being windows systems admin am, i'm getting around learning powershell. being said, have no idea i'm doing (surprise, surprise). i thought learning experience me play around powershell @ home, far away production environment. recently, i've begun using ffmpeg convert of .mkv files .mp4 have better playback support playstation 3 via plex, , thought learning experience. the command i've been running follows: ffmpeg -i oldvideoname.mkv -vcodec copy -acodec ac3 oldvideoname.mp4 what want have powershell script run once, scanning folder , sub-folders .mkv files (get-childitem ".*.mkv"), transcode them .mp4 via above command, , place them in same location .mkv same naming scheme. example of running script d:\videos target directory: d:\videos\home_dvr\movies\video1.mkv --> d:\videos\home_dvr\video1.mp4 d:\videos\home_dvr\tv\video2.mkv --> d:\videos\home_dvr\tv\video2.mp4 as can guess, can't figure out life of me. here's latest attempt...