The master format
ProRes delivery.
Masters without a re-encode.
ProRes is the file your client actually needs and the one no browser can play. The official data rates, what a minute weighs, and a handoff that never re-encodes the master.
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By uncompressed.io · Updated September 2026
What is ProRes
Built for the timeline.
Adopted for the handoff.
Post production standardized on ProRes for two dull, excellent reasons: every frame stands alone, and every flavor has a published data rate you can plan storage around.
ProRes is Apple’s family of intermediate codecs, and the word intermediate is doing real work. It is intra-frame: each frame is compressed on its own, like a strip of stills, so an editor can scrub, cut, and play backwards without the machine reconstructing anything. Delivery codecs work the other way. In H.264 or HEVC, most frames are stored as changes applied to a neighbor, which is why they stream cheaply and edit badly.
The second habit that made it the handoff standard is predictability. Apple publishes a target data rate for every flavor at every frame size, and the encoder holds it: a frame peaks about 10 percent above target, so a producer can size drives before the export exists. Apple rates 422 HQ, the default finishing flavor, as “visually lossless through many generations of decoding and reencoding.”
That reliability is priced in bits. The table below is Apple’s own numbers with the arithmetic done: what one minute of each flavor weighs.
Data rates
What a master weighs.
Official target rates by flavor. ProRes delivery is a logistics problem before it is a hosting problem, and these numbers are the logistics.
Target rates from About Apple ProRes and the Apple ProRes White Paper (April 2022), read September 2026. UHD is 3840x2160. GB per minute computed from the UHD 30 fps column: rate x 60 seconds / 8 bits per byte. ProRes is variable bitrate; frames peak about 10 percent above target.
884 Mbps
UHD 30p 422 HQ target
Apple White Paper target rate at 3840x2160
6.6 GB
One minute of UHD 422 HQ
884 Mbps x 60 s / 8. A ten-minute cut is about 66 GB.
+10%
VBR peak over target
Per-frame maximum, per the ProRes White Paper
The browser problem
No browser plays ProRes.
Ours included.
Not Chrome, not Safari, not Firefox, and not this site’s player either. The decoder lives on the viewer’s machine, and no browser ships one for ProRes.
uncompressed.io streams the exact bytes you upload with no re-encode, but the decode still happens on the client side, and in a browser that means H.264, HEVC, or AV1 in MP4 or MOV. A ProRes file handed to a web page has nothing on the other end that can turn it into pictures. Any service promising ProRes playback in a browser tab is playing you a transcode.
The macOS app supports R3D, BRAW, N-RAW and ProRes on compatible Macs. Playback depends on the codec, hardware, storage and file availability; test a short clip on the recipient’s Mac. For browser review, use a supported H.264, HEVC or AV1 export.
Browser playback depends on codec and profile support, hardware and the connection. There is no universal bitrate that guarantees smooth playback. Use a short H.264 or HEVC export to test the recipient’s setup before sharing an important film.
Camera-file playback is hardware-dependent. Local decoding capacity should not be compared with a hosted web rendition as a measure of picture quality.
The workflow
The delivery.
One link, both files.
One link carries the whole handoff: the master as a download, an HEVC twin for the browser, and the approval that says which version is final.
Upload the master
The ProRes goes up as-is: resumable, survives navigation, up to 5 TB per file. Nothing re-encodes it on arrival, so the bytes that come back out are the bytes you exported.
Attach the web twin
Export an HEVC 10-bit version beside the master and upload it to the same room. Browsers play it untouched, and new versions keep the same link, so revisions never scatter across URLs.
Client reviews anywhere
A browser plays the HEVC twin; the macOS app plays the master itself. Timecoded comments, drawings on the frame, and red or green approvals land per version, no client account needed.
Switch on the originals
When the approval goes green, flip original-file downloads on. The client pulls the exact master from the link where they signed off, and the download is the file, not an approximation of it.
The room at /review holds the exchange end to end: the share link is the auth, so a client opens it with no account, and sign-off attaches to a specific version of a specific file rather than a sentence in an email thread. Notes come back to the timeline through free NLE sync: a DaVinci Resolve script, a signed Premiere panel, and a one-drag Final Cut bundle with markers and drawing stills already placed.
Judgment calls
Flavor, then vehicle.
Two decisions close every ProRes delivery: which flavor to master, and whether this particular file should go over the wire at all.
422 HQ or 4444
When a drive is still the right call
Terabytes, not gigabytes
A season of masters, or camera negatives beside the finish, can outrun what either side's connection moves in a useful window. Our per-file limit is 5 TB; a courier van does not have one.
The contract names the medium
Broadcast and studio delivery specs often name LTO or a specific drive format with a physical chain of custody. Meet the spec as written.
The recipient is offline by policy
Air-gapped facilities and some security-conscious studios do not accept internet delivery at all. No workflow argument beats their policy.
The pipe cannot carry it
A slow office connection makes a 300 GB handoff a drive job no matter what the software can do. Bandwidth is a hard constraint; plan around it.
Even then, the hybrid usually wins: the drive carries the archive while the link carries the approval, so the client has watched and signed off before the courier is booked, and a re-export does not mean a second shipment. For the rest of the handoff, formats beyond ProRes included, see the guide to delivering final video files to clients.
Test native playback and browser delivery separately
A supported native playback path does not make every ProRes file universally playable in a browser. Choose a representative master and test the actual recipient’s workflow. If you supply a compatible review export, label it separately from the master.
When the client will work offline, finish preparing the required media before disconnecting. Verify playback near the end as well as the beginning. Keep the delivery copy and your independent backup separate from the app’s working cache.
Questions
Frequently asked
Can you play ProRes in a browser?
No. Browsers decode H.264, HEVC, and AV1, and none of them ships a ProRes decoder, so a ProRes file cannot play in any browser tab on any host, ours included. The uncompressed.io macOS app plays ProRes natively up to 8K 4:2:2 HQ at 60 fps; for browser review you attach an HEVC export beside the master.
How big is a ProRes file per minute?
At UHD 3840x2160 and 30 fps, Apple's target rates work out to about 4.4 GB per minute for ProRes 422, 6.6 GB for 422 HQ, and 9.9 GB for 4444. At 1080p 29.97 fps, 422 HQ targets about 220 Mbps, or roughly 1.65 GB per minute. ProRes is variable bitrate, with frames peaking about 10 percent above target.
Should I deliver ProRes 422 HQ or 4444?
422 HQ is the standard finishing master for broadcast and online work. Choose 4444 when the file needs an alpha channel or will be composited or re-graded downstream; the 4:4:4 chroma matters there and costs half again the bits, 1,326 Mbps against 884 at UHD 30p. The delivery workflow is the same either way, only the size changes.
How do I send a ProRes file to a client without a hard drive?
Host the master somewhere that will not re-encode it and let the client download it from the same link where they reviewed the cut. On uncompressed.io, uploads take masters up to 5 TB per file, resumable, and the owner switches on original-file downloads for the final pull. Longer masters split per reel or go on a drive; the table on this page tells you which side of 5 TB you are on.
What should the web review version be if ProRes will not play?
Browser playback depends on codec and profile support, hardware and the connection. There is no universal bitrate that guarantees smooth playback. Use a short H.264 or HEVC export to test the recipient’s setup before sharing an important film.
Let your client see the film you exported
Upload a short browser-compatible export and share it with one client. Check the picture, collect feedback and choose a paid plan when you need room for more films.
Sources
- 1.About Apple ProRes (Apple Support) (1080p target data rates and the 422 HQ visually lossless rating)
- 2.Apple ProRes White Paper, April 2022 (PDF) (target data rate tables at UHD and 8K; variable bitrate behavior)
- 3.Guidelines for determining playback resolution (Vimeo Help Center) (4K H.264 maximum 22 Mbps)
- 4.What are my assets converted to when uploaded (Frame.io Support) (uploads served as H.264/H.265 MP4 proxies)
- 5.Web video codec guide (MDN Web Docs) (inter-frame prediction in delivery codecs)