Recently I came around to try the time-lapse feature of my shiny new “GoPro Hero 3″ cam.
I set it up to take a picture every two seconds and I ended up with around 20 000 photos after about 15 hours. (Thank you, Christoph )
Picture Specs: Width: 2592 pixels; Height: 1944 pixels; Exposure Time: 1/2 sec.

Re-size
After importing them into a single folder I decided to re-size them (make sure to keep the aspect ratio, check it here: aspect ratio calculator).

mogrify -resize 2048x1536! *.JPG

This command re-sizes all pictures to 2048×1536 – make sure to keep the originals

Create a file which contains the names of all photos
In order to have the correct order of your photos create a file containing all names of the photos.

ls -1tr | grep -v files.txt > files.txt

create avi file
With the following command you get a avi file (mjpeg codec) with 25fps

mencoder -idx -nosound -noskip -ovc lavc -lavcopts vcodec=mjpeg -o output.avi -mf fps=25 'mf://@files.txt'

create mkv
Now convert the avi to mkv

avconv -i output.avi -c:v libx264 -preset slow -crf 15 output-final.mkv

Credits go to “CyberAngel” who wrote a great posting here: http://ubuntuforums.org/showthread.php?t=2022316&p=12091502#post12091502