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Apple ProRes

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This is an old revision of this page, as edited by Sergei.yakovlev (talk | contribs) at 12:46, 21 June 2013 (Moving article from /ProRes_422 to /ProRes (since it also includes information on ProRes 4444)). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

ProRes is a lossy video compression format developed by Apple Inc. for use in post production that supports up to 4k. It is the successor of the Apple Intermediate Codec and was introduced in 2007 with Final Cut Studio 2.[1]

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. 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 who offer similar bitrates which are also intended to be used as intermediate codecs. ProRes 422 is a DCT based[2] intra-frame-only codec and is therefore simpler to decode than distribution oriented formats like H.264.

ProRes 422

Key features

  • 4K, 2K, HD (up to 1920x1080), & SD resolutions
  • 4:2:2 chroma subsampling
  • 10-bit sample depth
  • I frame-only encoding
  • Variable bit-rate (VBR) encoding
  • Normal 147 Mbit/s and High-Quality 220 Mbit/s as well as ProRes (LT) 100Mbit/s for HD resolution at 60i
  • Normal 42 Mbit/s and High-Quality 63 Mbit/s for SD resolution at 29.97
  • ProRes 422 (Proxy) is a 36 Mbit/s proxy media version of HD video for editing offline.
  • Fast encoding and decoding (both at full size and half size)

ProRes 4444

ProRes 4444 is another lossy video compression format developed by Apple Inc. for use in post production. It was introduced with Final Cut Studio (2009) [3] as another in the company's line of intermediate codecs for editing material but not for final delivery. It shares many features with other codecs of Apple's ProRes family but provides better quality than its predecessors, particularly in the area of color.[4]

Key features

  • 4K, 2K, HD (up to 1920x1080), & SD resolutions
  • 4:4:4 chroma subsampling
  • up to 12-bit pixel depth
  • Variable Bit Rate (VBR)
  • Alpha Channel Support

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. [1]

Encoding

Installing Final Cut Pro will install the ProRes codecs for encoding files on OS X.

Apple released ProRes bundled with other pro codecs as a free download for OS X with QuickTime 7.6 and newer.[5]

At the April 2010 NAB show, DVS Digital Video Inc. 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.

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 [6]

Frame Layout

A typical ProRes 422 frame has the following layout: 

      Frame container atom

          Frame header

           Picture 1

Picture 2 (interlaced frames only)

ProRes hardware

The Arri Alexa has a built-in ProRes recording unit for its 1080p and 2K video streams, supporting ProRes 4444 and all ProRes 422 versions.

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

At NAB 2012, Blackmagic announced ProRes recording support for their HyperDeck SSD recorders, and Brevity announced a GPU-based ProRes transcoder with simultaneous accelerated file transport.[7]

See also

References

  1. ^ Final Cut Pro 6 - Broad Format Support.
  2. ^ Adcock, Gary (2009-03-03). "ProRes: A Closer Look". ProVideo Coalition. Retrieved 2009-03-12.
  3. ^ Final Cut Pro 7. Expanded ProRes Family
  4. ^ Apple ProRes White Paper July 2009
  5. ^ Apple: QuickTime-Codecs für ProApps
  6. ^ "NAB 2012: Brevity Emerges From Stealth Mode". Sports Video Group. 2012-04-16. Retrieved 2012-05-14.
  7. ^ http://sportsvideo.org/main/blog/2012/04/16/nab-2012-brevity-emerges-from-stealth-mode/
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