Managing mixed HD and SD broadcasting

TV program material is produced in various formats with diverse image aspect ratios. SDTV image usually has 4:3 aspect ratio, while HDTV image has an aspect ratio of 16:9. To ensure proper display of content on different display devices, there are methods for conversion between different formats. Also, there are methods of transmitting information about aspect ratio to the TV receivers, which allows them to switch to the correct display mode. It is necessary to make some compromises to manage image aspect ratio conversion and display the converted image. These include distortion of the image or parts of the image, losing parts of the image, or leaving parts of the screen unused and filled with black patterns.