├── .gitignore
├── pmcam.sh
└── README.md


/.gitignore:
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1 | .DS_Store
2 | images/
3 | 


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/pmcam.sh:
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 1 | #!/usr/bin/env bash
 2 | 
 3 | SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 4 | OUTPUT_DIR="$SCRIPT_DIR/images"
 5 | 
 6 | CAPTURE_INTERVAL="1" # in seconds
 7 | FFMPEG=ffmpeg
 8 | command -v $FFMPEG >/dev/null 2>&1 || { FFMPEG=avconv ; }
 9 | DIFF_RESULT_FILE=$OUTPUT_DIR/diff_results.txt
10 | 
11 | fn_cleanup() {
12 | 	rm -f diff.png $DIFF_RESULT_FILE
13 | }
14 | 
15 | fn_terminate_script() {
16 | 	fn_cleanup
17 | 	echo "SIGINT caught."
18 | 	exit 0
19 | }
20 | trap 'fn_terminate_script' SIGINT
21 | 
22 | mkdir -p $OUTPUT_DIR
23 | PREVIOUS_FILENAME=""
24 | while true ; do
25 | 	FILENAME="$OUTPUT_DIR/$(date +"%Y%m%dT%H%M%S").jpg"
26 | 	echo "-----------------------------------------"
27 | 	echo "Capturing $FILENAME"
28 | 	if [[ "$OSTYPE" == "linux-gnu" ]]; then
29 | 		$FFMPEG -loglevel fatal -f video4linux2 -i /dev/video0 -r 1 -t 0.0001 $FILENAME
30 | 	elif [[ "$OSTYPE" == "darwin"* ]]; then
31 | 		# Mac OSX
32 | 		$FFMPEG -loglevel fatal -f avfoundation -i "default" -r 1 -t 0.0001 $FILENAME
33 | 	fi
34 | 	
35 | 	if [[ "$PREVIOUS_FILENAME" != "" ]]; then
36 | 		# For some reason, `compare` outputs the result to stderr so
37 | 		# it's not possibly to directly get the result. It needs to be
38 | 		# redirected to a temp file first.
39 | 		compare -fuzz 20% -metric ae $PREVIOUS_FILENAME $FILENAME diff.png 2> $DIFF_RESULT_FILE
40 | 		DIFF="$(cat $DIFF_RESULT_FILE)"
41 | 		fn_cleanup
42 | 		if [ "$DIFF" -lt 20 ]; then
43 | 			echo "Same as previous image: delete (Diff = $DIFF)"
44 | 			rm -f $FILENAME
45 | 		else
46 | 			echo "Different image: keep (Diff = $DIFF)"
47 | 			PREVIOUS_FILENAME="$FILENAME"
48 | 		fi
49 | 	else
50 | 		PREVIOUS_FILENAME="$FILENAME"
51 | 	fi
52 | 	
53 | 	sleep $CAPTURE_INTERVAL
54 | done
55 | 


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/README.md:
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 1 | # pmcam - poor man's video capture with motion detection in Bash
 2 | 
 3 | This simple Bash script captures images from a webcam with motion detection support. I wanted to find out what my dog was up to when I am not at home, but could not find any free video capture software on OS X. I put together this quick and dirty solution, which does the job surprisingly well.
 4 | 
 5 | Frames are captured at regular intervals using `ffmpeg`. Then ImageMagick's `compare` tool is used to check if this frame is similar to the previous one. If the frames are different enough, they are kept, otherwise they are deleted. This provide very simple motion detection and avoids filling up the hard drive with duplicate frames.
 6 | 
 7 | ## Installation
 8 | 
 9 | ### OS X
10 | 
11 | 	brew install ffmpeg
12 | 	brew install imagemagick
13 | 	curl -O https://raw.github.com/laurent22/pmcam/master/pmcam.sh
14 | 
15 | ### Linux (Debian)
16 | 
17 | 	sudo apt-get install ffmpeg
18 | 	# or: sudo apt-get install libav-tools
19 | 	sudo apt-get install imagemagick
20 | 	curl -O https://raw.github.com/laurent22/pmcam/master/pmcam.sh
21 | 
22 | ### Windows
23 | 
24 | (Not tested)
25 | 
26 | * Install [Cygwin](https://www.cygwin.com/) or [MinGW](http://www.mingw.org/)
27 | * Install [ffmpeg](http://ffmpeg.zeranoe.com/builds/)
28 | * Install [ImageMagick](http://www.imagemagick.org/script/binary-releases.php)
29 | 
30 | ## Usage
31 | 
32 | 	./pmcam.sh
33 | 
34 | The script will use the default webcam to capture frames. To capture using a different camera, the ffmpeg command `-i` parameter can be changed - see the [ffmpeg documentation](https://trac.ffmpeg.org/wiki/Capture/Webcam) for more information.
35 | 
36 | A frame will then be saved approximately every 1 second to the "images" folder next to the Bash script. Both delay and target folder can be changed in the script.
37 | 
38 | To stop the script, press Ctrl + C.
39 | 
40 | ## TODO
41 | 
42 | * Allow specifying the video capture source and format (curently hardcoded)
43 | * Command line argument to change frame directory.
44 | * Command line argument to change interval between frame captures.
45 | * Command line argument to specify the threshold for a frame to be kept.
46 | 
47 | ## License
48 | 
49 | MIT
50 | 


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