Add Subtitles to Video (Free, Online, No Upload)

Burn subtitles directly into any video right in your browser. Nothing gets uploaded to a server. Load your SRT or ASS subtitle file and hard-code the text onto the video so it displays on any player without external subtitle support. The processing runs locally on your device.

Try it in your browser

Loading FFmpeg engine... (~31 MB)

Use the API

curl -X POST https://renderio.dev/api/v1/run-ffmpeg-command \
  -H "X-API-KEY: ffsk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
  "ffmpeg_command": "-i {in_video} -vf subtitles={in_video} {out_video}",
  "input_files": {
    "in_video": "https://example.com/input.mp4"
  },
  "output_files": {
    "out_video": "output.mp4"
  }
}'

Need an API key? Get your free API key to start processing files programmatically.

Common Variations

Custom font and size

-i input.mp4 -vf "subtitles=subs.srt:force_style='FontSize=28,FontName=Arial'" output.mp4

ASS subtitle file

-i input.mp4 -vf ass=subs.ass output.mp4

Soft subtitles (selectable)

-i input.mp4 -i subs.srt -c copy -c:s mov_text output.mp4

With background box

-i input.mp4 -vf "subtitles=subs.srt:force_style='FontSize=24,BorderStyle=4,BackColour=&H80000000'" output.mp4

Related Operations

Add Watermark to Video Online Free, No Upload | RenderIO Overlay Video Online Free, No Upload | RenderIO Resize Video Online Free, No Upload | RenderIO Free MKV to MP4 Converter Online | RenderIO

Need to process at scale?

Automate this with the RenderIO FFmpeg API. Process thousands of files programmatically or through no-code video automation.

Get your API key