Caption Burn-In Studio

Knowledge Base

Hardcoded Captions vs. Soft Subtitles

Hardcoded (burned-in) captions are drawn directly onto the video frames during rendering. Unlike soft subtitles (which require an external SRT file or player toggle), burned-in captions display universally on any device, social media platform, or video player without relying on platform support.

When to Use Hardcoded Captions

• Social Media Short-Form (Reels, TikTok, Shorts): Mobile users frequently watch videos on mute. Burned-in captions ensure 100% viewer retention.
• Digital Signage & Kiosks: Displays running silent loops rely on visible text rendered on the frame.
• Universal Web Playback: Guarantees custom fonts and brand colors display identically across iOS, Android, Windows, and Mac.

Subtitle Formatting Best Practices

• Safe Zone Margins: Keep bottom captions elevated 10 to 12% above the lower frame boundary to prevent overlapping with platform UI elements (like TikTok sound titles or video progress bars).
• Contrast & Legibility: Always use a dark background pill box or thick text stroke when rendering captions over dynamic background footage.

FAQ

Q: Is my video uploaded to any server?
A: No. All video decoding, canvas drawing, subtitle rendering, and video recording take place 100% inside your local browser memory.

Q: What subtitle formats are supported?
A: Supports standard .SRT (SubRip) and .VTT (WebVTT) subtitle files, as well as direct text pasting.

When to burn captions in

Burned-in captions are part of the picture and cannot be switched off, translated or restyled. That permanence is the entire trade. It guarantees the words appear wherever the video goes, and it removes every choice the viewer would otherwise have.

Burn in when the platform cannot be trusted to render a caption track, which in practice means most social feeds. Video watched silently while scrolling needs text visible by default, and a caption file the platform ignores or renders illegibly delivers nothing. This is why social cuts are captioned differently from the same content on a long-form platform.

Use a separate caption track wherever it is supported. It lets viewers turn captions off, choose a language, and use their own size and contrast settings, which matters for people who need larger text than your design provides. A caption track is the accessible option, and burning in should be a deliberate exception rather than the default.

Style for the worst background in the video, not the average one. Burned-in text sits over whatever the picture does, so text passing over a dark shot becomes invisible over a bright one. A semi-transparent plate or a heavy outline guarantees legibility regardless, and both are less intrusive than they sound.

Keep the text clear of the lower edge. Platform interface elements, progress bars and automatic captions all occupy that region, and burned-in text placed there competes with them. Sitting slightly higher than feels natural during design keeps the words readable in the place they will actually be watched.

Vocabulary

Burned-in captions. Text rendered permanently into the video image, sometimes called open captions or hardcoded subtitles. Always visible on every platform, and impossible to disable, translate, resize or restyle once the file is exported.

Closed captions. Text supplied as a separate track the player renders, letting viewers switch them off, change language and adjust appearance. The accessible default wherever a platform supports them.

Caption plate. A solid or semi-transparent background drawn behind caption text so it sits on a known colour rather than directly on moving picture. The reliable way to keep burned-in text legible throughout.

Safe area. The region of the frame clear of platform interface and cropping. Burned-in captions placed outside it compete with progress bars and automatic captions, or get cut off entirely.