section_path: Sets/Display resolution/SD
section_name: SD
paragraph_text: SD
  
  Standard-definition television or SDTV refers to two different resolutions: 576i, with 576 interlaced lines of resolution, derived from the European-developed PAL and SECAM systems, and 480i based on the American National Television System Committee NTSC system. SDTV is a television system that uses a resolution that is not considered to be either high-definition television (720p, 1080i, 1080p, 1440p, 4K UHDTV, and 8K UHD) or enhanced-definition television (EDTV 480p). In North America, digital SDTV is broadcast in the same 4:3 aspect ratio as NTSC signals, with widescreen content being center cut. However, in other parts of the world that used the PAL or SECAM color systems, standard-definition television is now usually shown with a 16:9 aspect ratio, with the transition occurring between the mid-1990s and mid-2000s. Older programs with a 4:3 aspect ratio are shown in the United States as 4:3, with non-ATSC countries preferring to reduce the horizontal resolution by anamorphically scaling a pillarboxed image.