twotalesanimation
79 lines
2.7 KiB
TypeScript
79 lines
2.7 KiB
TypeScript
/**
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* Frame-accurate utilities for VFX review.
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* All frame calculations use 0-based frame numbers
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* unless documented otherwise.
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*/
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/** Convert frame number to video currentTime in seconds */
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export function frameToTime(frame: number, fps: number): number {
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return frame / fps;
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}
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/** Convert video currentTime to frame number (0-based) */
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export function timeToFrame(time: number, fps: number): number {
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return Math.floor(time * fps);
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}
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/** Format a frame number as a timecode string: MM:SS:FF */
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export function frameToTimecode(frame: number, fps: number): string {
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const totalSeconds = frame / fps;
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const hours = Math.floor(totalSeconds / 3600);
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const minutes = Math.floor((totalSeconds % 3600) / 60);
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const seconds = Math.floor(totalSeconds % 60);
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const frames = frame % Math.round(fps);
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if (hours > 0) {
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return `${String(hours).padStart(2, "0")}:${String(minutes).padStart(2, "0")}:${String(seconds).padStart(2, "0")}:${String(frames).padStart(2, "0")}`;
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}
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return `${String(minutes).padStart(2, "0")}:${String(seconds).padStart(2, "0")}:${String(frames).padStart(2, "0")}`;
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}
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/** Format a raw time (seconds) as MM:SS.mmm */
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export function timeToDisplay(time: number): string {
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const minutes = Math.floor(time / 60);
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const seconds = Math.floor(time % 60);
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const ms = Math.floor((time % 1) * 1000);
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return `${String(minutes).padStart(2, "0")}:${String(seconds).padStart(2, "0")}.${String(ms).padStart(3, "0")}`;
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}
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/** Given duration and fps, compute total frame count */
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export function durationToFrameCount(duration: number, fps: number): number {
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return Math.floor(duration * fps);
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}
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/** Clamp a frame number to [0, totalFrames - 1] */
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export function clampFrame(frame: number, totalFrames: number): number {
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return Math.max(0, Math.min(totalFrames - 1, frame));
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}
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/** Step a single frame forward or backward */
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export function stepFrame(
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currentFrame: number,
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delta: number,
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totalFrames: number
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): number {
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return clampFrame(currentFrame + delta, totalFrames);
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}
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/** Convert a timeline position (0-1) to frame number */
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export function positionToFrame(position: number, totalFrames: number): number {
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return clampFrame(Math.floor(position * totalFrames), totalFrames);
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}
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/** Convert a frame number to timeline position (0-1) */
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export function frameToPosition(frame: number, totalFrames: number): number {
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if (totalFrames === 0) return 0;
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return frame / totalFrames;
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}
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/** Common VFX frame rates */
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export const COMMON_FPS = [23.976, 24, 25, 29.97, 30, 48, 50, 59.94, 60] as const;
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export type CommonFPS = (typeof COMMON_FPS)[number];
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/** Human-readable fps label */
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export function fpsLabel(fps: number): string {
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if (fps === 23.976) return "23.976";
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return String(fps);
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}
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