Spotify video podcast aspect ratio: any, but shown in 16:9

Spotify for Creators accepts any aspect ratio for a video episode, but its video specs say some Spotify apps display the video with letterboxing or pillarboxing to fill a 16:9 space. If you want the frame to be 16:9 itself, produce a 16:9 file before you upload.

Spotify's side is from its Video specs page; Sume's side from Video trim and Timeline 1.0, all read 2026-10-01.

What does Spotify do with a vertical or square file?

The specs page lists the aspect ratio as "Any aspect ratio", with the caveat above. So a 9:16 file is not rejected; it is shown inside a 16:9 area with bars on the sides. Whether those bars matter depends on the look you want, so check one episode in the app first.

How do I get a true 16:9 file with video trim?

POST /v1/video-trim takes an optional output of { width, height, fps } that conforms the cut on the way out. Width and height are 256 to 2160, and output works only with precision: "exact" (the default); with keyframe it is refused as video_trim_output_requires_exact. The docs list no fit mode for this field, so use it when your source is already near 16:9 and you only need the size set; check the result frame before publishing.

curl -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: episode-169-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/episode.mp4",
    "start": 0,
    "duration": 600,
    "output": { "width": 1920, "height": 1080 }
  }'

When should I use Timeline instead?

Timeline 1.0 has a per-clip fit: cover (default), contain, stretch or blur. Its default output is 1080 by 1920, so for a landscape episode set output.width and output.height to even integers in the 256 to 2160 range. contain keeps the whole picture and blur is the choice when you want the bars filled rather than left empty. See fit modes.

Which option fits which source?

Do I need to import the file first?

Yes. Video trim takes only a media.sume.com clip; there is no open-internet fetch, so import with POST /v1/media-imports first. For a similar reframing problem see convert 4:3 video to 16:9.