TikTok 4K video uploader

TikTok recompresses every upload and usually keeps a lower quality than the file you sent. A high-bitrate H.264 file survives that step with fewer artifacts.

It re-encodes the clip in your browser (H.264, high bitrate) and appends a short run of tiny empty samples to the end of the video track. Picture and sound are not touched by that step. In our tests TikTok then kept a higher quality and bitrate than for a plain upload. TikTok does not document why, so treat it as a workaround.

No. It depends on TikTok, on how you publish and on your device. The extra data can make some players or editors open the file badly. If that happens, use a normal export.

Only if your source is 120 fps. For 30 or 60 fps clips the frames are repeated, so the file is marked 120 fps but motion does not get smoother.

Zernio is a separate service that posts to TikTok for you. You create the key in your own Zernio account and paste it here. It is used in this browser to call zernio.com and Clip4K has no server to send it to. Without "Remember" it is forgotten when you close the tab. You can delete the key in Zernio at any time. Use a computer or phone you trust.

No. Processing happens inside your browser. The video leaves your device only if you choose to publish it to TikTok through your own Zernio account.

The video is processed by your own device. For long 4K clips use a computer, or pick 1080p.