Vimeo can hide black bars; Sume bakes the right frame into the file

Vimeo's 10 September 2026 update added a Page theme tab for your logo, fonts and colors, and says you can also hide black bars on non-16:9 videos, per Vimeo's product updates, read 2026-10-01. That changes how the page shows the video. It does not change the file. If a clip is going anywhere other than a Vimeo page, render the frame you want into the MP4 with Timeline 1.0.

Why do black bars appear at all?

Bars appear when a clip's aspect ratio differs from the box that plays it. A 9:16 clip in a 16:9 player gets bars on the sides, and the reverse gets bars above and below. Hiding the bars in the page is one fix. Matching the file to the destination is the other, and it works on every platform, not only the one with a theme setting.

Which Timeline setting decides what fills the frame?

How do I render a 16:9 version of a vertical clip?

Set output.width and output.height (even integers from 256 to 2160) to the target, then pick fit for the slot. The default output is 1080x1920, so a landscape target needs an explicit size. A timeline needs an audio spine: detach the clip's own audio first with Audio detach, then pass that file as audio.url. For a silent clip, use audio.mode: "silence" with a duration instead.

curl -X POST https://api.sume.com/v1/timeline-1.0/render \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: landscape-blur-001" \
  -d '{
    "audio": {
      "url": "https://media.sume.com/artifacts/artf_demo/talk.wav",
      "duration_seconds": 24
    },
    "output": { "width": 1920, "height": 1080 },
    "video": [
      { "source_url": "https://media.sume.com/artifacts/artf_demo/vertical.mp4",
        "start": 0, "duration": 24, "fit": "blur" }
    ]
  }'

What does it cost and what are the limits?

Timeline renders are metered at the rate card's price, which reads $0.10 per output minute. Audio is capped at 1,800 seconds and video[] at 200 slots. The /plan route compiles the document without billing, so use it to check the document before a real render.