I want to decrease a 1080p movie to 720p but I'm having problems with maintaining the correct aspect ratio. I was wondering if there was an application or something that would tell me what resolution would maintain the current aspect ratio of the movie I'm converting if I lower one of the dimensions. I haven't found an easy way to do this and the two fields aren't bound together to maintain the aspect ratio in my program. I'm using AutoMKV currently. Is there a better program for this or is there any way of having it tell me what the other number for the dimension should be if I decrease to 720?