Turn a video into a line-art sketch by API with edgedetect

A pencil-sketch look can be had with two allowlisted filters in Video filter: edgedetect to draw edges and negate to flip them to dark lines on white. The default wires mode draws white or gray wires on black, which is why the negate helps. This is a stylised effect for B-roll or title backgrounds, not a way to get a clean vector outline.

Which edgedetect options shape the lines?

How do I get dark lines on white?

Chain negate after edgedetect. In a local ffmpeg 9.0.1 run on a test pattern, mode=canny:low=0.1:high=0.3 followed by negate came out predominantly light. Raise high if the frame is a mess of lines and lower it if the lines break up.

curl -X POST https://api.sume.com/v1/video-filter/check \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/street.mp4",
    "filtergraph": "edgedetect=mode=canny:low=0.1:high=0.3,negate"
  }'

Does this make a cartoon of my footage?

No. It outlines edges and discards color and shading, so the result reads as a line drawing. If you want a painted or illustrated restyle of a clip, that is a generative job, not a pixel filter. This one is deterministic: the same clip and settings give the same result.

Is there a way to keep some color under the lines?

colormix mode mixes colors into the output, and the allowlist also has blend, so a graph can split the clip, edge-detect one copy and blend it over the original. Try a simple split and blend graph on a short clip first; the check will tell you whether the filters are allowed before you pay for an encode.

What does a filter job cost and where are the limits?

The docs list $0.02 per encode job, with a source of at most 300 seconds, a filtergraph of at most 2048 characters and 32 named filters. The /v1/video-filter/check route runs the same allowlist and source checks for free and returns valid and next_action; a graph that passes can still fail on the worker (bad expression, memory, time), which comes back as a structured job error.