Search, Thumbnails and video streaming

Search files through out the machine without creating much load on the cpu. Wanted to build a utility; which will give the OS level thumbnail file of an image type file (jpb,bmp,gif,tiff,jpe,heic,.nef). Wanted to build a utility: which can convert any video file(mp4,wmv,avi,mov,mts,m4v,vob) to MP4 stream on the fly without creating heavy load on CPU and play in HTML5 player.