What is a Drop frame?
Drop frame is a technique used in film and video production to compensate for the discrepancy between the actual time elapsed and the time code displayed. It is a method of counting the time that was developed for NTSC video, which operates at 29.97 frames per second (fps) instead of the more accurate 30 fps. Drop frame is used to ensure that the time code stays in sync with real-time, especially when the video is edited or synchronized with audio.
How does a Drop frame timecode work?
Drop frame timecode is a technique used in film and video production to keep the timecode in sync with the actual time. It works by dropping specific frame numbers from the timecode count, namely frames 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 of every minute (except for every 10th minute), which would have been counted if the frame rate were exactly 30 fps.
By skipping these frames, the drop frame timecode stays accurate with the actual time while still counting every video frame. This technique is used to synchronize the timing of audio and video recordings.
Drop frame vs. Non-drop frame
- Frame rate: Drop frame timecode is used with NTSC video, which operates at 29.97 frames per second (fps), while non-drop frame timecode is used with PAL video, which operates at 25 fps. Non-drop frame timecode counts every frame, while drop frame timecode drops certain frames to account for the discrepancy between 29.97 fps and 30 fps.
- Method of counting time: Drop frame timecode drops certain frames to ensure that the timecode stays in sync with real-time, while non-drop frame timecode counts every frame without dropping any frames. Drop frame timecode is used in applications where frame accuracy is critical, such as video and film production, while non-drop frame timecode is used in applications where frame accuracy is not as critical, such as in some types of animation and computer-generated imagery.
- Timecode format: Drop frame timecode is represented by a semi-colon (;) between the seconds and frames, while non-drop frame timecode is represented by a colon (:). This difference in format helps to distinguish between the two types of timecode.
- Applications: Drop frame timecode is commonly used in video and film production to ensure that the timecode stays in sync with real-time, especially when the video is edited or synchronized with audio. It is also used in broadcast television and multimedia production. Non-drop frame timecode, on the other hand, is used in PAL video and in applications where frame accuracy is not critical.