I am rendering a composition of 640x360 in two output resolutions: non scaled (640x360) and 470x270 using H.264. The output files are the same size (15MB). How is that possible?
If you have the target bitrate set to the same amount for each movie, then the number of megabytes per second of video will be the same. What will be different is how aggressive the compression will be in the movie with the larger frame size to compress the movie into that data rate.