How to Export Video with an Alpha Channel

Last updated: · Written by the RenderAlpha team

Facts checked against the sources below on November 9, 2026. Commands run on FFmpeg 9.0.2.

A video keeps its transparency only when two things are true: the clip really has an alpha channel, and you export it in a format that can store one. An H.264 MP4 cannot. This guide covers both halves, with the checks we ran ourselves.

Short answer

Export with a codec that stores alpha: ProRes 4444 for editors, VP9 WebM for browsers, GIF for chats. Apple says only ProRes 4444 and 4444 XQ carry alpha among its ProRes codecs, and an H.264 MP4 has no alpha plane. Camera footage has no alpha yet, so remove the background first, then export.

Formats that keep an alpha channel

Only a few formats can store transparency. The last row matters most: the default H.264 MP4 export in most apps cannot, and our own test file confirms it. ffprobe reports pix_fmt=yuv420p for it, a pixel format with no alpha plane.

FormatKeeps alpha?Use it forSource
ProRes 4444 (.mov)Yes, alpha up to 16 bitsEditing and compositingApple ProRes support
VP9 WebMYes, but not rendered in SafariWebsites and OBSMDN
HEVC with alphaYesSafari and Apple appsWWDC19 session 506
GIFOn or off per pixel onlyChats and stickersMDN image types
H.264 MP4No (our test file: yuv420p)Finished clips on a solid backgroundOur ffprobe check

Step 1: make sure there is transparency to export

Footage from a camera or phone has no alpha channel. Before any export setting matters, the background has to be removed with a keyer on a flat green screen, with a mask you draw frame by frame, or with an AI background remover. Some editors include AI isolation, but it can sit in a paid tier: Blackmagic’s DaVinci Resolve Studio page lists magic mask for object isolation among its AI tools.

A black background in your editor preview is not transparency. Check the export over a colored layer, as in step 4.

Step 2: export from After Effects

Adobe’s documentation says After Effects creates a movie with an alpha channel if you choose RGB+Alpha, and that not all codecs support alpha channels. Pair that setting with a codec that does: ProRes 4444 in a QuickTime file. Our guide to exporting ProRes 4444 with alpha covers the details and the file sizes to expect.

Menu names for the alpha option change between Adobe versions, and Premiere’s export reference even lists a different option called Render Alpha Channel Only. So do not trust a remembered click path. Pick ProRes 4444, export, and verify the file as in step 4.

When you import a transparent file, After Effects may ask you to interpret the alpha as straight or premultiplied. Adobe notes that straight channels retain more accurate color information, while premultiplied ones work in a wider range of programs such as QuickTime Player.

Step 3: or remove the background and export online

For ordinary footage of a person, a pet or a product, RenderAlpha does both steps. Upload an MP4, MOV, WebM or GIF (up to 60 seconds per run), check the cutout on one frame for free, then export. Video costs 1 credit per second and there is no watermark.

Pick transparent WebM for websites and OBS, ProRes 4444 for editing apps (up to 10 seconds), or a transparent GIF for chats. It does not export HEVC with alpha. See specs and limits for every number, and WebM vs ProRes 4444 vs HEVC with alpha vs GIF to choose.

Step 4: check that the export really has alpha

Drop the file over a colored layer in your editor, or load it in Chrome or Firefox over a colored page. You can also read the metadata. For a ProRes 4444 file we made with ffmpeg, ffprobe reported profile=4444 and pix_fmt=yuva444p12le; the yuva prefix means an alpha plane is present. For a transparent WebM, see how to create one for the matching commands.

Run on FFmpeg 9.0.2. A ProRes 4444 file with alpha prints profile=4444 and a pix_fmt starting with yuva.
ffprobe -v error -select_streams v:0 -show_entries stream=codec_name,profile,pix_fmt -of compact clip.mov

If the result is black

Black in every app means the file never had alpha, for example an H.264 MP4. Grey or black only in Safari is a separate problem with VP9 WebM; see why transparent WebM turns grey or black in Safari.

Frequently asked questions

Can an MP4 have a transparent background?

An H.264 MP4 cannot. Our test MP4 reports pix_fmt=yuv420p, which has no alpha plane, so any transparency is replaced by a solid color when the file is written. Export WebM or ProRes 4444 instead.

Which ProRes flavors have an alpha channel?

Apple’s support page says ProRes 4444 and ProRes 4444 XQ are the only Apple ProRes codecs that support alpha channels.

What is the difference between straight and premultiplied alpha?

Adobe explains that straight channels store transparency only in the alpha channel, while premultiplied channels also bake it into the visible color channels, multiplied with a background color that is usually black or white.

Which format should I export for a website?

A VP9 WebM for most browsers, plus an HEVC-with-alpha file for Safari. Our Safari guide shows the two-file markup we tested.

Can I export transparent video from a live webcam?

No. RenderAlpha works on files you upload, not on a live camera feed.

Sources

Primary sources we checked. The date is when we last opened each page.