Resolve 21.1 source viewer aspect ratio: check clips first

In DaVinci Resolve 21.1 the source viewer shows a clip at its original aspect ratio, whether the timeline is vertical or horizontal. If you also need to know that ratio before an edit, Sume's video inspect returns probe facts and stills whose entries carry width and height, and it is unbilled for probe and stills.

Resolve claims come from Blackmagic's 21.1 announcement; Sume claims from Video inspect and Video frames, both read 2026-10-01.

What changed in the Resolve 21.1 source viewer?

Blackmagic's announcement says the source viewer now preserves the source media's original aspect ratio independent of the timeline being vertical or horizontal, so customers working with both formats see their media correctly without manual adjustment.

That is a viewing change inside Resolve. It does not tell a script or an agent what shape a file is, which matters when you plan crops or reframes outside the editor.

How do I read a clip's shape with Sume?

Import the clip first (POST /v1/media-imports), then call POST /v1/video-inspect with its media.sume.com URL and an Idempotency-Key. The result carries probe and frames[{t,url,width,height}] as durable image artifacts.

Stills default to a max_edge of 768, so their width and height are the clamped size. When you want source size, pass the source edge in frames.max_edge (the docs allow up to 2160) or use POST /v1/video-frames, which omits the clamp.

curl -X POST https://api.sume.com/v1/video-inspect \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: aspect-check-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/talk.mp4",
    "frames": { "at": [0], "max_edge": 2160 }
  }'

Which Sume call fits which question?

Both routes are for one clip already in your workspace; neither re-encodes it.

Does inspect change my clip?

No. The docs say video inspect never re-encodes the source and never produces an MP4. If you then need a different shape, that is a separate step such as reframing after generation.

What should I do before conforming a batch?

Run inspect with frames: false on each clip, read the probe, and group clips by shape before you decide on crops. Use video-frames when you want one source-size still per clip for a visual check. Transcription is the only billed half of inspect, and it stays off unless you set transcribe: true; see extract video frames for the stills route.