Apple ProRes

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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[edit]

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. 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[edit]

Key features[edit]

  • 4K, 2K, HD (up to 1920×1080), & SD resolutions
  • 4:2:2 chroma subsampling
  • 10-bit sample depth
  • I frame-only encoding
  • Variable bitrate (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[edit]

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[edit]

  • 5K, 4K, 2K, HD (up to 1920×1080), & SD resolutions[5]
  • 4:4:4 chroma subsampling
  • Up to 12-bit sample depth
  • Variable bitrate (VBR) encoding
  • Alpha channel support

Playback[edit]

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[edit]

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[edit]

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 download for users with "qualifying copies of Final Cut Pro, Motion, or Compressor" installed, for OS X with QuickTime 7.6 and newer.[6]

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.[7]

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.[8]

Frame layout[edit]

A typical ProRes 422 frame has the following layout:

Frame container atom

Frame header

Picture 1

Picture 2 (interlaced frames only)

ProRes hardware[edit]

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[9] (IO HD FireWire 800 interface; Ki Pro and Ki Pro Mini portable recorders), Atomos[10] (Ninja and Samurai recorders), Sound Devices (PIX series recorders), and Fast Forward Video[11] (Sidekick recorder).

At NAB 2012, Blackmagic announced ProRes recording support for their HyperDeck SSD recorders as well as on board recording on the Blackmagic Cinema Camera, and Brevity announced a GPU-based ProRes transcoder with simultaneous accelerated file transport.[12]

In 2013 Convergent Design introduced their Odyssey7 and Odyssey7Q monitor/recorders that can record in Apple ProRes 422 (HQ) and are certified by Apple. [13]

See also[edit]

References[edit]

External links[edit]