Apple ProRes is a high quality, "visually lossless" lossy video compression format developed by Apple Inc. for use in post-production that supports video resolution up to 8K. It is the successor of the Apple Intermediate Codec and was introduced in 2007 with Final Cut Studio 2. Much like the H.26x and MPEG standards, the ProRes family of codecs use compression algorithms based on the discrete cosine transform (DCT). ProRes is widely used as a final format delivery method for HD broadcast files in commercials, features, Blu-ray and streaming.
Overview
ProRes is a line of intermediate codecs, which means they are intended for use during video editing, and not for practical end-user viewing. This is achieved by only using intra-frame compression, where each frame is stored independently and can be decoded with no dependencies on other frames. The benefit of an intermediate codec is that it offers excellent random access performance in post-production applications, and retains higher quality than end-user codecs while still requiring much less expensive disk systems compared to uncompressed video. It is comparable to Avid's DNxHD codec or CineForm which offer similar bitrates and are also intended to be used as intermediate codecs. ProRes is a DCT scalar based intra-frame-only codec and is therefore simpler to decode than distribution-oriented formats like H.264. In 2018 Apple added a new "ProRes RAW" (compressed Bayer filter) to Final Cut Pro X, after Blackmagic Design implemented compressed Bayer as "CinemaDNG 3:1" and "CinemaDNG 4:1" in their cameras and DaVinci Resolve.
Data rates
ProRes supports different data rates and different resolutions. All ProRes422-variants use chroma subsampling of 4:2:2 at 10-bit color depth. ProRes 4444 and 4444 XQ samples color in the 4:4:4 schema with a color depth of 10 or 12 bits, and can optionally include an alpha channel.
ProRes 422
Key features
8K, 5K, 4K, UHD, 2K, HD (up to 1920×1080), & SD resolutions
4:2:2 chroma subsampling
up to 12-bit sample depth
I frame-only encoding
Variable bitrate (VBR) encoding
Normal 147 Mbit/s and High-Quality 220 Mbit/s and ProRes (LT) 100 Mbit/s as well as ProRes Proxy for HD 45 Mbit/s for HD resolution at 60i Normal 42 Mbit/s and High-Quality 63 Mbit/s for SD resolution at 29.97 Fast encoding and decoding (both at full size and half size)
ProRes 4444 and ProRes 4444 XQ
ProRes 4444 and ProRes 4444 XQ are lossy video compression formats developed by Apple Inc. for use in post-production and include support for an alpha channel.
ProRes 4444 was introduced with Final Cut Studio (2009) as another in the company's line of intermediate codecs for editing material but not for final delivery. It shares many features with other, 422, codecs of Apple's ProRes family but provides better quality than 422 HQ in color detail. It has a target data rate of approximately 330 Mbit/s for 4:4:4 sources at 1920x1080 and 29.97 fps
ProRes 4444 XQ was introduced with Final Cut Pro X version 10.1.2 in June 2014. It has a target data rate of approximately 500 Mbit/s for 4:4:4 sources at 1920x1080 and 29.97 fps, and requires OS X v10.8 (Mountain Lion) or later.
Key features
8K, 5K, 4K, 2K, HD (up to 1920×1080), & SD resolutions
4:4:4 chroma subsampling
Up to 12-bit sample depth for video
Variable bitrate (VBR) encoding
Alpha channel support at up to 16-bit sample depth
ProRes RAW
In April 2018 Apple released ProRes RAW. It is built upon the same technology as other ProRes codecs, but is directly applied to the raw data coming from the sensor, thus delaying the debayering process to the post-production stage. ProRes RAW therefore aims at quality and better color reproduction, rather than performance.
Playback
On 28 August 2008, Apple introduced a free ProRes QuickTime Decoder for both Mac and Windows that allows playback of ProRes files through QuickTime.
Open source projects
On 15 September 2011, FFmpeg introduced a free decoder for ProRes 422 for libavcodec.
FFmbc, a fork of FFmpeg customized for broadcast and professional usage, supports ProRes 422 and 4444 files.
On 1 October 2011, JCodec introduced an open source (FreeBSD License) pure Java decoder for ProRes 422, a translation of the FFmpeg version.
Encoding
Installing Final Cut Pro will install the ProRes codecs for encoding files on macOS. Without Final Cut Pro installed, QuickTime Player can also be used to capture ProRes 422 video from any compatible attached camera, using the "Maximum" quality setting when producing a Movie Recording.