Avid DNxHD (Digital Nonlinear Extensible High Definition) is a lossy high-definition video post-production codec engineered for multi-generation compositing with reduced storage and bandwidth requirements for audio, video and metadata (including subtitles and closed captioning) source material. It is an implementation of the SMPTE VC-3 standard. The DNxHD codec was developed by Avid Technology, Inc., and first supported in Avid DS Nitris in 2004 and approved as compliant with the SMPTE VC-3 standard in 2008.
Avid DNxHD is engineered to create mastering-quality HD media at reduced file sizes, increasing real-time HD productivity, whether using local storage or in real-time collaborative workflows. While native HD camera compression formats are efficient, they aren’t engineered to maintain quality during complex post production effects processing.
Uncompressed HD delivers superior image quality, but data rates and file sizes can greatly hamper workflow. Avid DNxHD allows for optimal mastering picture quality, minimal degradation over multiple generations, reduced storage requirements, realtime HD sharing and collaboration for editing as well as for other uses such as archiving and transcription, improved multi-stream performance, and allows the QuickTime HD codec to be exported much faster from Media Composer than other QT codecs, offers superior playback performance and picture quality in Pro Tools.
DNxHD is a intended to be usable as both an intermediate format suitable for use while editing and as a presentation format. DNxHD data is typically stored in an MXF container, although it can also be stored in a QuickTime container. The source code for the Avid DNxHD codec is licensable free of charge. QuickTime HD codec is downloadable free of charge for Mac OS X and Windows XP, Windows Vista and Windows 7. It has been commercially licensed to a number of companies including Ikegami, FilmLight, Harris Corporation, JVC, Seachange, and EVS Broadcast Equipment.
Ikegami’s Editcam camera system is unique in its support for DNxHD and records directly to DNxHD encoded video. Such material is immediately accessible by editing platforms that directly support the DNxHD codec. DNxHD is also supported by Arri Alexa, Blackmagic Design, HyperDeck Shuttle 2, HyperDeck Studio, Media Composer, NewsCutter, Symphony, Avid DS and Interplay Assist. A standalone QuickTime codec for Windows XP and Mac OS X is available to create and play QuickTime files containing DNxHD material.
DNxHD is very similar to JPEG. Every frame is independent and consists of VLC-coded DCT coefficients. The DNxHD codec was submitted to the SMPTE organization as the framework for the VC-3 family of standards and was approved as SMPTE VC-3 after a two year testing and validation process in 2008 and 2009.