Framerates, otherwise known as FPS (Frames Per Second) refer to the number of individual images (frames) displayed per second in a video. The choice of framerate depends on the intended delivery format and the desired aesthetic. Common FPS values include:
24 FPS: The standard frame rate for film, providing a cinematic look
25 FPS: The frame rate for PAL (Phase Alternating Line) video, used in many European countries
29.97 FPS: The frame rate for NTSC (National Television System Committee) video, used in North America and Japan
30, 50, and 60 FPS: Higher frame rates used in high-definition video and gaming for smoother motion
The choice of FPS affects the perceived smoothness of motion, the file size of the video, and the overall look and feel of the final product.
PAL, NTSC, SECAM, and HDTV are different video standards used in various parts of the world:
PAL (Phase Alternating Line) is a color encoding system used in most European countries, Australia, and parts of Asia. It has a frame rate of 25 fps and 576 visible lines of resolution.
NTSC (National Television System Committee) is a color encoding system used in North America, Japan, and parts of South America. It has a frame rate of 29.97 fps and 480 visible lines of resolution.
SECAM (Sequential Color with Memory) is a color encoding system used in France, Russia, and some African countries. It has similar specifications to PAL.
HDTV (High-Definition Television) is a digital video standard with higher resolution and aspect ratios compared to PAL, NTSC, and SECAM. HDTV formats include 720p, 1080i, and 1080p, with frame rates of 24, 25, 30, 50, or 60 fps.
Frame rate and frame duration are related concepts in video and film:
Frame rate is the number of frames displayed per second (FPS), which determines the temporal resolution and perceived smoothness of motion in a video or film.
Frame duration is the amount of time each individual frame is displayed on the screen, measured in seconds or milliseconds. Frame duration is the reciprocal of frame rate.
For example, at 24 FPS, each frame has a duration of 1/24 seconds (approximately 41.67 milliseconds). At 30 FPS, each frame has a duration of 1/30 seconds (approximately 33.33 milliseconds). Understanding the relationship between frame rate and frame duration is essential for tasks such as frame-accurate editing, motion graphics, and visual effects work.
23.98 fps and 24 fps are two different frame rates used in film and video production. 24 fps is the standard frame rate for film, while 23.98 fps is a slightly slower frame rate used to facilitate the conversion of film to NTSC video. The 23.98 fps frame rate is derived from the NTSC video frame rate of 29.97 fps by applying a 2:3 pulldown, which creates a telecine that can be easily converted to NTSC video. The difference between the two frame rates is small but can be noticeable in certain situations, such as when synchronizing sound or performing frame-accurate editing.
Video frame rate conversion is the process of changing the number of frames per second (FPS) in a video to match a different output format or to achieve a specific artistic effect. This process involves generating new frames or removing existing ones to create a smooth transition between the original and target frame rates. There are several methods for frame rate conversion, each with its own advantages and disadvantages.
One common method is called frame blending, which creates new frames by averaging the pixels from adjacent frames. This technique can result in smoother motion but may cause some loss of detail and sharpness. Another approach is frame interpolation, which analyzes the movement between existing frames and generates intermediate frames to create a more fluid motion. This method can preserve more detail but may introduce artifacts or "ghosting" in fast-moving scenes.
In some cases, frame rate conversion may simply involve duplicating or removing frames to achieve the desired FPS. This method, known as frame duplication or deletion, is less computationally intensive but can result in jerky or uneven motion, especially when converting between frame rates with significantly different cadences.
The choice of frame rate conversion method depends on factors such as the original and target frame rates, the desired output quality, and the available processing power. It's important to note that frame rate conversion can affect the overall look and feel of the video, and some methods may introduce artifacts or alter the intended motion characteristics. Whenever possible, it's best to capture and edit video at the desired output frame rate to minimize the need for conversion and maintain the highest possible quality.
Pull-down is a technique used to convert film frame rates to video frame rates, particularly when transferring 24 FPS film to 29.97 FPS NTSC video or 25 FPS PAL video. The process involves repeating or "pulling down" certain frames of the film to create a new video frame sequence that matches the desired video frame rate.
The most common pull-down methods are:
1. 2:3 pull-down (also known as 3:2 pull-down):
- Used to convert 24 FPS film to 29.97 FPS NTSC video.
- Each film frame is alternately held for 2 or 3 video fields, creating a repeating pattern of 2 fields, 3 fields, 2 fields, 3 fields, etc.
- This results in a slight "stuttering" effect known as "judder," which is more noticeable in scenes with slow, steady motion.
2. 2:2 pull-down:
- Used to convert 24 FPS film to 25 FPS PAL video.
- Each film frame is held for 2 video fields, effectively speeding up the playback by 4%.
- This results in a slightly shorter runtime and a slightly higher audio pitch compared to the original film.
Pull-down is necessary because film and video have different native frame rates, and displaying film directly at video frame rates would result in flickering and other visual artifacts. By using pull-down techniques, the film can be converted to a compatible video frame rate while maintaining acceptable visual quality.
In recent years, with the advent of digital cinema and progressive-scan video formats, pull-down has become less common, as films can now be shot and displayed directly at their native 24 FPS frame rate without the need for conversion to video frame rates.
Framerate (Wikipedia)
PAL (Wikipedia)
NTSC (Wikipedia)
HDTV (Wikipedia)