Apple ProRes

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Apple ProRes is a lossy video compression format developed by Apple Inc. for use in post production that supports up to a 5K resolution. It is the successor of the Apple Intermediate Codec and was introduced in 2007 with Final Cut Studio 2.[1]

Apple ProRes is a line of intermediate codecs, which means they are intended for use during video editing, and not for practical end-user viewing. The benefit of an intermediate codec is that it 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 which are also intended to be used as intermediate codecs.

Introduction[edit]

Apple ProRes is one of the most popular codecs in professional post-production. The Apple ProRes family of video codecs has made it both possible and affordable to edit full-frame, 10-bit, 4:2:2 and 4:4:4:4 high-definition (HD), 2K, 4K, and 5K video sources with multistream performance in Final Cut Pro X.[2]

Apple ProRes Family Overview[edit]

Apple ProRes codecs provide an unparalleled combination of multistream, real-time editing performance, impressive image quality, and reduced storage rates. Apple ProRes codecs take full advantage of multicore processing and feature fast, reduced-resolution decoding modes. All Apple ProRes codecs support any frame size (including SD, HD, 2K, 4K, and 5K) at full resolution. The data rates vary based on codec type, image content, frame size, and frame rate. As a variable bit rate (VBR) codec technology, Apple ProRes uses fewer bits on simple frames that would not benefit from encoding at a higher data rate. All Apple ProRes codecs are frame-independent (or “intra-frame”) codecs, meaning that each frame is encoded and decoded independently of any other frame. This technique provides the greatest editing performance and flexibility.[3]

Apple ProRes Formats[edit]

Apple ProRes 4444 XQ[edit]

The highest-quality version of Apple ProRes for 4:4:4:4 image sources (including alpha channels), with a very high data rate to preserve the detail in high-dynamic-range imagery generated by today’s highest-quality digital image sensors. Apple ProRes 4444 XQ preserves dynamic ranges several times greater than the dynamic range of Rec. 709 imagery—even against the rigors of extreme visual effects processing, in which tone-scale blacks or highlights are stretched significantly. Like standard Apple ProRes 4444, this codec supports up to 12 bits per image channel and up to 16 bits for the alpha channel. Apple ProRes 4444 XQ features a target data rate of approximately 500 Mbps for 4:4:4 sources at 1920 x 1080 and 29.97 fps.[4]

Note: Apple ProRes 4444 XQ requires OS X v10.8 (Mountain Lion) or later.

Apple ProRes 4444[edit]

An extremely high-quality version of Apple ProRes for 4:4:4:4 image sources (including alpha channels). This codec features full-resolution, masteringquality 4:4:4:4 RGBA color and visual fidelity that is perceptually indistinguishable from the original material. Apple ProRes 4444 is a high-quality solution for storing and exchanging motion graphics and composites, with excellent multigeneration performance and a mathematically lossless alpha channel up to 16 bits. This codec features a remarkably low data rate compared to uncompressed 4:4:4 HD, with a target data rate of approximately 330 Mbps for 4:4:4 sources at 1920 x 1080 and 29.97 fps. It also offers direct encoding of, and decoding to, both RGB and Y’CBCR pixel formats.[5]

Apple ProRes 422 HQ[edit]

A higher-data-rate version of Apple ProRes 422 that preserves visual quality at the same high level as Apple ProRes 4444, but for 4:2:2 image sources. With widespread adoption across the video post-production industry, Apple ProRes 422 HQ offers visually lossless preservation of the highest-quality professional HD video that a single-link HD-SDI signal can carry. This codec supports full-width, 4:2:2 video sources at 10-bit pixel depths, while remaining visually lossless through many generations of decoding and reencoding. The target data rate of Apple ProRes 422 HQ is approximately 220 Mbps at 1920 x 1080 and 29.97 fps.[6]

Apple ProRes 422[edit]

A high-quality compressed codec offering nearly all the benefits of Apple ProRes 422 HQ, but at 66 percent of the data rate for even better multistream, real-time editing performance. The target data rate of Apple ProRes 422 is approximately 147 Mbps at 1920 x 1080 and 29.97 fps.[7]

Apple ProRes 422 LT[edit]

A more highly compressed codec than Apple ProRes 422, with roughly 70 percent of the data rate and 30 percent smaller file sizes. This codec is perfect for environments where storage capacity and data rate are at a premium. The target data rate of Apple ProRes 422 LT is approximately 102 Mbps at 1920 x 1080 and 29.97 fps.[8]

Apple ProRes 422 Proxy[edit]

An even more highly compressed codec than Apple ProRes 422 LT, intended for use in offline workflows that require low data rates but full‑resolution video. The target data rate of Apple ProRes 422 Proxy is approximately 45 Mbps at 1920 x 1080 and 29.97 fps.[9]

Note: Apple ProRes 4444 XQ and Apple ProRes 4444 are ideal for the exchange of motion graphics media because they are virtually lossless, and are the only Apple ProRes codecs that support alpha channels.

Playback[edit]

On 28 August 2008, Apple introduced a free ProRes QuickTime Decoder for both Mac and Windows that allows playback of Apple ProRes files through QuickTime.

Open source projects[edit]

On 15 September 2011, FFmpeg introduced a free decoder for Apple ProRes 422 for libavcodec.

FFmbc, a fork of FFmpeg customized for broadcast and professional usage, supports Apple ProRes 422 and Apple ProRes 4444 files. [1]

Encoding[edit]

Final Cut Pro version 10.1.2 fully supports ProRes 4444 XQ for editing, compositing, rendering, and exporting.[10]

Apple released Apple ProRes bundled with other pro codecs as a download for users with "qualifying copies of Final Cut Pro, Motion, or Compressor" installed, for OS X with QuickTime 7.6 and newer.[11]

At the April 2010 NAB Show, Digital Video Systems launched the first Windows 7 platform with the ability to encode to all the varieties of Apple ProRes at speeds far faster than real time on their Clipster product.[12]

On March 31, 2011, Telestream added support for ProRes encoding on Windows systems with Episode Engine, Vantage, and FlipFactory as a free upgrade to the current versions of these products. The system must be running on Windows Server 2008 and be able to support this feature. ProRes video capturing and output to tape is available in Telestream's Pipeline network encoder.

On 29 October 2011, FFmpeg introduced a free encoder, enabling ProRes 422 encoding on all FFmpeg supported platforms.

At the April 2012 NAB Show, Brevity introduced a customized algorithm for the accelerated transport and encoding of ProRes files.[13]

Frame layout[edit]

A typical Apple ProRes 422 frame has the following layout:

Frame container atom

Frame header

Picture 1

Picture 2 (interlaced frames only)

Supported Hardware[edit]

As of July 2014, ARRI announced support for the new Apple ProRes 4444 XQ, the highest-quality version of Apple ProRes to date, which will be available in the next Software Update Packet for Arri ALEXA cameras. ARRI ALEXA XT cameras and ALEXA Classic cameras with the XR Module will gain Apple ProRes 4444 XQ capability with ARRI's Software Update Packet SUP 10, which is scheduled for an open beta in July and a final release in August. ALEXA XR/XT cameras will support ProRes 4444 XQ in both HD and 2K resolutions. The ALEXA XR/XT cameras will be the world's first cameras capable of encoding ProRes 4444 XQ.[14]

At NAB 2012, Blackmagic announced Apple ProRes recording support for their HyperDeck SSD recorders, and Brevity announced a GPU-based ProRes transcoder with simultaneous accelerated file transport.[15]

As of June 2011, several hardware-based ProRes encoders exist, from AJA[16] (IO HD FireWire 800 interface; Ki Pro and Ki Pro Mini portable recorders), Atomos[17] (Ninja and Samurai recorders), Sound Devices (PIX series recorders), and Fast Forward Video[18] (Sidekick recorder).

See also[edit]

References[edit]

  1. ^ Final Cut Pro 6 - Broad Format Support.
  2. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  3. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  4. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  5. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  6. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  7. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  8. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  9. ^ "Apple ProRes White Paper". Apple. June, 2014. 
  10. ^ "Arri Group: News". Arri. Retrieved July, 2014. 
  11. ^ Apple: ProApps Codecs
  12. ^ http://www.dvs.de/products/video-systems/clipster.html
  13. ^ "NAB 2012: Brevity Emerges From Stealth Mode". Sports Video Group. 2012-04-16. Retrieved 2012-05-14. 
  14. ^ "Arri Group: News". Arri. Retrieved July, 2014. 
  15. ^ http://sportsvideo.org/main/blog/2012/04/16/nab-2012-brevity-emerges-from-stealth-mode/
  16. ^ AJA
  17. ^ Atomos
  18. ^ Fast Forward Video

External links[edit]