@echo off

rem folder structure:
rem folder/
rem   - script.bat
rem   - logo.png
rem   - vids/
rem   - results/

rem === input ===
set inputdir=vids
set outputdir=results
set start=2
set end=1
set overlay="[0:v][1:v]overlay=10:10"

mkdir %outputdir%
for /f "delims=" %%f in ('dir /b "%inputdir%\*.mp4"') do (

    rem === get video duration ===
    ffprobe -v error -show_entries format=duration -of "default=nw=1:nk=1" %inputdir%\%%f > temp.txt
    set /p duration=<temp.txt
    set /p tduration=<temp.txt
    set /A "tduration-=%start%+%end%"

    ffmpeg -i %inputdir%\%%f -i logo.png -t %start% -filter_complex %overlay% -y part_start.mp4
    ffmpeg -sseof -%end% -i %inputdir%\%%f -i logo.png -filter_complex %overlay% -y part_end.mp4
    ffmpeg -i %inputdir%\%%f -ss %start% -t %tduration% -c copy -y part_middle.mp4
    echo file 'part_start.mp4' > temp.txt
    echo file 'part_middle.mp4' >> temp.txt
    echo file 'part_end.mp4' >> temp.txt
    ffmpeg -f concat -safe 0 -i temp.txt -c copy -y %outputdir%\%%f
)
del temp.txt