SubSync — custom subtitle loader

Load your own .srt/.vtt/.sup subtitles onto HBO Max. Timing and position controls, fully local and private.

SubSync overlays your own subtitle files onto the video player at max.com (HBO Max), with sync and position controls built in. Everything runs locally in your browser: subtitle files are read with the File API and are never uploaded, transmitted, or shared. FEATURES • Text subtitles (.srt / .vtt) with clean, high-contrast styling • Blu-ray PGS image subtitles (.sup) — renders the original bitmaps with authored colors, styling, and positioned effects intact, including smooth animated karaoke/FX tracks frame-locked to the video • Timing controls — nudge subtitles ±0.05s / 0.1s / 0.5s with on-screen buttons or keyboard; remembered per file • Vertical shift — move dialogue subtitles into the letterbox bar in fullscreen; positioned effect subtitles stay anchored to the scene • Fullscreen-safe — subtitles and controls keep working in fullscreen • Persistent — your file and settings survive reloads (large .sup files are stored locally in IndexedDB) HOW TO USE Open any title on max.com and start playback. Click "📄 Subs" in the bottom-left widget and choose your subtitle file. Adjust timing with the buttons or hotkeys: [ ] = ±0.1s, { } = ±0.5s, G/H = ±0.05s, Shift+↑/↓ = vertical position. PRIVACY SubSync collects no data whatsoever. No analytics, no accounts, no network requests. Your subtitle files never leave your device. SubSync is not affiliated with or endorsed by HBO Max or Warner Bros. Discovery. It displays only subtitle files you provide and distributes no content.