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Poof returns a video with a real alpha channel, so the subject can sit on top of any page, scene or timeline without keying. There are three transparent formats: All three need channels=rgba, which is the default. MP4 cannot carry alpha; for a solid background use the green screen guide instead. The request and job flow are the same as in Video background removal; only format changes.

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WebM for the web

Poll the job and download result_url. Host the file yourself (the CDN link expires after 24 hours), then play it like any video. muted and playsinline let it autoplay on mobile:
Pass size=medium (1280 px on the longest side) or size=preview (640 px) when the video plays small on the page; the file gets much lighter and the credits are the same.

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Safari

Safari does not show the alpha channel of a VP9 WebM, so the background turns opaque there. Safari plays HEVC with alpha instead. To cover every browser, request a mov (ProRes 4444) as well, convert it to HEVC with alpha on a Mac, and list it first:
Safari picks the HEVC file; Chrome, Edge and Firefox skip the QuickTime source and play the WebM. Test on the browsers you target. The ProRes file itself is too large to serve on the web.

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ProRes 4444 for video editors

The result is a QuickTime file with ProRes 4444 and a 10-bit alpha channel. Drop it on a track above your background and it composites straight away, with no keying and no green spill. ProRes is an editing codec, so expect files many times larger than the source; export the final edit to your delivery format as usual. With the SDKs:

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Transparent GIF

format=gif returns a looping GIF with a transparent background. It plays wherever an image does, including chat apps, email and Safari, with no <video> tag:
GIF is an old format, so the output has limits the other formats do not:
  • 1-bit transparency. Each pixel is either fully opaque or fully transparent (alpha of 50% or more is kept), so soft edges such as hair and motion blur are hard-cut. Use WebM or ProRes when the edges matter.
  • Up to 720p. GIF output is capped at 1280 px on the longest side whatever size says, because GIF has no inter-frame compression and files grow fast. size=preview (640 px) keeps a sticker small.
  • Up to 50 fps, looping forever, with no audio track.
A GIF is billed like any other video: 5 credits per second of source video (10 above 30 fps). Animated GIFs work as input too, so you can send a GIF and get a transparent GIF, WebM or MOV back.

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Only the matte

If your pipeline does its own compositing, channels=alpha returns the matte as a grayscale video (white subject, black background, no audio). format=mp4 gives the smallest file that every tool can decode. See Alpha matte video.

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Without code

In Studio at dash.poof.bg, upload a clip, choose WebM, MOV or GIF and download the result. Through the MCP server, ask your assistant for “a transparent WebM” or “a ProRes 4444 MOV” of a video URL.