Script to add a scrolling watermark and scaling a video in one go using `ffmpeg`

watermark.bash

#!/bin/bash

dir=$(pwd)

(cd $1
mkdir -p output

for i in * 
do
    output="output/$(echo $i | sed 's/\..*$/\.mp4/')"
    T=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$i")
    HEIGHT=$(ffprobe -v error -show_entries stream=height -of default=noprint_wrappers=1:nokey=1 "$i")

    ffmpeg -i "$dir/logo.png" -y -v quiet -vf scale=-1:$HEIGHT/12 "$dir/scaled.png"

    ffmpeg -i "$i" -i "$dir/scaled.png" -filter_complex "overlay=((W-w)/$T)*t:100,scale=-1:240" "$output"
done
)