EasyPrev

@echo off
if "%~1"=="" goto error
if "%~2"=="" goto error
if "%~3"=="" goto error
if exist EasyPrev.txt del EasyPrev.txt
ffmpeg -hide_banner -ss %3 -i "%~1" -vframes 1 -c copy -an -y TEMP_EasyPrev_preview.webm
copy /Y %1 TEMP_EasyPrev_source.webm
echo file 'TEMP_EasyPrev_preview.webm'>nul>>EasyPrev.txt
echo file 'TEMP_EasyPrev_source.webm'>>EasyPrev.txt
ffmpeg -hide_banner -itsoffset 0.04 -i "%~1" -f concat -i EasyPrev.txt -map 1:v -map 0:a -c copy -y "%~2.webm"
del TEMP_EasyPrev_preview.webm
del TEMP_EasyPrev_source.webm
del EasyPrev.txt
goto exit
:error
echo ##### Error! #####
:exit
echo ##### Script End #####