Amazon lists 3840x2160, but Sume output tops out at 2160: what to do

You cannot make a 3840x2160 Amazon Sponsored Brands video with Sume's Timeline or trim output, because both document a limit of 256 to 2160 on each side. Amazon's page lists three resolutions: 1280x720, 1920x1080 and 3840x2160. Two of the three are reachable, so render 1920x1080 and treat it as the production setting. Amazon's own page does not say the 4K option is better for delivery; it just lists it.

Which resolution fits which tool

The limits below are what each page states, nothing measured.

Steps

• Set the output to 1920x1080 in Timeline, which is a legal pair of even integers inside 256 to 2160.
• Use fit: "cover" if the source is 16:9, or blur if it is not.
• Run POST /v1/timeline-1.0/plan first. It is unbilled and returns billable_minutes and estimated_cost_usd_micros.
• Render, then read the result URL. A 30-second video bills as one output minute, which at $0.10 is ten cents per the docs.
• If a reviewer insists on 4K UHD, make that file in your own editor. Do not upscale and re-label.

An upscaled 1080p source does not gain detail by being placed in a bigger frame anyway. If you generate the picture on Sume, the video models have their own resolution tiers, listed in the video router doc, and those are separate from Timeline's output limit.

Why 1080p is a sound default here

The practical question is whether a 4K file is worth the effort for this placement. Amazon's page lists the option, but the page text I read gives no rule that favours it. The same page gives a minimum video bit rate of 1 Mbps and recommends 4 Mbps or higher, and a maximum file size of 500MB. A 3840x2160 file would use much more of that file budget than a 1920x1080 one, so the headroom shrinks as the length grows.

For a 20-second ad, the size difference is small. For a 45-second ad, check the downloaded file against 500MB regardless of the resolution you pick. Sume does not report the output file size in the docs I read, so read it from the file after the download.

If your source footage is 4K and you want to keep the detail, cut and filter it on your own tools. If your footage was generated at 1080p or 720p, a bigger canvas adds nothing. Match the resolution to the source and to what Sume can output.

What Sume does not do

Sume does not write a 3840-pixel-wide Timeline or trim output today, and I found no setting that raises the 2160 side limit. If that changes, the Timeline page will say so. Also confirm the 500MB file cap and the codec on your final file, because Sume does not report them.