There are plenty of generally accessible webcams. Instead of just tuning in and watching, I wrote some perl scripts \u00a0to grab pictures at regular intervals and then put them together into time-lapse movies. I’m fond of Madison, Wisconsin, because I grew up there.<\/p>\n
This Perl script generates a one-day movie from the King Hall, Lake Mendota cam:<\/p>\n
#!\/usr\/bin\/perl -w\r\n\r\n# get_webcam_pics Bill Feiereisen, February 22, 2017\r\n# Put this script in a file ending in .pl For example --> get_webcam_pics.pl\r\n# Place it in a new directory. Execute it with .\/get_webcam_pics.pl\r\n# Patience! It runs for a long time depending on how many pictures and the wait interval\r\n\r\n# Gets webcam pictures at regular intervals from public webcams and stores\r\n# them for later processing into a time-lapse movie.\r\n# Downloads from the chosen camera URL with curl.\r\n# Creates a sequential filename for each picture and stores in the current directory.\r\n# After the main loop calls ffmpeg to generate the movie from stored frames.\r\n# You gotta have curl and ffmpeg installed on your system.\r\n# You could do the downloading with wget if you don't have curl.\r\n\r\n# identify script to the terminal.\r\n print \"get_webcam_pics Bill Feiereisen February 22, 2017\\n\";\r\n\r\n# Here's where this particular cam stores its files.\r\n $CAM_URL=\"http:\/\/agwx.soils.wisc.edu\/soils-agwx-assets\/uwex_agwx\/images\/webcam\/fullsize.jpg\";\r\n $CAM_NAME=\"Lake_Mendota\";\r\n\r\n# picture counter limit\r\n# This is one day at five minute intervals.\r\n $ipic_max = 288; #How many pictures? Change to suit.\r\n# sleep time\r\n $sleep_tics = 300; #This is 300 seconds, five minute interval. Change to suit.\r\n\r\n# main picture gathering loop\r\n for ($ipic = 0; $ipic < $ipic_max; $ipic+=1) { # main loop\r\n $picture_name = \"$CAM_NAME$ipic.jpg\"; # create filename with sequential numbered files\r\n print \"$picture_name\\n\"; # print something to the terminal so you know what's happening.\r\n system(\"curl -o $picture_name $CAM_URL;\"); # get the picture and store it\r\n sleep $sleep_tics; #sleep for a while until the next picture is available.\r\n } #end picture gathering loop\r\n\r\n# make movie with ffmpeg\r\n# for this call use 15fps, start with file number 0, code at 1280x800\r\n system(\"ffmpeg -r 15 -start_number 0 -i $CAM_NAME%d.jpg -s 1280x800 -vcodec libx264 $CAM_NAME.mp4;\");\r\n\r\n# end of main program\r\n exit;<\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
There are plenty of generally accessible webcams. Instead of just tuning in and watching, I wrote some perl scripts \u00a0to grab pictures at regular intervals and then put them together into time-lapse movies. I’m fond of Madison, Wisconsin, because I … Continue reading