
description = RPWC H264 test streaming
audio = yes
audioport = 8005
audiopt = 10
audiortpmap = opus/48000/2
video = yes
videoport = 8004
videopt = 96
videortpmap = H264/90000
videofmtp = profile-level-id=42e028\;packetization-mode=1

Install nginx

sudo aptitude install nginx

Install a modified HTML page


cd /usr/share/nginx/www

sudo cp -r /home/pi/janus-gateway/html/* .

sudo curl -O https://gist.githubusercontent.com/libbymiller/70ad942d070853167659/raw/acc38f4ccefb2c333a4cca460ec52a3151cbeebd/janus-gateway-streamtest.html

sudo service nginx start

Test

in one terminal window:

raspivid --verbose --nopreview -hf -vf --width 640 --height 480 --framerate 15 --bitrate 1000000 --profile baseline --timeout 0 -o - | gst-launch-0.10 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! udpsink host=127.0.0.1 port=8004 alsasrc device=plughw:Set ! audioconvert ! audioresample ! opusenc ! rtpopuspay ! udpsink host=127.0.0.1 port=8005

in another:

/opt/janus/bin/janus -F /opt/janus/etc/janus

Go to http://pi-ip/janus-gateway-streamtest.html in Firefox (Chrome doesn’t support h264)

You should get audio and video streaming from your Pi.

On a server

Next we want to stream that to a remote server. The simplest way of doing this is to tell gstreamer to send the streams to the IP of the remote server. In theory we ought to be able to get WebRTC to handle this via Janus, but I’ve not been able to figure out how, nor whether it’s worth it – for our usecase you’re always going to want to stream via a server, we think.

Deploy a server

I used a Linode – Linode 2048, 48GB DISK 2 CPU Cores 3TB XFER .03/hr to $20/mo with 64 bit Ubuntu 14 LTS.

Install Janus and Nginx on the server

sudo apt-get update -y && sudo apt-get upgrade -y

sudo aptitude install libmicrohttpd-dev libjansson-dev libnice-dev libssl-dev libsrtp-dev libsofia-sip-ua-dev libglib2.0-dev libopus-dev libogg-dev libini-config-dev libcollection-dev pkg-config gengetopt libtool automake dh-autoreconf

you may need to do

sudo apt-get install gupnp-igd-1.0

Install Janus:

sudo apt-get install git

git clone https://github.com/meetecho/janus-gateway.git
cd janus-gateway
sh autogen.sh
./configure --disable-websockets --disable-data-channels --disable-rabbitmq --disable-docs --prefix=/opt/janus
make
sudo make install
sudo make configs

Configure Janus

sudo pico /opt/janus/etc/janus/janus.plugin.streaming.cfg

[gst-rpwc]
type = rtp
id = 1
description = RPWC H264 test streaming
audio = yes
audioport = 8005
audiopt = 10
audiortpmap = opus/48000/2
video = yes
videoport = 8004
videopt = 96
videortpmap = H264/90000
videofmtp = profile-level-id=42e028\;packetization-mode=1

Install nginx

sudo aptitude install nginx

Install a modified HTML page

cd /usr/share/nginx/html/

sudo cp -r /opt/janus/share/janus/demos/* .

sudo curl -O https://gist.githubusercontent.com/libbymiller/70ad942d070853167659/raw/acc38f4ccefb2c333a4cca460ec52a3151cbeebd/janus-gateway-streamtest.html

sudo service nginx start

Test it

On the pi:

raspivid --verbose --nopreview -hf -vf --width 640 --height 480 --framerate 15 --bitrate 1000000 --profile baseline --timeout 0 -o - | gst-launch-0.10 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! udpsink host=ip-of-server port=8004 alsasrc device=plughw:Set ! audioconvert ! audioresample ! opusenc ! rtpopuspay ! udpsink host=ip-of-server port=8005

On the server:

/opt/janus/bin/janus -F /opt/janus/etc/janus

on the server you should see

[gst-rpwc] New video stream! (ssrc=460806300)
[gst-rpwc] New audio stream! (ssrc=3733839967)

go to http://ip-of-server/janus-gateway-streamtest.html in Firefox.

Enabling Wifi on the Pi

Just for reference.

Wpasupplicant is normally installed. If it isn’t, do:

sudo apt-get install -y wpasupplicant

Then edit:

sudo pico /etc/wpa_supplicant.conf

network={
ssid="YourWifiNetworkName"
psk="YourWifiNetworkPassword"
}

A version that works only within 10-30 metres

This version uses the wifi card as an access point, so to view the video / audio you connect to the Pi’s access point and then go to the web page on the Pi. Not sure how useful it is, but it’s quite fun, and easy, as you don’t need a separate server on the internet.

Create access point

This is a script we used for Radiodan, slightly modified to just create an access point.

git clone https://github.com/radiodan/provision.git
cd provision

replace the contents of steps/wpa/install.sh

with

sudo apt-get install -y --force-yes dnsmasq && \
sudo apt-get install -y --force-yes ruby1.9.1-dev hostapd=1:1.0-3+deb7u2 wpasupplicant && \
sudo gem install --no-ri --no-rdoc wpa_cli_web

then

sudo mkdir /var/log/radiodan
sudo LOG_LEVEL=DEBUG ./provision avahi nginx wpa

change name of network

sudo pico /etc/hostapd/hostapd.conf

change ssid to

ssid=hackspacehat

edit /etc/nginx/sites-enabled/wpa_cli_web_redirect just this:

server {
listen 80;
root /var/www/html;
}

edit /opt/radiodan/adhoc/try_adhoc_network

to remove

# Do 6 scans over 1 min
#for i in {1..6}
#do
# echo "Scan $i of 6"
# /sbin/wpa_cli scan
# /bin/sleep 10
#done

and also

#echo "Starting wpa-cli-web"
#/etc/init.d/wpa-cli-web start

remove wpa server from init.d

sudo update-rc.d wpa_cli_web remove
sudo update-rc.d wpa-conf-copier remove

reboot

unplug ethernet if plugged in

connect to hackspacehat to check it works – you should be able to ssh to 10.0.0.200.

(this is overkill, but I haven’t had time to investigate a quicker way)

Janus and gstreamer commands

As in the first example, we just run gstreamer sending the streams to localhost, and Janus on the pi.

So two windows on the pi, one sending the streams:

raspivid --verbose --nopreview -hf -vf --width 640 --height 480 --framerate 15 --bitrate 1000000 --profile baseline --timeout 0 -o - | gst-launch-0.10 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! udpsink host=127.0.0.1 port=8004 alsasrc device=plughw:Set ! audioconvert ! audioresample ! opusenc ! rtpopuspay ! udpsink host=127.0.0.1 port=8005

one running Janus:

/opt/janus/bin/janus -F /opt/janus/etc/janus

then connect to AP “hackspacehat” and
go to http://10.0.0.200/janus-gateway-streamtest.html

You should get audio and video from your Pi, which will work while you are in range of the Pi’s access point.