aspectRatio property
The display aspect ratio of the video in the output file. Valid values
include:
auto, 1:1, 4:3, 3:2,
16:9
If you specify auto, Elastic Transcoder tries to preserve the
aspect ratio of the input file.
If you specify an aspect ratio for the output file that differs from aspect ratio of the input file, Elastic Transcoder adds pillarboxing (black bars on the sides) or letterboxing (black bars on the top and bottom) to maintain the aspect ratio of the active region of the video.
Implementation
final String? aspectRatio;