How to compress a video without losing its subtitles or captions

Whether compressing a video destroys your captions depends entirely on the caption type. Burned-in captions are part of the video image, so heavy compression can blur them just like any other fine detail — a separate SRT/VTT file isn't touched by video compression at all, since it's a different file entirely. You can compress your video free here and keep captions readable by getting the order right.

Burned-in vs. separate caption files

Burned-in captions are baked into the video's pixels — compressing the video compresses the captions right along with everything else. Small text is one of the first things to lose sharpness under heavy compression, since fine detail needs more bitrate to stay crisp than broad footage does.

Separate caption files (SRT/VTT) are untouched by video compression, full stop — it's a different file. The only thing to remember is re-attaching or re-uploading that caption file alongside the compressed video wherever you're publishing it, since compressing the video doesn't automatically carry the caption file along with it.

Why burned-in captions turn blurry

Fine text detail is exactly the kind of content that degrades first when a compressor is forced to hit an aggressive size target — the encoder has a limited bitrate budget and spends it where it judges detail matters most, which for typical footage isn't small overlaid text. If your target size is too aggressive for the caption font size you used, the text is usually the first casualty, well before the rest of the picture looks obviously bad.

The right order: captions first, compression last

Burn your captions into the video, then compress once, as the final step. Compressing before burning captions in and then compressing again afterward means two re-encoding passes instead of one — each one adds its own generation of quality loss, and it's entirely avoidable. One compression pass, done last, after captions are already part of the frame, both looks better and is faster.

What size target keeps captions legible?

There's no single universal number — it depends on resolution and how large your caption font is — but as a rough floor, staying above roughly 2-3 Mbps for 1080p video with burned-in text is a reasonable target if legibility matters. Below that, fine text detail is usually the first thing to visibly suffer, often before the rest of the frame looks obviously compressed.

Compressing for a specific size limit

If you're compressing for a platform with a hard size cap — Discord, email, MMS — see our post on shrinking a video for text or email while keeping captions readable for the specific numbers those limits actually are.

The bottom line

Soft caption files are immune to compression entirely — just remember to keep them attached. Burned-in captions survive compression fine as long as you burn them in first and compress once, last, rather than compressing twice. Try WavyVid's compress tool free — pick your target size, and if captions are already burned in, you're done in one pass.