mkshort is a small go tool to create short videos containing
a diaporama of images with overlayed text, via ffmpeg(1).
The input is a text file like this one:
# Specify an audio file with fade-in/out of 4sec both; skip the first 2sec
@2 4 4 BMC19T1VivaldiSeasonsSpring.mp3
:virgin-of-the-rocks-paris.jpg
0.7 3.5
Here is what seems \\
to be \\
a little-known fact \\
...
+0.7 3
Jesus, the \\
bottom right child \\
+0.7 5
Is the only one \\
looking at the \\
\textit{Source of Light} \\
\emoji{face-in-clouds} \\
...
:virgin-of-the-rocks-london.jpg
+0.7 4
This also holds in the \\
"London" version of the \\
painting \\
+0.7 2
The previous .gif was generated with ffmpeg(1) from
the .mp4:
$ ffmpeg -y -i virgin-of-the-rocks.mp4 virgin-of-the-rocks-audio.gif
A video with sound is available here or here.
While ffmpeg(1) provides a text overlay filter, it can be limited. Instead, we're using LaTeX (LuaLaTeX) to provide a more complete features set (colored emojis (.pdf), mathematical typesetting, etc.).
A quick man page is available: mkshort(1). An old, semi-automatic
awk(1)/sh(1)-based prototype is available in
old/prototype.sh. A "Virgin of the rocks" example
is provided. Quick help:
$ make help
Available targets:
mkshort : build mkshort
all : build mkshort; run tests
clean : removed compiled files
tests : run automated tests
example : display the ffmpeg(1) command,
build (a bit slow) and play the example.
install : install to /bin/ andqq /usr/share/man/man1/
uninstall : remove installed files
$ mkshort -help
Usage of mkshort:
-b string
rescale padding color (default "black")
-c string
LaTeX command, splitted on spaces (default "lualatex")
-d string
cache directory (default "/home/mb/.mkshort")
-e string
extension for the compiled text images (default ".png")
-f string
output pixel format (default "yuv420p")
-h int
output height (default 1920)
-i string
text indentation (default "\t")
-l string
shell to run the compiled ffmpeg(1) command (default "/bin/sh")
-m Enable/disable faststart (default true)
-p string
LaTeX template (path)
-r int
output framerate (default 30)
-s float
default waiting time between text (default 0.8)
-t string
LaTeX template (string) (default "\\documentclass[preview,convert={density=600,outext=.png,command=\\unexpanded{ {\\convertexe\\space -density \\density\\space\\infile\\space \\ifx\\size\\empty\\else -resize \\size\\fi\\space -quality 90 -trim +repage -background \"rgba(50,50,50,0.5)\" -bordercolor \"rgba(50,50,50,0.5)\" -border 25 -flatten \\outfile} } }]{standalone}\n% Requires lualatex\n\\usepackage{emoji}\n\n\\usepackage{xcolor}\n\\usepackage{amsmath}\n\\begin{document}\n\n\\begin{center}\n\\textcolor{white}{ {{ .text }} }\n\\end{center}\n\\end{document}\n")
-w int
output width (default 1080)
-x Compiled command printed, not ran
-y Allow automatic output overwrite (default true)