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?

Simple math? You need to know what the ratio is to start with before you can do anything - 1080p doesn't tell you anything other than the vertical resolution. But if you knew the horizontal resolution - let's say 1920, then you can do the math: 1920/1080 = 16:9 or 1.78. Plug in your new vertical: x/720 = 1.78 Solve for x = 1.78 x 720 x = 1280

Alright, I was trying to do something like that with cross multiplication but it wasn't workin so hot for me. I didn't even think to solve using the aspect ratio itself. Thanks for being gentle in my stupidity.