Converting from one TV system to another
Main article: Television standards conversion
Converting between different numbers of lines and different frequencies of fields/frames in video pictures is not an easy task. Perhaps the most technically challenging conversion to make is from any of the 625-line, 25-frame/s systems to system M, which has 525 lines at 29.97 frames per second. Historically this required a frame store to hold those parts of the picture not actually...
