How to encode prores 4444 with alpha for vfx
- Step 1Confirm your source has alpha — ProRes 4444 only carries transparency if the input does. Your source should be a format that stores alpha — for example a PNG/WebP image sequence assembled to video, a VP9/
yuva420pWebM, or another 4444 render. An opaque MP4 has no alpha to preserve. - Step 2Open the ProRes encoder — Load the ProRes encoder. It is a Pro-media tool (
minTier: pro_media); 4444 renders are the largest ProRes output, so confirm your plan first. - Step 3Drop the source with alpha — Drag in the file. Recognised containers include MOV, MKV, and WebM (the common carriers of alpha video). One file per run; nothing uploads.
- Step 4Select the 4444 profile — Set Profile to
4444. This is the single setting that switches the pixel format toyuva444p10leand turns on the alpha plane. Leaving it on422/422hqwritesyuv422p10lewith no alpha — the transparency would be lost. - Step 5Choose the save location and encode — Because the tool streams, pick where the
…-prores.movsaves. FFmpeg.wasm runsprores_ksat profile 4 locally. 4444 is the heaviest profile, so expect the largest files and the longest encode of the three. - Step 6Verify the alpha in your compositor — Import into After Effects/Nuke/Fusion and check the alpha channel interprets correctly (straight vs premultiplied per your pipeline). If the alpha reads as black, the source likely had no real alpha — re-check step 1.
ProRes 4444 alpha encode — exact parameters
What this tool emits when you select 4444. The pixel format is the key difference from the 422 profiles — it includes an alpha plane.
| Parameter | Value for 4444 | Notes |
|---|---|---|
| Encoder | prores_ks | FFmpeg ProRes encoder via WebAssembly |
-profile:v | 4 | ProRes 4444 profile (the 4444 picker value) |
-pix_fmt | yuva444p10le | 10-bit 4:4:4 WITH alpha plane — the a in yuva is the alpha |
-vendor | apl0 | Apple vendor tag for genuine-ProRes recognition |
-c:a | pcm_s16le | Uncompressed 16-bit PCM audio |
| Container | .mov (video/quicktime) | QuickTime wrapper; carries the alpha channel |
Why 4444 and not the 422 profiles for alpha
Only the 4444 profile writes a pixel format with an alpha plane. The 422 profiles cannot carry transparency.
| Profile value | Pixel format | Alpha? | Chroma |
|---|---|---|---|
422 | yuv422p10le | No | 4:2:2 |
422hq | yuv422p10le | No | 4:2:2 |
4444 (this page) | yuva444p10le | Yes (alpha plane) | 4:4:4 |
Tier limits for 4444 renders
ProRes encoding requires Pro-media. 4444 is the heaviest profile, so the file-size cap matters most.
| Tier | Max file size | Files / batch | ProRes access |
|---|---|---|---|
| Free | 1 GB | 1 | No |
| Pro | 10 GB | 5 | No |
| Pro-media | 100 GB | 50 | Yes |
| Developer | 100 GB | Unlimited | Yes |
Cookbook
Real 4444+alpha encodes for the compositor/motion designer. The commands are the FFmpeg.wasm equivalents the 4444 picker drives.
Logo animation with transparency to a comp
A logo render with a transparent background must keep its alpha so it composites over live footage. Encode it as 4444 and the alpha rides along.
Input: logo-anim.mov (source carries alpha, e.g. yuva420p)
Profile: 4444
In-browser equivalent:
prores_ks -profile:v 4 -pix_fmt yuva444p10le \
-vendor apl0 -c:a pcm_s16le
Output: logo-anim-prores.mov (ProRes 4444, alpha intact)
→ After Effects shows the alpha channel; composites cleanly.Alpha WebM export to ProRes 4444
Browser/Lottie pipelines often produce VP9 WebM with alpha (yuva420p). Convert to ProRes 4444 so editors on macOS pipelines can use it.
Input: motion-graphic.webm (VP9, yuva420p — has alpha) Profile: 4444 Output: motion-graphic-prores.mov (ProRes 4444) Alpha plane carried into yuva444p10le.
Opaque clip encoded as 4444 = no transparency
A common mistake: picking 4444 on an opaque source. You get a valid 4444 file, but the alpha is fully opaque — there is nothing to composite.
Input: plate.mp4 (opaque H.264, no alpha) Profile: 4444 Output: plate-prores.mov (ProRes 4444, alpha = fully opaque) → 4444 cannot invent transparency; the source had none.
Image sequence assembled, then 4444 encode
PNG/EXR-style transparency usually starts as an image sequence. Assemble it to an alpha-carrying video first, then encode the master as 4444.
Step 1 (your renderer/NLE): PNG sequence with alpha → alpha video Step 2 — prores-encoder, Profile 4444: alpha-video.mov → alpha-video-prores.mov Result: a single ProRes 4444 deliverable with the alpha plane.
Pick 422 HQ instead when you don't need alpha
4444 is the heaviest profile. If the shot is opaque, encode 422 HQ for a much smaller master at the same delivery quality for 4:2:2 material.
Opaque plate, master delivery: Profile 4444 → -profile:v 4 (huge, alpha you won't use) Profile 422hq → -profile:v 3 (smaller, 4:2:2 broadcast master) Reserve 4444 for genuine transparency.
Edge cases and what actually happens
Source has no alpha — 4444 output is opaque
No alpha to addProRes 4444 carries an alpha channel but cannot create one. Encoding an opaque MP4 as 4444 produces a valid file whose alpha is fully opaque — there is nothing to composite. Your source must already store transparency (alpha image sequence, yuva420p WebM, another 4444 render).
Picked 422 or 422 HQ for an alpha source
Alpha lostThe 422 and 422 HQ profiles write yuv422p10le, which has no alpha plane — selecting them on a transparent source silently discards the alpha. Only the 4444 profile (yuva444p10le) preserves transparency. Always pick 4444 when alpha matters.
4444 files are the largest of all profiles
Expected4444 adds a fourth (alpha) plane and uses 4:4:4 chroma, so it is heavier than 422 HQ, which is itself heavier than 422 — and all are far bigger than the source. Reserve 4444 for shots that truly need alpha or 4:4:4; use 422 HQ for opaque masters.
Alpha reads as straight vs premultiplied incorrectly
Interpret in compositorProRes 4444 stores the alpha plane; how your compositor interprets it (straight vs premultiplied) is an import setting on the receiving end, not something this encoder changes. If edges fringe or look haloed, switch the alpha interpretation in After Effects/Nuke for that footage item.
Not available on Free or basic Pro
403 tier-gatedProRes encoding requires the Pro-media tier (minTier: pro_media). VFX/graphics work generally lives on Pro-media or Developer, which also grant the 100 GB file limit that heavy 4444 renders need.
Source over the tier size limit
413 too largeA source above your tier's video cap (Pro-media/Developer 100 GB) is rejected before encoding. Because 4444 output is so large, watch the source size too — split long renders with the video splitter and encode in parts.
Chroma looks softer than expected from a 4:2:2 source
Limited by source4444 stores 4:4:4 but cannot reconstruct chroma a 4:2:0/4:2:2 source never had. You get a 4:4:4 container, not recovered colour detail. For genuine 4:4:4 benefit, the source should already be 4:4:4 (e.g. graphics renders, RAW debayers).
Need the alpha as a separate matte file
Not supported hereThis tool outputs a single ProRes 4444 MOV with an embedded alpha plane, not a separate fill+matte pair. If your pipeline requires a separate matte, generate it in your compositor; this encoder embeds the alpha rather than splitting it.
Image-only or audio-only file dropped in
Invalid inputThe encoder needs a single video container. A still image or audio file fails. Assemble image sequences to a video first; this tool encodes video, not stills.
Frequently asked questions
Does this actually preserve my alpha channel?
Yes — when you select the 4444 profile. That writes yuva444p10le (the a is the alpha plane) via prores_ks at -profile:v 4. The 422 and 422 HQ profiles use yuv422p10le, which has no alpha, so they would drop transparency. Pick 4444 for any shot with an alpha channel.
Why is my 4444 output fully opaque?
Because the source had no alpha. ProRes 4444 carries transparency but cannot invent it — encoding an opaque MP4 as 4444 gives you an opaque 4444 file. Your input must already store alpha: an alpha image sequence, a yuva420p WebM, or another 4444 render.
Will After Effects / Nuke / Fusion read the alpha?
Yes. The file is genuine Apple ProRes 4444 (prores_ks, profile 4, vendor apl0) in a QuickTime MOV with the alpha plane embedded. Those compositors interpret the alpha on import; set straight vs premultiplied per your pipeline if edges fringe.
What's the difference between 4444 and 422 HQ?
422 HQ is 10-bit 4:2:2 with no alpha (yuv422p10le, profile 3). 4444 is 10-bit 4:4:4 WITH an alpha plane (yuva444p10le, profile 4). Use 4444 for transparency or full chroma; use 422 HQ for opaque masters where it would be much smaller.
What source formats carry alpha I can feed in?
Commonly a QuickTime MOV that already holds alpha, a VP9 WebM in yuva420p, or a video assembled from an alpha image sequence. The recognised input containers are MP4, MOV, MKV, WebM, AVI, M4V, and TS, but only ones whose video stream actually stores alpha will yield a useful 4444 alpha.
Why are 4444 files so big?
4444 adds an alpha plane and uses 4:4:4 chroma, so it is the heaviest ProRes profile — larger than 422 HQ, and far larger than the source. That is expected; reserve it for shots that genuinely need alpha or full chroma.
Can I export a separate fill and matte?
No. This tool writes a single ProRes 4444 MOV with the alpha embedded, not a separate matte file. Generate a separate matte in your compositor if your pipeline requires fill+key as two files.
Does my footage upload?
No. The encode runs in FFmpeg.wasm in your browser, so unreleased shots, logos, and client graphics never leave your machine. That is the point for VFX work under NDA.
Can I control how the alpha is premultiplied?
Not in this tool. The encoder embeds the alpha plane as it is in the source; straight vs premultiplied interpretation is an import setting in your compositor. The only control here is the profile picker.
Do I need a Mac to render ProRes 4444?
No. It runs in the browser via WebAssembly, so you can produce ProRes 4444 with alpha on Windows, Linux, or a Chromebook. See the no-Mac ProRes guide.
Will 4444 sharpen a 4:2:0 source?
No. It stores 4:4:4 but cannot reconstruct chroma the source never recorded. For a real 4:4:4 benefit the source should already be 4:4:4, such as graphics renders or RAW debayers.
What tier do I need for 4444?
Pro-media or higher (minTier: pro_media). Free and basic Pro cannot run the ProRes encoder. Pro-media also unlocks the 100 GB per-file limit that heavy 4444 renders typically require.
Privacy first
Every JAD Video tool runs entirely in your browser via WebCodecs and FFmpeg (WebAssembly). Your video files never leave your device — verified by zero outbound network requests during processing.