NTSC and PAL are formats used for displaying videos. The main differences between the two formats are based on their electrical differences, resolution quality and the rate at which broadcasts are displayed.

HD and Full HD are formats used for broadcasting image and video content on various multimedia devices. A significant difference between would be their respective resolutions.

Both qHD and QHD are popular HD viewing formats. However, the differences between the two are not as subtle as the capitalization of an alphabet in their titles.

Both qHD and HD are formats used to display high quality images on an HD enabled screen. However, both these formats differ in their resolutions and coverage of devices.

qHD stands for quarter high definition, and is one fourth of full high definition, or full HD, hence the name qHD. Both these resolutions differ in terms of their measurement as well.