TikTok Fix Pack makes tiktok.com work properly in Firefox. Several fixes in one lightweight extension, with no data collection and no network access. Fix 1 — Smooth video playback TikTok serves HEVC (H.265) streams to Firefox whenever the browser reports codec support. On many systems this pipeline stutters, drops frames, or lags after a few videos in the feed. The extension reports HEVC (and optionally AV1) as unsupported, so TikTok falls back to rock-solid H.264. Fix 2 — No more double audio The TikTok web feed keeps several <video> elements in the DOM at once. Sometimes a hidden video never gets paused and keeps playing in the background, causing overlapping, out-of-sync, "demon-voiced" audio. A built-in watchdog detects these zombie videos and pauses them. Videos that repeatedly resist pausing get their media pipeline destroyed completely. Fix 3 — Responsive DMs After scrolling deep into a conversation, TikTok keeps hundreds of messages in the DOM and re-renders the whole chat on every keystroke, making typing lag badly. Off-screen message groups are excluded from layout and painting, and TikTok's per-keystroke draft writes are debounced into a single update, so the composer stays fast even in huge chats. Fix 4 — Smooth feed Mouse movement over feed video overlays triggered constant full-page style recalculations and stutter. Overlay repaints are now contained. Settings (click the toolbar icon): - Block HEVC — recommended, on by default - Block AV1 — optional, forces H.264 even harder - Single playback watchdog — on by default - Strict mode — pause every other video on each playback start - Zombie pipeline destruction threshold - DM rendering hints — on by default - DM draft fix — debounces TikTok's per-keystroke draft writes, on by default - DM contain mode — alternative rendering isolation - Calm live region — silences chat screen-reader announcements - Reduce hover repaint — on by default - Debug logging for troubleshooting Permission note: on install Firefox asks for access to tiktok.com — this is required for the fixes to run on the page. Choose "Allow" so they work automatically on every visit. Privacy: the extension runs only on tiktok.com, stores settings locally in your browser, collects nothing, and contacts no servers. TikTok is a trademark of TikTok Pte. Ltd. This extension is not affiliated with or endorsed by TikTok.