One feature I really miss from Linux and not only digikam itself, is the ability to create time lapse videos from photographs easily.

After some intensive search and work, I found my way to create time lapse videos, but I need the console and a few manual steps that probably would be easy to be implemented as a new feature in digikam (probably by a Google Summer of Code project assigned to a student? :) ).

Step 1:
First you need to put all of the pictures in a folder that you will work with (In digikam you should get a window with some options on either to choose the photos one by one, or a folder and all of its contained images).

Step 2:
You need create a text file and put the filenames in the right frame order and sometimes when the time your camera reaches the final file like DSC_9999.jpg, it will start from DSC_0001.jpg again so this might not be trivial in specific cases. So digikam should read the exif an put the photographs in order according to their creation date.

Step 3:
The photographs must be resized to the desired output video resolution. For example if you want to create a FullHD 1920x1080 video, but your photos are 18Mpixels, first you need to resize the pictures otherwise you will get much unnecessary processing time. The plugin should give the option to the user to keep the aspect ration or not.

Step 4:
Optionally you might want change the levels, brightness, contrast, saturation, curves or sharpen all of the photographs to promote some details and enhance the photos, so some batch processing should be done here similar to the recording functionality of Photoshop but much simpler. Ideally open the first photo in showfoto, make some limited changes, and perform these to the rest of the photos being part of the time lapse

Step 5:
The photographs will usually have some flickering because even if you choose a fixed shutter speed, this might not be exact for each photograph taken, due to the mechanical parts of the camera (If 1/200s is chosen as the shutter speed, first photo might 1/199s and the one after might 1/202s). In this case the final time lapse video will be flickered. Optional deflickering with some options chosen by the user (for example the rolling window averages for luminance calculation for each photo) should take process.

Step 6:
Create a quick preview of the video and show it to the user.

Step 7:
Choose the codec to compile the time lapse video and save it.

This would give much value to digikam, and the whole open source Linux world as I haven't found a tool to perform these simple tasks with a nice graphical user interface.

The way I perform these steps now is the following:

Resize the images first to 1920x1080 (all of the rest of the operations will be much much faster)

Resize pictures:
# cd source_folder_of_pictures
# mkdir resized
# mogrify -path resized -resize 1920x1080! *.jpg

Use ls to sort the files by their filename.
# cd resized
# ls -1 | grep -v files.txt > files.txt

Use mencoder to combine all of the photos in one video without losing quality!
WARNING: Use ONLY ONE of the following 3 commands
TIP: I usually choose the first one to quickly check the result and then I re-make the video with the second or third command if I want to make some post processing in kdenlive.

Command 1 # mencoder -nosound -noskip -oac copy -ovc copy -o test.avi -mf fps=15 'mf://@files.txt' <- Very fast but does not create index so if you want to edit with a non linear editor do not choose this.

Command 2 # mencoder -idx -nosound -noskip -ovc lavc -lavcopts vcodec=mjpeg -o test.avi -mf fps=25 'mf://@files.txt' <- Fast, it will create index, but it will re-compress the JPG files so some loss of quality will occur (insignificant, so you can safely bet on this) 

Command 3 # mencoder -idx -nosound -noskip -ovc lavc -lavcopts vcodec=ljpeg -o test.avi -mf fps=25 'mf://@files.txt' <- Slow, it will create index, it will re-compress the JPG file but with the highest quality options to provide lossless results (the final file will be larger than the total of the original files, but if you are a quality freak, then go for this one)


Use ffmpeg to compress the video.
# avconv -i test.avi -c:v libx264 -preset slow -crf 15 output-final.mkv

Check here for more encoding options: https://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide

To perform the two optional steps:
Step 4: I use photoshop in wine and the record functionality
Step 5: I have made my own perl script that uses imagemagick to calculate luminance of each photo, calculate the new luminance for each photo with rolling averages and eventually change the luminance for each photo (https://www.youtube.com/watch?v=SNfq__chC5M).

Reproducible: Always