What is a variable frame rate?
Also called: VFR
Definition
A variable frame rate video does not space its frames evenly in time; it stores a new frame only when one is available.
Screen recorders often produce variable frame rate files, because a still screen gives them nothing new to capture. Players handle this well. Some video editors assume evenly spaced frames, which can make the sound drift out of sync with the picture.
Editing in the app that made the recording, or converting to a constant frame rate first, avoids the problem.
Related terms
- Frame rate
- Frame rate is the number of still pictures a video shows each second, measured in frames per second (fps).
- Keyframe
- In video compression, a keyframe is a frame stored as a complete picture; the frames between keyframes store only what changed.
- Rendering
- Rendering is producing the final video file from an edit: drawing every frame with its effects and encoding the result.