Creating a video from webcam still images with crontab and ffmpeg

I have a webcam that is taking images when there is movement in its view field. It uploads them to a ftp server. I wanted some automated method to generate a video file from the images of the previous day. Finally I came up with the following shell script which is living under /etc/cron.daily:


#!/bin/sh
#
# cron script to make a movie out of webcam stills
#

# The webcam puts the images of the whole day into a folder with the date. This generates the target folder.
foldername=/home/ftpuser/labcam/$(date -d "-1 days" +%Y%m%d)
echo $foldername

# This renames the iamges into 1.jpg, 2.jpg, etc. This is necessary for ffmpeg to recognize them.
counter=1
for i in $foldername/*.jpg; do
new=$foldername/$counter.jpg
echo $new
cmd='mv $i $new'
eval $cmd
counter=$((counter+1))
done

# This does the actual conversion
ffmpeg -f image2 -framerate 25 -i $foldername/%d.jpg -c:v libx264 $foldername/out25.mp4

# And this removes the jpg files from the target folder (in order to save space)
cmd2='rm '$foldername'/*.jpg'
eval $cmd2