Vimeo pixel aspect ratio 1:1: setsar in a video filter

Vimeo recommends a pixel aspect ratio of 1:1, or square pixels. On Sume you can send a filtergraph to POST /v1/video-filter containing setsar, which is on the server's allowlist alongside setdar and scale. Check the graph first with the free /v1/video-filter/check route.

Vimeo's guidance is from its compression guidelines. The Sume limits come from Video filter and the allowlist in packages/timeline-compiler/src/filter.ts, read 2026-10-01.

What does Vimeo say about pixel shape?

Under resolution, the page recommends compressing with a pixel aspect ratio of 1:1, then lists common sizes such as 1280 x 720 and 1920 x 1080. Square pixels mean the stored width and height already describe the picture shape, with no display stretch.

Which filters on the allowlist matter here?

How do I send it?

The filtergraph is filters-only, max 2048 characters and 32 named filters, with no inputs or stream specifiers. The server wraps it for you. The clip must already be a media.sume.com file and the source cap is 300 seconds. Replace /v1/video-filter/check with /v1/video-filter (and add an Idempotency-Key) to encode.

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/anamorphic.mp4",
    "filtergraph": "scale=1920:1080,setsar=1"
  }'

What will this not fix?

Scaling to a new width and height changes the picture's shape if the source ratio differs, so choose dimensions that keep the intended display shape. The docs do not describe how a clip's existing pixel aspect ratio is reported back, so check the result in a probe tool. Fields like vf, codec or crf are rejected; see ffmpeg fields rejected.