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MP4 to VP9 WebM Converter (Free, Online, No Upload)

Convert any MP4 file to VP9-encoded WebM right in your browser. Nothing gets uploaded to a server. VP9 is Google's royalty-free video codec with compression quality close to H.265. The conversion runs locally using FFmpeg compiled for your browser, so your files stay 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}} -c:v libvpx-vp9 -crf 31 -b:v 0 -c:a libopus {{out_video}}",
  "input_files": {
    "in_video": "https://example.com/input.mp4"
  },
  "output_files": {
    "out_video": "output.webm"
  }
}'

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

Common Variations

High quality (CRF 20)
-i input.mp4 -c:v libvpx-vp9 -crf 20 -b:v 0 -c:a libopus output.webm
Target 2Mbps bitrate
-i input.mp4 -c:v libvpx-vp9 -b:v 2M -c:a libopus output.webm
Fast encoding
-i input.mp4 -c:v libvpx-vp9 -crf 33 -b:v 0 -cpu-used 4 -c:a libopus output.webm

Related Operations

Free VP9 to MP4 Converter Online | RenderIOFree MP4 to WebM Converter Online | RenderIOFree MP4 to AV1 Converter Online | RenderIOCompress Video Online Free, No Upload Required | 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