Powered by WebAssembly
Pad Video Online (Free, No Upload)
Add padding or letterbox bars to any video right in your browser. Nothing gets uploaded to a server. Pad your video to fit a specific aspect ratio or resolution without cropping or stretching. Choose any background color for the padded area. 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 \"pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black\" {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
Pad to 9:16 portrait (white)
-i input.mp4 -vf "pad=ih*9/16:ih:(ow-iw)/2:0:white" output.mp4Pad to square (1:1)
-i input.mp4 -vf "pad=max(iw\,ih):max(iw\,ih):(ow-iw)/2:(oh-ih)/2:black" output.mp4Blurred background padding
-i input.mp4 -filter_complex "[0]scale=1080:1920:force_original_aspect_ratio=increase,crop=1080:1920,boxblur=20[bg];[0]scale=1080:1920:force_original_aspect_ratio=decrease[fg];[bg][fg]overlay=(W-w)/2:(H-h)/2" output.mp4Related Operations
Need to process at scale?
Automate this with the RenderIO FFmpeg API. Process thousands of files programmatically or through no-code video automation.