Add Subtitles
Burn SRT or VTT subtitles into your video. Processed locally in your browser.
Drop your file here
Related tools
Add subtitles to a video in your browser
Filzy lets you add subtitles to a video to burn subtitles directly into a video from an SRT or VTT file, ensuring captions are always visible regardless of player. The tool runs ffmpeg.wasm directly inside your browser tab, so your video file is decoded and re-encoded on your CPU without ever uploading to a server. The output is an MP4 with subtitles permanently rendered into the frames (hard subs), playable on any device. Filzy supports MP4, MOV, WebM (+ SRT/VTT) as input. The free tier processes 3 files without an account; signing up unlocks unlimited use, with no daily cap and no watermark.
Files stay on your device
Decoding, processing, and re-encoding all happen in a Web Worker via ffmpeg.wasm. The video bytes never reach a server, no temporary copy is stored anywhere.
Local CPU speed
WebAssembly delivers near-native performance on your CPU. A 5-minute clip typically processes in 1 to 3 minutes on a modern laptop, depending on the operation.
No upload, no daily cap
Skip the multi-minute upload that plagues server-based tools. The bottleneck moves to your CPU, where you have full control. No daily limit, no watermark.
How to add subtitles to a video with Filzy
- 1
Drop your video
Drag the file in, or click to select. Filzy accepts MP4, MOV, WebM (+ SRT/VTT) files. The practical size limit is your device memory; multi-gigabyte files work on most modern laptops.
- 2
Filzy add subtitles tos the video locally
ffmpeg.wasm decodes the video, applies the operation, and writes the result. Progress is shown frame by frame in the browser. The output is an MP4 with subtitles permanently rendered into the frames (hard subs), playable on any device.
- 3
Download the result
Save the file, or send it straight to another Filzy tool such as Compress, Trim, or Add watermark. Files chained between Filzy tools also stay local.