In this project, you will use a Raspberry Pi and a Pi NoIR camera to allow you to observe nesting birds without disturbing them. This advanced worksheet covers how to stream the video you produce to the internet.
Ustream is one of the most popular live video streaming sites on the internet. It's used by NASA to stream video from the International Space Station to all over the world. Websites like Ustream, YouTube Live, and Bambuser are known as content distribution services.
We need to use a service like this because you could potentially have thousands of people watching your bird box simultaneously. If you were to try and host that many viewers from your own internet connection, your router would probably go into meltdown. There would simply not be enough upload bandwidth.
With a content distribution service provider, you send your video content to them and they then host the connection to all the viewers. Therefore, you offload that bandwidth requirement from your own internet connection to them, and you don't have to worry about how many people are concurrently watching the bird box or how much bandwidth is being used.
The only drawback is that there will be a delay on the video. For example, if you poked your finger into the bird box, you would only see it online 20 to 30 seconds later. This delay is known as latency. Despite this, however, the service will make a perfectly viable solution for sharing the bird box with the world.
Firstly, you need to install some software called FFmpeg on the Raspberry Pi which will continually stream the video data from the camera board to the web. Instructions are below.
NOTE: This step is going to take about two hours since you have to compile the program from its source code. The Raspbian FFmpeg package that can be installed using apt-get doesn't have the required h264 video encoder support. You can just set the process going and do something else during this time; you'll also only need to do it once.
The part that takes two hours is the make command at the end of the list below. The ./configure part takes a while too; just be patient. Enter the following commands to download, compile and install FFmpeg:
cd /usr/src
sudo mkdir ffmpeg
sudo chown pi:users ffmpeg
git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg
cd ffmpeg
./configure
make && sudo make installYou can now do something else until you see the command prompt reappear.
If you have not done so already, go to ustream.tv and click Sign Up (you can use another computer or device for this instead of the Pi).
Enter your details to create an account for yourself. During the signup process you'll be asked to create a channel; try to think of an interesting name for it, so that people who find it will remember it easily.
Feel free to customise it, and do give your channel an avatar as well.
The account will be free and will do everything we need it to. However, after 30 days some adverts will show on the side of the page where your live video is: this is part of the Ustream business model. You can buy a pro account which will give you access to many more features, as well as disabling the adverts, but that isn't necessary for this project.
We need to copy two settings from your Ustream account to use on the Raspberry Pi: the RTMP address and the stream key. These two settings are needed by FFmpeg so that the data is streamed to the correct Ustream channel.
To find these two settings follow the steps below:
- Log in
- Select Dashboard from the top right menu
- Select CHANNELS from the left hand menu
- Select your channel
- Select Broadcast Settings
- Select Encoder settings > View
You should then see the screen below. The RTMP URL and Stream Key fields will contain text. Keep this page open for use in the next step.
The intention is to stream the video content from the bird box constantly to the internet. Considering that internet servers can go down, it's a good idea to ensure that the Raspberry Pi will keep trying to send out the video stream if there is a problem.
To do that we can create a small shell script with a while loop; inside that loop is the command to start the stream. If something causes the stream command to go wrong and exit, the shell script will go around the loop and try the command again indefinitely.
Let's create a script on the Raspberry Pi to do this. Enter the following command:
nano ~/ustreamNow copy and paste the code below, but replace <rtmpurl> and <streamkey> with the corresponding values from your own Ustream encoder settings page (see previous step):
#!/bin/bash
RTMP_URL=<rtmpurl>
STREAM_KEY=<streamkey>
while :
do
raspivid -n -vf -hf -t 0 -w 960 -h 540 -fps 25 -b 500000 -o - | ffmpeg -i - -vcodec copy -an -metadata title="Streaming from raspberry pi camera" -f flv $RTMP_URL/$STREAM_KEY
sleep 2
donePress Ctrl + O then Enter to save and Ctrl + X to quit.
We're almost there. Enter the following command to make the shell script executable:
chmod +x ~/ustreamNow whenever you want to go live just use the following command:
~/ustreamYou can view the live stream on a PC or laptop by going to the Ustream channel URL in a browser. This can be accessed using the 
icon on the right of your channel name under CHANNELS in the Ustream dashboard. See the green square in the screen shot above.
When you have the video feed on screen, perform a test to see what the latency is like. Poke your finger inside the entrance of the bird box and time how long it takes to appear online. The delay should only be about 20-30 seconds.
The URL in the browser address bar can now be sent to your friends over email, Facebook or Twitter and they should all be able to view what is happening in your bird box.
Press Ctrl + C twice when you want to shut the stream down.
The last thing you should consider is being able to access the Raspberry Pi remotely from another computer without having to have a keyboard, mouse and monitor connected to it. This would be pretty inconvenient if the Pi is located somewhere outside, like up a tree.
You should familiarise yourself with Secure Shell (SSH). This is a technique that allows you to have the Raspberry Pi command prompt inside a window on another PC or Mac. As long as the other computer has network access to the Raspberry Pi, you can have full remote control.
The instructions here cover how to do this from Windows, OS X or Linux.
After you're comfortable with that you'll need a way to run ~/ustream over SSH and then disconnect from the Pi, leaving it running. If you were to run ~/ustream in an SSH window and then close that window, you wouldn't be able to get back to it to see if there was a problem. Ideally, you don't really want to keep an SSH window open at all times on another PC or Mac, so here is a simple way to solve this problem.
Screen is a utility that allows you to have multiple terminal sessions with only one SSH connection to the Pi. It's incredibly handy and once you've used it, you'll use it all the time.
Screen works like virtual command prompt, and you can have as many screens open as you want. When you start a screen you're automatically connected to it and can see what it shows. You can start a program and then disconnect from the screen but leave it running in the background. Later on you can come back and reconnect to the screen and see what has happened while you were away. Let's try it now.
Firstly, you'll need to install it as it doesn't come installed by default. You'll only need to do this once:
sudo apt-get install screenThen, to start a new session enter the following command:
screen bashThis will now give you a blank session showing the command prompt. Enter the command below (this is the terminal equivalent of Task Manager in Windows):
topWe'll use this as our program to leave running in the background. Now press Ctrl + A + D to disconnect from the screen. You should be back at the previous command prompt. Now close the SSH window completely, wait a few seconds and re-connect.
To get back into and resume the screen session enter the following command:
screen -rYou should now be looking at top once again, you can see it's still running and has been the entire time you were disconnected. Press Ctrl + C to close top, and then you can type exit to close down the screen session.
We can now make the Raspberry Pi start a screen for the ~/ustream script at boot time. That way if the bird box ever loses power, from a power cut for instance, it will reboot and start streaming video to the internet automatically without any human intervention.
Enter the command below:
sudo nano /etc/rc.local
This file is a script which runs every time the Raspberry Pi boots up. At the end of the file you'll see exit 0; copy and paste the command below onto the previous line:
screen -S birdbox -dms birdbox /home/pi/ustreamPress Ctrl + O then Enter to save and Ctrl + X to quit.
Reboot now to test it.
sudo reboot
Reload the Ustream channel URL on another computer, when the Raspberry Pi boots back up, and you should see the video feed. Remember there will be about a 20 to 30 second delay on what you see.
The screen session that we started automatically will be running as the root user so you can reconnect to it using the command below:
sudo screen -r- Wait for some birds to move in
- Tell the world about your bird box
- Post the Ustream channel URL on social media or email it to your friends and family