create movie from one image updates in linux - c

Question

I'm a C programmer on linux.
I write a program that saves an image in /srv/ftp/preview.png which is updating frequently and i want to create a movie from this updates.
It's timestamp is important for me, e.g if image updates after 3.654 seconds i want movie show this update(frame) after 3.654 seconds too.
I searched in Internet for several hours but i can't find any solution.
I know about ffmpeg but it will convert images(and not one image) to movie without millisecond timestamp.
I found this Question but it seems is not useful in this case.
Is there any tool to do that? if not, please introduce an API in c to write a program myself

Answer 1

You can try to use inotify watch modification on the file and ffmpeg to append file to the movie:
#!/bin/bash
FRAMERATE=1
FILE="/path/to/image.jgp"
while true
do inotifywait -e modify "$FILE"
echo "file changed"
# create temp file name
TMP=$(mktemp)
# copy file
cp "$FILE" "$TMP$
# append copy file to movie
# from https://video.stackexchange.com/q/17228
# if movie already exist
if [ -f movie.mp4 ]
then
# append image to a new movie
ffmpeg -y -i movie.avi -loop 1 -f image2 -t $FRAMERATE -i "$TMP".jpg -f lavfi -t 3 -i anullsrc -filter_complex "[0:v] [1:v] concat=n=2:v=1 [v] " -map "[v]" newmovie.avi
# replace old by new movie
mv newmovie.mp4 movie.mp4
else
#create a movie from one image
ffmpeg -framerate 1 -t $FRAMERATE -i "$TMP" movie.mp4
fi
rm "$TMP"
done
This script must certainly be adapted, (in particular if your framerate is high) but I think you can try to play with it.
One bad thing also that the movie creation will become slower and slower because the movie becomes bigger.
You should to store images of a certain time duration in a directory and convert all at once (like once an hour/day)
If you want to serve a stream instead of creating a video file, you can look at https://stackoverflow.com/a/31705978/1212012