Add or subtract from a timecode, either another timecode (b) or a raw frame count (frames), at a given frame rate. Uses frame-exact SMPTE math (including drop-frame). A result below zero is rejected as a clean 400.

Rebase a timecode (or a raw frame count) from one frame rate to another on a real-time basis, so the wall-clock position is preserved. Give a source frameRate plus timecode or totalFrames, and a toFrameRate (with optional toDropFrame). Returns the target timecode, frame count and seconds.

Parse an SMPTE timecode (HH:MM:SS:FF, or HH:MM:SS;FF for drop-frame) at a given frame rate into its components, total frame count and real-time seconds. Drop-frame is auto-detected from a ';' separator unless dropFrame is set. Out-of-range or non-existent drop-frame values are a clean 400.