Get aspect ratio of video from FFmpeg

Question

I am using FFmpeg to convert a video from one format to another. I need to extract the aspect ratio of the video first. How can I find that information?

Answer 1

To more directly answer the question that was asked, as well as get the data in the simplest format possible to be used for programmatic purposes (such as a variable):

$ ffprobe -v error -select_streams v:0 -show_entries stream=display_aspect_ratio -of default=noprint_wrappers=1:nokey=1 <yourfilename>
16:9

Unfortunately ffprobe's syntax is overly verbose, but thankfully that doesn't matter too much when running this sort of command from a script or program to capture the data into a variable or array.

Answer 2

ffprobe -v error -select_streams v:0 -show_entries stream=width,height,sample_aspect_ratio,display_aspect_ratio -of json=c=1 'filepath.mov'

this command will get width, height, sar and dar of the first video stream of file in json format.