Avid DNxHD ("Digital Nonlinear Extensible High Definition") is a

lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...

post-production Post-production, also known simply as post, is part of the process of filmmaking, video production, audio production, and photography. Post-production includes all stages of production occurring after principal photography or recording indivi ...

codec A codec is a computer hardware or software component that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder o ...

developed by Avid for multi-generation

compositing Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live action, Live-action shooting for compositing ...

with reduced storage and bandwidth requirements. It is an implementation of

SMPTE The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded by Charles Francis Jenkins in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and e ...

VC-3 standard.

Overview

DNxHD is a video codec 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. On February 13, 2008, Avid reported that DNxHD was approved as compliant with the SMPTE VC-3 standard. DNxHD is intended to be an open standard, but as of March 2008, has remained effectively a proprietary Avid format. The source code for the Avid DNxHD codec is freely available from Avid for internal evaluation and review, although commercial use requires Avid licensing approval. It has been commercially licensed to a number of companies including Ikegami, FilmLight, Harris Corporation, JVC, Seachange, EVS Broadcast Equipment. On September 14, 2014, at the Avid Connect event in

Amsterdam Amsterdam ( , ; ; ) is the capital of the Netherlands, capital and Municipalities of the Netherlands, largest city of the Kingdom of the Netherlands. It has a population of 933,680 in June 2024 within the city proper, 1,457,018 in the City Re ...

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

, Avid announced the DNxHR codec to support resolutions greater than

1080p 1080p (1920 × 1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the sc ...

, such as 2K and 4K. On December 22, 2014, Avid Technology released an update for Media Composer that added support for 4K resolution, the Rec. 2020 color space, and a bit rate of up to 3,730 Mbit/s with the DNxHR codec.

Implementations

DNxHD was first supported in Avid DS Nitris (Sept 2004), then Avid Media Composer Adrenaline with the DNxcel option (Dec 2004) and finally by Avid Symphony Nitris (Dec 2005). Xpress Pro is limited to using DNxHD 8-bit compression, which is either imported from file or captured using a Media Composer with Adrenaline hardware. Media Composer 2.5 also allows editing of fully uncompressed HD material that was either imported or captured on a Symphony Nitris or DS Nitris system. 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. The Arri Alexabr>supports DNxHD since November 2011
Blackmagic Design HyperDeck Shuttle 2 and HyperDeck Studio support DNxHD as of 2012
AJA Video Systems
has supported the DNxHD codec in its Ki Pro Mini and Ki Pro Rack recorders and players since 2012. A standalone QuickTime codec for both

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...

and

Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

is available to create and play QuickTime files containing DNxHD material. Since September 2007, the

open source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

FFmpeg FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing vide ...

project is providing 8-bit VC-3/DNxHD encoding and decoding features thanks to BBC Research who sponsored the project and Baptiste Coudurier who implemented it. In July 2011, FFmpeg added 10-bit encoding support. DNxHD support is included in stable version 0.5 of FFmpeg, released on March 10, 2009. This allows

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

non-linear video editors Cinelerra and Kdenlive to use DNxHD. At the April 201
NAB show
Brevity introduced a customized algorithm for the accelerated transport and encoding of DNxHD files.

Technical details

DNxHD is very similar to

JPEG JPEG ( , short for Joint Photographic Experts Group and sometimes retroactively referred to as JPEG 1) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degr ...

. Every frame is independent and consists of VLC-coded DCT coefficients. The header consists of many parts and may include quantization tables and 2048 bits of user data. Each frame also has two GUIDs and timestamp. The frame header is packed into big-endian dwords. Actual frame data consists of packed macroblocks using a technique almost identical to

: DC prediction and variable-length codes with run length encoding for other 63 coefficients. DC coefficient is not quantized. The codec supports alpha channel information.

VC-3

The DNxHD codec was submitted to the SMPTE organization as the framework for the VC-3 family of standards. It was approved as SMPTE VC-3 after a two-year testing and validation process in 2008 and 2009: * SMPTE 2019-1-2008 VC-3 Picture Compression and Data Stream Format * SMPTE 2019-3-2008 VC-3 Type Data Stream Mapping Over SDTI * SMPTE 2019-4-2009 Mapping VC-3 Coding Units into the MXF Generic Container * RP (Recommended Practices) 2019-2-2009 VC-3 Decoder and Bitstream Conformance

References

External links

Avid DNxHD Codec FeaturesAvid Codec DownloadsNethra VC-3 codec chip
{{Compression Software Implementations Film and video technology SMPTE standards Video codecs