Burn subtitles into a video, also called hardcoding or open captions: the text of each cue is drawn into the frames themselves, so it shows in every player and cannot be switched off. The style is fixed: bold white sans-serif with a black outline, centred, wrapped at 90% of the frame width, in three sizes scaled to the frame height. Every frame is decoded and re-encoded on your device, to H.264 in an MP4 where your browser can encode it and to WebM otherwise. The audio track is copied as it is, without re-encoding.
How it works
- Drop a video and its .srt or .vtt subtitle file, up to 15 minutes of video per file.
- Choose size S, M or L (4%, 5.5% or 11% of the frame height) and top or bottom placement, and check the result on the preview frame.
- Burn in & download. Cancel stops the encode and saves nothing; let it finish and the file keeps the original resolution, frame rate and audio.
Questions
- Does burning in subtitles reduce video quality?
- Slightly, because the video is decoded and encoded again, and there is no way to draw into the frames without doing that. The encoder targets a bitrate set from the resolution and frame rate, about 7.5 Mbps for 1080p at 30 fps and 3.3 Mbps for 720p at the same rate, and keeps the original dimensions. The audio is not re-encoded at all.
- Can I change the subtitle font or colour?
- No. Burned captions use one style: bold white sans-serif text with a black outline, centred. You choose the size and whether it sits at the top or the bottom. Formatting tags such as <i> and <b> are removed from the drawn text, and VTT positioning settings are ignored. If you need custom styling, keep a separate subtitle file, where the player does the rendering.
- Can I burn in translated subtitles?
- Yes. Translate the .srt or .vtt first with the Translate mode of the same tool and read it through. Then switch to Burn in and drop the video together with the translated file you downloaded, not the original. One caveat for Japanese and Chinese: the renderer wraps lines at spaces, so put line breaks into long cues yourself. Languages that put spaces between words wrap on their own.
- Does my file get uploaded?
- No. The models and all processing run inside your browser on your own device. You can verify this yourself: open your browser’s DevTools, watch the Network tab, and process a file: there are no uploads. After the first visit most tools also work fully offline.
- What is a two-point resync?
- A fixed shift fixes subtitles that are uniformly early or late, but not ones that drift further out over the runtime (a frame-rate mismatch). Pin the first and last line to their correct moments and every cue between them is stretched linearly. That is the standard fix, done locally.
- How does on-device translation work?
- Recent Chromium browsers ship a built-in translator that downloads language packs and runs locally. Where your browser offers it, this tool uses it, subtitle text included, and nothing is sent to a service. Where it does not, the page says so instead of quietly uploading.
- Burned-in vs a subtitle file: which do I want?
- A separate .srt/.vtt can be toggled and edited, and players render it crisply, so prefer it where you control playback. Burn-in re-encodes the video with the text drawn into the frames: it plays everywhere and cannot be turned off.