Understanding Aspect Ratios. What is an aspect ratio? Have you ever wondered why some things you watch on television have black bars around the picture? - ppt download
Amazon.com: O Rebu (2014) (Dir. Jose Luiz Villamarim) (Box) - Patricia Pillar / Tony Ramos / Daniel de Oliveira : Movies & TV
Figure 3 from Automatic letter/pillarbox detection for optimized display of digital TV | Semantic Scholar
Letter Box vs. Pillar box by Renz Henry Emilanan
What you need to know about Aspect Ratios and Letterboxing