/**
 * Modular FFmpeg filter fragments for the Songs2VID brand watermark overlay.
 * Always bottom-right with padding; scales to a fraction of frame width.
 */
export function buildBrandWatermarkOverlayFilters(options: {
  baseLabel: string;
  watermarkInputIndex: number;
  watermarkWidthPx: number;
  offsetX?: number;
  offsetY?: number;
  outLabel?: string;
}): string[] {
  const ox = options.offsetX ?? 20;
  const oy = options.offsetY ?? 20;
  const out = options.outLabel ?? "vout";
  return [
    `[${options.watermarkInputIndex}:v]scale=${options.watermarkWidthPx}:-1[wm]`,
    `[${options.baseLabel}][wm]overlay=W-w-${ox}:H-h-${oy}[${out}]`,
  ];
}