Vertical video platforms and video search engines enforce strict interface geometry and metadata parsing rules that are not visible inside a standard timeline monitor. On TikTok, Instagram Reels, and YouTube Shorts, persistent navigation bars, account handles, audio tickers, and engagement buttons cover up to 35 percent of a 1080x1920 frame, frequently obscuring burned-in subtitles or lower-third graphics. On long-form uploads, YouTube disables automatic video chapters if a single timestamp in the description violates chronological order, omits the mandatory 00:00 start marker, or falls below the 10-second minimum chapter duration. The tools in this category let editors inspect 9:16 still frames against calibrated platform occlusion masks on an HTML5 canvas and validate chapter timestamp lists line by line prior to publication.
Upload a 9:16 frame or test composition on an interactive HTML5 canvas to check whether captions and graphics are occluded by TikTok, Instagram Reels, or YouTube Shorts UI buttons.
Validate YouTube description chapter lists against all official parser rules (00:00 start, minimum 3 chapters, 10-second minimum length, chronological order) and auto-format clean output.
Pixel-level reference coordinates for 1080x1920 vertical timelines so burned-in subtitles, lower thirds, and product callouts never sit behind platform UI buttons.