to split your files in specific output size, cut any video clip from a video file, sync audio in video properly,aspect ratio,tags in a video , extract & combine audio video or it is matter of combine multiple video into one video "MKV ToolNix" is the best option
official site:https://mkvtoolnix.download/downloads.html
alternative 1:http://ceesty.com/wuCCBR
alternative 2:http://ceesty.com/wuCCme
