How to Export ProRes 4444 with Alpha

Last updated: · Written by the RenderAlpha team

Facts checked against the sources below on November 9, 2026. Commands and file sizes measured on FFmpeg 9.0.2 with a 5 second 1280×720 test clip.

ProRes 4444 is the editing format that carries a real alpha channel. If you want to drop a cut-out person or object onto a timeline, this is the file to ask for. This guide covers what Apple documents, the file sizes we measured, and three ways to make one.

Short answer

Only Apple ProRes 4444 and 4444 XQ carry alpha, according to Apple’s support page; ProRes 422 and its variants do not. In After Effects choose a QuickTime ProRes 4444 export with RGB+Alpha. Expect big files: our 5 second 720p test clip came to 96 MB as ProRes 4444, against 1.0 MB as a WebM.

What Apple says about ProRes and alpha

These facts come from Apple’s “About Apple ProRes” support page, which we opened on November 9, 2026. The data rates are for 1920×1080 at 29.97 fps, so a clip at that size will be larger than our 720p test.

TopicWhat the page says
Which flavors have alphaProRes 4444 and 4444 XQ are “the only Apple ProRes codecs that support alpha channels”.
Alpha qualityProRes 4444 has a mathematically lossless alpha channel of up to 16 bits.
Color depthProRes 4444 supports up to 12 bits per image channel.
Target data rateAbout 330 Mbps for ProRes 4444 and about 500 Mbps for 4444 XQ, for 4:4:4 sources at 1080p and 29.97 fps.

How big are the files?

We encoded a 5 second 1280×720, 24 fps clip with ffmpeg’s prores_ks encoder. The ProRes 4444 file was 96 MB, about 160 Mbps by ffprobe, and ffprobe reported pix_fmt=yuva444p12le. The same clip as a transparent VP9 WebM at CRF 30 was 1.0 MB. Use ProRes as the file you edit with and a transparent WebM for the web; the format comparison puts the numbers side by side.

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. So set the output to a QuickTime file with the ProRes 4444 codec and choose RGB+Alpha. Adobe changes menu wording between versions, so confirm with the check below instead of trusting a remembered click path.

Other editors follow the same rule: the codec has to be ProRes 4444 or 4444 XQ, and the app needs an option to include alpha. Premiere Pro’s export reference lists a separate option called Render Alpha Channel Only, which is not the same thing. We have not verified the exact menu steps in Premiere Pro, Final Cut Pro or DaVinci Resolve, so we do not give click paths for them.

When you bring a transparent file into After Effects, you may need to interpret the alpha. Adobe says straight channels retain more accurate color information, and premultiplied channels are compatible with more programs, such as QuickTime Player. A player that shows a colored or dark edge may be using a different alpha interpretation than your editor.

Make one with ffmpeg

If you have a transparent WebM, ffmpeg can write ProRes 4444 with alpha. We ran this on FFmpeg 9.0.2; ffprobe on the result reported codec_name=prores, profile=4444 and pix_fmt=yuva444p12le. Put -c:v libvpx-vp9 before the input so the WebM’s alpha is read. See converting MOV and WebM files for the reverse direction.

Transparent WebM to ProRes 4444 with alpha.
ffmpeg -c:v libvpx-vp9 -i input.webm -c:v prores_ks -profile:v 4444 -pix_fmt yuva444p10le output.mov

Or remove the background and download ProRes 4444

For footage with a real background, upload it to RenderAlpha, check the cutout on one frame for free, and export ProRes 4444. ProRes export is limited to 10 seconds; for longer clips export a transparent WebM, up to 60 seconds per run. It does not export HEVC with alpha. See specs and limits for every number.

Check that the alpha channel is there

Place the file over a colored layer in your editor. You can also read it with ffprobe: a ProRes 4444 file with alpha prints profile=4444 and a pix_fmt that starts with yuva.

Run on FFmpeg 9.0.2.
ffprobe -v error -select_streams v:0 -show_entries stream=codec_name,profile,pix_fmt -of compact output.mov

Frequently asked questions

Does ProRes 422 have an alpha channel?

No. Apple’s support page says ProRes 4444 and 4444 XQ are the only Apple ProRes codecs that support alpha channels.

Why is my ProRes file so large?

ProRes trades size for editing quality. Apple’s page gives a target of about 330 Mbps for ProRes 4444 at 1080p and 29.97 fps. Our 720p 24 fps test file was 96 MB for 5 seconds.

Why does my transparent video look black or green in a player?

Some players ignore alpha or use a different alpha interpretation than your editor. Check the file over a colored layer in an editor. See why transparent video looks black for the likely causes.

Can I export ProRes 4444 from an MP4?

You can wrap any video in ProRes, but an H.264 MP4 has no alpha to keep. Our test MP4 reports pix_fmt=yuv420p. Remove the background first.

Does RenderAlpha limit ProRes length?

Yes, ProRes 4444 export is limited to 10 seconds. A transparent WebM can run up to 60 seconds per run.

Sources

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