Posts Tagged dashboard-camera

Prevent Motion From Running Without a Camera Connected

Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi, Software Development on July 19, 2013

Introduction

If you read my post, Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg, you know Motion with FFmpeg on a Raspberry Pi makes an ideal dashboard camera system. However, an issue I still struggled with when using the dash-cam was Motion running without a webcam connected.

When I start my car, the Raspberry Pi boots-up, and subsequently, Motion starts. No interaction with the Pi is required. The dash-cam starts capturing images and making the time-lapse video. However, when I get home and plug my Pi back into my local network, Motion starts up again and starts recording blank images and creating the time-lapse video, even though there is no webcam connected.

To get prevent Motion from starting up without a webcam connected, I’ve added a simple function to the Motion startup script. When the system calls Motion on startup, the new function checks if a webcam is connected. If not, it immediately exits the script, without ever starting Motion. No blank images or empty time-lapse videos are created. This saves a lot of wasted processing on the Pi. It also saves a lot of wasted time moving videos and images off the Pi that end up being blank, because no webcam was connected.

Find Your Webcam

First, attach your webcam to the Raspberry Pi. Run the following command to list the USB devices connected to the Pi:

lsusb

You should see similar output to the example below. Note your webcam’s ID(s). I ran the command twice in this example, to identify both of my webcams.

Identifying Webcams with lsusb Command

There are several ways to detect your webcam, depending on you Linux distro. I found this post particularly helpful, The Webcam HOWTO.

Modify Motion

Next, open the Motion startup script, using the following command:

sudo nano /etc/init.d/motion

Add the following ‘check_for_webcam ()’ function to the top of the script, adjacent to the existing ‘check_daemon_enabled()’ function:

# Check if specific webcam(s) are connected to Pi
check_for_webcam () {
    if lsusb | grep -s -q -e 0000:ABCD
    then
        echo "Webcam found. Continuing..."
        return 0
    else
        echo "No webcam found? Shutting down Motion!"
        return 1
    fi
}

You will need to modify the function, changing the string ‘0000:ABCD’, to match your webcam’s ID. If you change your webcam model, remember to update the ID you entered in this function.

Next add the following statement to the beginning of the ‘start’ function. This code calls the new function when Motion’s ‘start’ command is executed. If no webcam is found, the Motion script exits without starting.

if ! check_for_webcam; then
    exit 1
fi

In my example below, I have two possible webcams that might be connected, so I search (grep) for either ID.

Modifying Motion Startup Script

Testing the Script Change

Save and close the Motion script. To test the script is working, run the following command to stop Motion:

sudo /etc/init.d/motion stop

Unplug your webcam from the Raspberry Pi. Then, run the following command to start Motion:

sudo /etc/init.d/motion start

You should see the following output:

No webcam found? Shutting down Motion!

Now, plug your webcam back in and run the ‘start’ command, again. You should now see the following output:

Webcam found. Continuing...

Starting Motion With and Without Webcam

Conclusion

Now, when you start the Raspberry Pi and don’t have a web-cam connected, Motion will no longer automatically start. Just remember, if you don’t have a way to interact directly with your Pi, you will need to restart the Pi to get Motion running again after connecting a webcam.

Dash-Cam, dashboard camera video, dashboard-camera, FFmpeg, Motion, Raspberry Pi, RaspPi, RPi, webcam

Travel-Size Wireless Router for Your Raspberry Pi

Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi, Software Development on July 15, 2013

Use a low-cost nano-size wireless router to connect to your Raspberry Pi while traveling. Set up your own private wireless network in your vehicle, hotel, or coffee shop.

Introduction

Recently, I purchased a USB-powered wireless router for to use with my Raspberry Pi when travelling. In an earlier post, Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg, I discussed the use of the Raspberry Pi, combined with a webcam, Motion, and FFmpeg, to create a low-cost dashboard video camera. Like many, I find one the big challenges with the Raspberry Pi, is how to connect and interact with it. Being in my car, and usually out of range of my home’s wireless network, except maybe in the garage, this becomes even more of an issue. That’s where adding an inexpensive travel-size router to my vehicle comes in handy.

I chose the TP-LINK TL-WR702N Wireless N150 Travel Router, sold by Amazon. The TP-LINK router, described as ‘nano size’, measures only 2.2 inches square by 0.7 inches wide. It has several modes of operation, including as a router, access point, client, bridge, or repeater. It operates at wireless speeds up to 150Mpbs and is compatible with IEEE 802.11b/g/n networks. It supports several common network security protocols, including WEP, WPA/WPA2, WPA-PSK/WPA2-PSK encryption. For $22 USD, what more could you ask for!

My goal with the router was to do the following:

Have the Raspberry Pi auto-connect to the new TP-LINK router’s wireless network when in range, just like my home network.
Since I might still be in range of my home network, have the Raspberry Pi try to connect to the TP-LINK first, before falling back to my home network.
Ensure the network was relatively secure, since I would be exposed to many more potential threats when traveling.

My vehicle has two power outlets. I plug my Raspberry Pi into one outlet and the router into the other. You could daisy chain the router off the Pi. However, my Pi’s ports are in use my the USB wireless adapter and the USB webcam. Using the TP-LINK router, I can easily connect to the Raspberry Pi with my mobile phone or tablet, using an SSH client.

Using Fing to Locate the Pi on the TP-LINK Wireless Network

When I arrive at my destination, I log into the Pi and do a proper shutdown. This activates my shutdown script (see my last post), which moves the newly created Motion/FFmpeg time-lapse dash-cam videos to a secure folder on my Pi, before powering down.

Using SSH Terminal for iOS to Shutdown the Pi

Of course there are many other uses for the router. For example, I can remove the Pi and router from my car and plug it back in at the hotel while traveling, or power the router from my laptop while at work or the coffee shop. I now have my own private wireless network wherever I am to use the Raspberry Pi, or work with other users. Remember the TP-LINK can act as a router, access point, client, bridge, or a repeater.

The Raspberry Pi and Router both fit in a Small Container for Travel

Network Security

Before configuring your Raspberry Pi, the first thing you should do is change all the default security related settings for the router. Start with the default SSID and the PSK password. Both these default values are printed right on the router. That’s motivation enough to change!

Additionally, change the default IP address of the router and the username and password for the browser-based Administration Console.

Lastly, pick the most secure protocol possible. I chose ‘WPA-PSK/WPA2-PSK’. All these changes are done through the TP-LINK’s browser-based Administration Console.

Configuring Multiple Wireless Networks

In an earlier post, Installing a Miniature WiFi Module on the Raspberry Pi (w/ Roaming Enabled), I detailed the installation and configuration of a Miniature WiFi Module, from Adafruit Industries, on a Pi running Soft-float Debian “wheezy”. I normally connect my Pi to my home wireless network. I wanted to continue to do this in the house, but connect the new router when traveling.

Based on the earlier post, I was already using Jouni Malinen’s wpa_supplicant, the WPA Supplicant for Linux, BSD, Mac OS X, and Windows with support for WPA and WPA2. This made network configuration relatively simple. If you use wpa_supplicant, your ‘/etc/network/interfaces’ file should look like the following. If you’re not familiar with configuring the interfaces file for wpa_supplicant, this post on NoWiresSecurity.com is a good starting point.

Note that in this example, I am using DHCP for all wireless network connections. If you chose to use static IP addresses for any of the networks, you will have to change the interfaces file accordingly. Once you add multiple networks, configuring static IP addresses for each network, becomes more complex. That is my next project…

First, I generated a new pre-shared key (PSK) for the router’s SSID configuration using the following command. Substitute your own SSID (‘your_ssid’) and passphrase (‘your_passphrase’).

wpa_passphrase your_ssid your_passphrase

Based your SSID and passphrase, this command will generate a pre-shared key (PSK), similar to the following. Save or copy the PSK to the clipboard. We will need the PSK in the next step.

Then, I modified my wpa_supplicant configuration file with the following command:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

I added the second network configuration, similar to the existing configuration for my home wireless network, using the newly generated PSK. Below is an example of what mine looks like (of course, not the actual PSKs).

Depending on your Raspberry Pi and router configurations, your wpa_supplicant configuration will look slightly different. You may wish to add more settings. Don’t consider my example the absolute right way for your networks.

Wireless Network Priority

Note the priority of the TP-LINK router is set to 2, while my home NETGEAR router is set to 1. This ensures wpa_supplicant will attempt to connect to the TP-LINK network first, before attempting the home network. The higher number gets priority. The best resource I’ve found, which explains all the configuration options is detail, is here. In this example wpa_supplicant configuration file, priority is explained this way, ‘by default, all networks will get same priority group (0). If some of the networks are more desirable, this field can be used to change the order in which wpa_supplicant goes through the networks when selecting a BSS. The priority groups will be iterated in decreasing priority (i.e., the larger the priority value, the sooner the network is matched against the scan results). Within each priority group, networks will be selected based on security policy, signal strength, etc.’

Conclusion

If you want an easy, inexpensive, secure way to connect to your Raspberry Pi, in the vehicle or other location, a travel-size wireless router is a great solution. Best of all, configuring it for your Raspberry Pi is simple if you use wpa_supplicant.

Dash-Cam, dashboard-camera, Debian, FFmpeg, Linux, Motion, Nano Router, Raspberry Pi, RaspPi, RPi, Travel Router, WiFi, Wireless, wpa_supplicant

6 Comments

Using a Startup Script to Save Motion/FFmpeg Videos and Images on The Raspberry Pi

Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi, Software Development on July 9, 2013

Use a start-up script to overcome limitations of Motion/FFmpeg and save multiple Raspberry Pi dashboard camera timelapse videos and images, automatically.

Introduction

In my last post, Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg, I demonstrated how the Raspberry Pi can be used as a low-cost dashboard video camera. One of the challenges I faced in that post was how to save the timelapse videos and individual images (frames) created by Motion and FFmpeg when the Raspberry Pi is turned on and off. Each time the car starts, the Raspberry Pi boots up, and Motion begins to run, the previous images and video, stored in the default ‘/tmp/motion/’ directory are removed and new images and video, created.

Take the average daily commute, we drive to and from work. Maybe we stop for a morning coffee, or stop at the store on the way home to pick up dinner. Maybe we use our car go out for lunch. Our car starts, stops, starts, stops, starts, and stops. Our daily commute actually encompasses a series small trips, and therefore multiple dash-cam timelapse videos. If you are only interested in keeping the latest timelapse video in case of an accident, then this may not be a problem. When the accident occurs, simply pull the SDHC card from the Raspberry Pi and copy the video and images off to your laptop.

However, if you are interested in capturing and preserving series of dash-cam videos, such as in the daily commute example above, then the default behavior of Motion is insufficient. To preserve each video segment or series of images, we need a way to preserve the content created by Motion and FFmpeg, before they are overwritten. In this post, I will present a solution to overcome this limitation.

The process involves the following steps:

Change the default location where Motion stores timelapse videos and images to somewhere other than a temporary directory;
Create a startup script that will move the video and images to a safe location when restarting the Pi;
Configure the Pi’s Debian operating system to run this script at startup (and optionally shutdown), before Motion starts;

Sounds pretty simple. However, understanding how startup scripts work with Debian’s Init program, making sure the new move script run before Motion starts, and knowing how to move a huge number of files, all required forethought.

Change Motion’s Default Location for Video and Images

To start, change the default location where Motion stores timelapse video and images, from ‘/tmp/motion/’ to a location outside the ‘/tmp’ directory. I chose to create a directory called ‘/motiontmp’. Make sure you set the permissions on the new ‘/motiontmp’ directory, so Motion can write to it:

sudo chmod -R 777 /motiontmp

To have Motion use this location, we need to modify the Motion configuration file:

sudo nano /etc/motion/motion.conf

Change the following setting (in bold below). Note when Motion starts for the first time, it will create the ‘motion’ sub folder inside ‘motiontmp’. You do not have to create it yourself.

# Target base directory for pictures and films
# Recommended to use absolute path. (Default: current working directory)
target_dir /motiontmp/motion

Create the Startup Script to Move Video and Images

Next, create the new shell script that will run at startup to move Motion’s video and images. The script creates a timestamped folder in new ‘motiontmp’ directory for each series of images and video. The script then copies all files from the ‘motion’ directory to the new timestamped directory. Before copying, the script deletes any zero-byte jpegs, which are images that did not fully process prior to the Raspberry Pi being shut off when the car stopped. To create the new script, run the following command.

sudo nano /etc/init.d/motionStartup.sh

Copy the following contents into the script and save it.

### BEGIN INIT INFO
# Provides:          motionStartup
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Move motion files at startup.
# Description:       Move motion files at startup.
# X-Start-Before:    motion
### END INIT INFO

#! /bin/sh
# /etc/init.d/motionStartup
#

# Some things that run always
#touch /var/lock/motionStartup
logger -s "Script motionStartup called"

# Carry out specific functions when asked to by the system
case "$1" in
  start)
    logger -s "Script motionStartup started"
    TIMESTAMP=$(date +%Y%m%d%H%M%S | sed 's/ //g') # No spaces
    logger -s "Script motionStartup $TIMESTAMP"
    sudo mkdir /motiontmp/$TIMESTAMP || logger -s "Error mkdir start"
    find /motiontmp/motion/. -type f -size 0 -print0 -delete
    find /motiontmp/motion/. -maxdepth 1 -type f | \
        xargs -I '{}' sudo mv {} /motiontmp/$TIMESTAMP
    ;;
  stop)
    logger -s "Script motionStartup stopped"
    ;;
  *)
    echo "Usage: /etc/init.d/motionStartup {start|stop}"
    exit 1
    ;;
esac

exit 0

Note the ‘X-Start-Before’ setting at the top of the script (in bold). An explanation of this setting is found on the Debian Wiki website. According to the site, ”There is no such standard-defined header, but there is a proposed extension implemented in the insserv package (since version 1.09.0-8). Use the X-Start-Before and X-Stop-After headers proposed by SuSe.” To make sure you have a current version of ‘insserv‘, you can run the following command:

dpkg -l insserv

Also, note how the files are moved by the script:

find /motiontmp/motion/. -maxdepth 1 -type f | \
        xargs -I '{}' sudo mv {} /motiontmp/$TIMESTAMP

It’s not as simple as using ‘mv *.*’ when you have a few thousand files. This will likely throw a ‘Argument list too long’ exception. According to one stackoverflow, the exception is because bash actually expands the asterisk to every matching file, producing a very long command line. Using the ‘find’ combined with ‘xargs’ gets around these problem. The ‘xargs’ command splits up the list and issues several commands if necessary. This issue applies to several commands, including rm, cp, and mv.

Lastly, note the use of the ‘logger‘ commands throughout the script. These are optional and may be removed. I like to log the script’s progress for troubleshooting purposes. Using the above ‘logger’ commands, I can easily pinpoint issues by looking at the log with grep, such as:

tail -500 /var/log/messages | grep 'motionStartup' | grep 'logger:'

You can test the script by running the following command:

/etc/init.d/./motionStartup.sh start

You should see a series of three messages output to the screen by the script, confirming the script is working. Note the new timestamped folder created by the script, below.

Below, is an example of the how the directory structure should look after a few videos are created by Motion, and the Raspberry Pi cycled off and on. You need to complete the rest of the steps in this post for this to work automatically.

Shutdown Script?

I know, the name of the post clearly says ‘Startup Script’. Well, a little tip, if you copy the code from the ‘start’ method and paste it in the ‘stop’ method, this now also works at shutdown. If you do a proper shutdown (like ‘sudo reboot’), the Raspberry Pi’s OS will call the script’s ‘stop’ method. The ‘start’ method is more useful to use for us in the car, where we may not be able to do a proper shutdown; we just turn the car off and kill power to the Pi. However, if you are shutting down from mobile device via ssh, or using a micro keyboard and LCD monitor, the script will do it’s work on the way down.

Configure Debian OS to Run the New Startup Script

To have our new script run on startup, install it by running the following command:

sudo update-rc.d motionStartup.sh defaults

A full explanation of this command is to complex for this brief post. A good overview of creating startup scripts and installing them in Debian is found on the Debian Administration website. This is the source I used to start to understand runlevels. There are also a few links at the end of the post. To tell which runlevel (state) you running at, use the following command:

runlevel

To make sure the startup script was installed properly, run the following command. This will display the contents of each ‘rc*.d’ folder. Each folder corresponds to a runlevel – 0, 1, 2, etc. Each folder contains symbolic links to the actual scripts. The links are named by order of executed (S01…, S02…, S03…):

ls /etc/rc*.d

Look for the new script listed under the appropriate runlevel(s). The new script should be listed before ‘motion’, as shown below.

If for any reason you need to uninstall the new script (not delete/remove), run the following command. This not a common task, but necessary to change the order of execution of the scripts or rename a script.

sudo update-rc.d -f motionStartup.sh remove

Copy and Remove Files from the Raspberry Pi

Once the startup script is working and we are capturing images and timelapse video, the next thing we will probably want to do is copy files off the Raspberry Pi. To do this over your WiFi network, use a ‘scp’ command from a remote machine. The below script copies all directories, stating with ‘2013’, and their contents to remote machine, preserving the directory structure.

scp -rp user@ip_address_of_pi:/motiontmp/2013* ~/local_directory/

Maybe you just want all the timelapse videos Motion/FFmpeg creates; you don’t care about the images. The following command copies just the MPEG videos from all ‘2013’ folders to a single directory on the your remote machine. The directory structure is ignored during the copy. This is the quickest way to just store all the videos.

scp -rp user@ip_address_of_pi:/motiontmp/2013*/*.mpg ~/local_directory/

If you are going to save all the MPEG timelapse videos in one location, I recommend changing the naming convention of the videos in the motion.conf file. I have added the hour, minute, and seconds to mine. This will ensure the names don’t conflict when moved to a common directory:

# File path for timelapse mpegs relative to target_dir
# Default: %Y%m%d-timelapse
# Default value is near equivalent to legacy oldlayout option
# For Motion 3.0 compatible mode choose: %Y/%m/%d-timelapse
# File extension .mpg is automatically added so do not include this
timelapse_filename %Y%m%d%H%M%S-timelapse

To remove all the videos and images once they have been moved off the Pi and are no longer needed, you can run a rm command. Using the ‘-rf’ options make sure the directories and their contents are removed.

sudo rm -rf /motiontmp/2013*

Conclusion

The only issue I have yet to overcome is maintaining the current time on the Raspberry Pi. The Pi lacks a Real Time Clock (RTC). Therefore, turning the Pi on and off in the car causes it to loose the current time. Since the Pi is not always on a WiFi network, it can’t sync to the current time when restarted. The only side-effects I’ve seen so far caused by this, the videos occasionally contain more than one driving event and the time displayed in the videos is not always correct. Otherwise, the process works pretty well.

Resources

The following are some useful resources on this topic:

Debian Reference: Chapter 3. The system initialization

How-To: Managing services with update-rc.d

Files and scripts that execute on boot

Making scripts run at boot time with Debian

Finding all files and move to new directory from shell prompt

Shell scripting: Write message to a syslog / log file

“Argument list too long”: Beyond Arguments and Limitations

Linux / Unix Command: date (used for TIMESTAMP)

Time / Date Commands

To have our new script run on startup, install it by running the following command:

dashboard-camera, Debian, FFmpeg, Linux, Motion, Rasp Pi, Raspberry Pi, runlevel, start-up script, startup script, video

3 Comments

Raspberry Pi-Powered Dashboard Video Camera Using Motion and FFmpeg

Posted by Gary A. Stafford in Bash Scripting, Raspberry Pi, Software Development on June 30, 2013

Demonstrate the use of the Raspberry Pi and a basic webcam, along with Motion and FFmpeg, to build low-cost dashboard video camera for your daily commute.

Dashboard Video Cameras

Most of us remember the proliferation of dashboard camera videos of the February 2013 meteor racing across the skies of Russia. This rare astronomical event was captured on many Russian motorist’s dashboard cameras. Due to the dangerous driving conditions in Russia, many drivers rely on dashboard cameras for insurance and legal purposes. In the United States, we are more use to seeing dashboard cameras used by law-enforcement. Who hasn’t seen those thrilling police videos of car crashes, drunk drivers, and traffic stops gone wrong.

Although driving in the United States is not as dangerous as in Russia, there is reason we can’t also use dashboard cameras. In case you are involved in an accident, you will have a video record of the event for your insurance company. If you witness an accident or other dangerous situation, your video may help law enforcement and other emergency responders. Maybe you just want to record a video diary of your next road trip.

A wide variety of dashboard video cameras, available for civilian vehicles, can be seen on Amazon’s website. They range in price and quality from less that $50 USD to well over $300 USD or more, depending on their features. In a popular earlier post, Remote Motion-Activated Web-Based Surveillance with Raspberry Pi, I demonstrated the use of the Raspberry Pi and a webcam, along with Motion and FFmpeg, to provide low-cost web-based, remote surveillance. There are many other uses for this combination of hardware and software, including as a dashboard video camera.

Methods for Creating Dashboard Camera Videos

I’ve found two methods for capturing dashboard camera videos. The first and easiest method involves configuring Motion to use FFmpeg to create a video. FFmpeg creates a video from individual images (frames) taken at regular intervals while driving. The upside of the FFmpeg option, it gives you a quick ready-made video. The downside of FFmpeg option, your inability to fully control the high-level of video compression and high frame-rate (fps). This makes it hard to discern fine details when viewing the video.

Alternately, you can capture individual JPEG images and combine them using FFmpeg from the command line or using third-party movie-editing tools. The advantage of combining the images yourself, you have more control over the quality and frame-rate of the video. Altering the frame-rate, alters your perception of the speed of the vehicle recording the video. The only disadvantage of combining the images yourself, you have the extra steps involved to process the images into a video.

At one frame every two seconds (.5 fps), a 30 minute commute to work will generate 30 frames/minute x 30 minutes, or 900 jpeg images. At 640 x 480 pixels, depending on your jpeg compression ratio, that’s a lot of data to move around and crunch into a video. If you just want a basic record of your travels, use FFmpeg. If you want a higher-quality record of trip, maybe for a video-diary, combining the frames yourself is a better way to go.

Configuring Motion for a Dashboard Camera

The installation and setup of FFmpeg and Motion are covered in my earlier post so I won’t repeat that here. Below are several Motion settings I recommend starting with for use with a dashboard video camera. To configure Motion, open it’s configuration file, by entering the following command on your Raspberry Pi:

sudo nano /etc/motion/motion.conf

To use FFmpeg, the first method, find the ‘FFMPEG related options’ section of the configuration and locate ‘Use ffmpeg to encode a timelapse movie’. Enter a number for the ‘ffmpeg_timelapse’ setting. This is the rate at which images are captured and combined into a video. I suggest starting with 2 seconds. With a dashboard camera, you are trying to record important events as you drive. In as little as 2-3 seconds at 55 mph, you can miss a lot of action. Moving the setting down to 1 second will give more detail, but you will chew up a lot of disk space, if that is an issue for you. I would experiment with different values:

# Use ffmpeg to encode a timelapse movie
# Default value 0 = off - else save frame every Nth second
ffmpeg_timelapse 2

To use the ‘do-it-yourself’ FFmpeg method, locate the ‘Snapshots’ section. Find ‘Make automated snapshot every N seconds (default: 0 = disabled)’. Change the ‘snapshot_interval’ setting, using the same logic as the ‘ffmpeg_timelapse’ setting, above:

# Make automated snapshot every N seconds (default: 0 = disabled)
snapshot_interval 2

Irregardless of which method you choose (or use them both), you will want to tweak some more settings. In the ‘Text Display’ section, locate ‘Set to ‘preview’ will only draw a box in preview_shot pictures.’ Change the ‘locate’ setting to ‘off’. As shown in the video frame below, since you are moving in your vehicle most of the time, there is no sense turning on this option. Motion cannot differentiate between the highway zipping by the camera and the approaching vehicles. Everything is in motion to the camera, the box just gets in the way:

# Set to 'preview' will only draw a box in preview_shot pictures.
locate off

Optionally, I recommend turning on the time-stamp option. This is found right below the ‘locate’ setting. Especially in the event of an accident, you want an accurate time-stamp on the video or still images (make sure you Raspberry Pi’s time is correct):

# Draws the timestamp using same options as C function strftime(3)
# Default: %Y-%m-%d\n%T = date in ISO format and time in 24 hour clock
# Text is placed in lower right corner
text_right %Y-%m-%d\n%T-%q

Starting with the largest, best quality images will ensure the video quality is optimal. Start with a large size capture and reduce it only if you are having trouble capturing the video quickly enough. These settings are found in the ‘Capture device options’ section:

# Image width (pixels). Valid range: Camera dependent, default: 352
width 640

# Image height (pixels). Valid range: Camera dependent, default: 288
height 480

Similarly, I suggest starting with a low amount of jpeg compression to maximize quality and only lower if necessary. This setting is found in the ‘Image File Output’ section:

# The quality (in percent) to be used by the jpeg compression (default: 75)
quality 90

Once you have completed the configuration of Motion, restart Motion for the changes to take effect:

sudo /etc/init.d/motion restart

Since you will be powering on your Raspberry Pi in your vehicle, and may have no way to reach Motion from a command line, you will want Motion to start capturing video and images for you automatically at startup. To enable Motion (the motion daemon) on start-up, edit the /etc/default/motion file.

sudo nano /etc/default/motion

Change the ‘start_motion_daemon‘ setting to ‘yes’. If you decide to stop using the Raspberry Pi for capturing video, remember to disable this option. Motion will keep generating video and images, even without a camera connected, if the daemon process is running.

Capturing Dashboard Video

Although taking dashboard camera videos with your Raspberry Pi sounds easy, it presents several challenges. How will you mount your camera? How will you adjust your camera’s view? How will you power your Raspberry Pi in the vehicle? How will you power-down your Raspberry Pi from the vehicle? How will you make sure Motion is running? How will you get the video and images off the Raspberry Pi? Do you have one a mini keyboard and LCD monitor to use in your vehicle? Or, is your Raspberry Pi on your wireless network? If so, do you know how to bring up the camera’s view and Motion’s admin site on your smartphone’s web-browser?

My start-up process is as follows:

Start my car.
Plug the webcam and the power cable into the Raspberry Pi.
Let the Raspberry Pi boot up fully and allow Motion to start. This takes less than one minute.
Open the http address Motion serves up using my mobile browser.
(Since my Raspberry Pi has a wireless USB adapter installed and I’m still able to connect from my garage).
Adjust the camera using the mobile browser view from the camera.
Optionally, use Motion’s ‘HTTP Based Control’ feature to adjust any Motion configurations, on-the-fly (great option).

Logitech Webcam C210 Webcam Mounted on Car Sun Visor

Raspberry Pi in Vehicle with iPhone Preview of Dashboard Camera

Adjusting Dashboard Camera using iPhone Preview over LAN Connection to Raspberry Pi

Adjusting Camera using iPhone WiFi Connection to Raspberry Pi

Using Motion’s HTTP Based Control on iPhone Mobile Web Browser

Once I reach my destination, I copy the video and/or still image frames off the Raspberry Pi:

Let the car run for at least 1-2 minutes after you stop. The Raspberry Pi is still processing the images and video.
Copy the files off the Raspberry Pi over the local network, right from car (if in range of my LAN).
Alternately, shut down the Raspberry Pi by using a SSH mobile app on your smartphone, or just shut the car off (this not the safest method!).
Place the Pi’s SDHC card into my laptop and copy the video and/or still image frames.

Shutting Down Raspberry Pi Using SSH Terminal iPhone App

Here are some tips I’ve found to make creating dashboard camera video’s easier and better quality:

Leave your camera in your vehicle once you mount and position it.
Make sure your camera is secure so the vehicle’s vibrations while driving don’t create bouncy-images or change the position of the camera field of view.
Clean your vehicle’s front window, inside and out. Bugs or other dirt are picked up by the camera and may affect the webcam’s focus.
Likewise, film on the window from smoking or dirt will soften the details of the video and create harsh glare when driving on sunny days.
Similarly, make sure your camera’s lens is clean.
Keep your dashboard clear of objects such as paper, as it reflects on the window and will obscure the dashboard camera’s video.
Constantly stopping your Raspberry Pi by shutting the vehicle off can potential damage the Raspberry Pi and/or corrupt the operating system.
Make sure to keep your Raspberry Pi out of sight of potential thieves and the direct sun when you are not driving.
Backup your Raspberry Pi’s SDHC card before using for dashboard camera, see Duplicating Your Raspberry Pi’s SDHC Card.

Creating Video from Individual Dashboard Camera Images

FFmpeg

If you choose the second method for capturing dashboard camera videos, the easiest way to combine the individual dashboard camera images is by calling FFmpeg from the command line. To create the example #3 video, shown below, I ran two commands from a Linux Terminal prompt. The first command is a bash command to rename all the images to four-digit incremented numbers (‘0001.jpg’, ‘0002.jpg’, ‘0003.jpg’, etc.). This makes it easier to execute the second command. I found this script on stackoverflow. It requires Gawk (‘sudo apt-get install gawk’). If you are unsure about running this command, make a copy of the original images in case something goes wrong.

The second command is a basic FFmpeg command to combine the images into a 20 fps MPEG-4 video file. More information on running FFmpeg can be found on their website. There is a huge number of options available with FFmpeg from the command line. Running this command, FFmpeg processed 4,666 frames at 640 x 480 pixels in 233.30 seconds, outputting a 147.5 Mb MPEG-4 video file.

find -name '*.jpg' | sort | gawk '{ printf "mv %s %04d.jpg\n", $0, NR }' | bash 
ffmpeg -r 20 -qscale 2  -i %04d.jpg output.mp4

FFmpeg Command Line Video Creation Output

Example #3 – FFmpeg Video from Command Line

If you want to compress the video, you can chain a second FFmpeg command to the first one, similar to the one below. In my tests, this reduced the video size to 20-25% of the original uncompressed version.

ffmpeg -r 20 -qscale 2 -i %04d.jpg output.mp4 && ffmpeg -i output.mp4 -vcodec mpeg2video output_compressed.mp4

If your images are to dark (early morning or overcast) or have a color-cast (poor webcam or tinted-windows), you can use programs like ImageMagick to adjust all the images as a single batch. In example #5 below, I pre-processed all the images prior to making the video. With one ImageMagick command, I adjusting their levels to make them lighter and less flat.

mogrify -level 12%,98%,1.79 *.jpg

Example #5 – FFmpeg Uncompressed Video from Command Line

Windows MovieMaker

Using Windows MovieMaker was not my first choice, but I’ve had a tough time finding an equivalent Linux gui-based application. If you are going to create your own video from the still images, you need to be able to import and adjust thousands of images quickly and easily. I can import, create, and export a typical video of a 30 minute trip in 10 minutes with MovieMaker. With MovieMaker, you can also add titles, special effects, and so forth.

Single Images Combined in Windows MovieMaker

Sample Videos

Below are a few dashboard video examples using a variety of methods. In the first two examples, I captured still images and created the FFmpeg video at the same time. You can compare quality of Method #1 to #2.

Example #2a – Motion/FFmpeg Video