DIVIDE the WIDTH of your SOURCE footage (1920 in this example) by the final aspect ratio desired (2.35 in this example). So, 1920. DIVIDED BY 2.35 = 817 pixels ...
1920 x 1080. 1.85, 1920 x 1038. 1.90, 1920 x 1010. 2.00, 1920 x 960. 2.35, 1920 x 816. 2.37, 1920 x 810. 2.39, 1920 x 802. 2.40, 1920 x 800. 2.44, 1920 x 786 ...
2.35:1 was used in films prior to 1970 and 2.40:1 is an incorrect rounding ... (i.e. Blu-ray @ 1920x800, 2KDCP @ 2048x858, 4KDCP @ 4096x1716 etc.). It always ...