The numbers (24, 25, 30, 50 and 60) represent how many times the video frame is displayed per second. The letters indicate if the video frame is displayed using an interlaced (i) or progressive (p) format.
Progressive video content displays both the even and odd scan lines (the entire video frame) at the same time.
Interlaced video displays even and odd scan lines as separate fields; the even scan lines are drawn on the screen, then the odd scan lines are drawn on the screen. Two of these even and odd scan line fields make up one video frame.
- The 24p video frame rate is closer to that of film in theatrical motion pictures.
- The video frame rates 50i and 60i are recommended for normal recording.
- The 25p video frame rate is used in countries outside of the United States and Canada.
- The 50p video frame rate has double information per unit time.