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 ...
high-definition video post-production codec
A codec is a device or computer program 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 on a signal or ...
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 is ...
with reduced storage and bandwidth requirements. It is an implementation of
SMPTE
The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and executives working in the m ...
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 MXF or mxf may refer to:
* Material Exchange Format, a container format for professional digital video and audio media
* MXF, the IATA and FAA LID code for Maxwell Air Force Base, Alabama, United States
* mxf, the ISO 639-3 code for Malgbe language ...
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
EVS Broadcast Equipment SA is a Belgian company that manufactures live outside broadcast digital video production systems. Their XT-VIA production video servers enable the creation, editing, exchange and playout of audio and video feeds.
Tape ...
.
On September 14, 2014, at the Avid Connect event in
Amsterdam
Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the capital and most populous city of the Netherlands, with The Hague being the seat of government. It has a population of 907,976 within the city proper, 1,558,755 in the urban ar ...
,
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
, 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 screen ve ...
, such as
2K and
4K.
On December 22, 2014, Avid Technology released an update for
Media Composer
Avid Media Composer is a film and video editing software application or non-linear editing system (NLE) developed by Avid Technology. Initially released in 1989 on Macintosh II as an offline editing system, the application has since evolved to ...
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
Avid Xpress Pro was a non-linear video editing software aimed at professionals in the TV and movie industry. It was available for Microsoft Windows PCs and Apple Macintosh computers.
Xpress Pro included many of the high-end editing features o ...
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
Editcam is a professional digital camera system manufactured by Ikegami and first introduced in 1995, available both as professional camcorders and modular dock recorders. It is the first ever tapeless field acquisition device and has evolved int ...
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 Alexa
The Arri Alexa (stylised as ΛLEXΛ) is a digital motion picture camera system developed by Arri. First introduced in April 2010, the camera was Arri's first major transition into digital cinematography after previous efforts such as the Arrif ...
br>
supports DNxHD since November 2011 Blackmagic Design
Blackmagic Design Pty Ltd. is an Australian digital cinema company and hardware manufacturer based in Port Melbourne, Victoria, Australia. It designs and manufactures broadcast and cinema hardware, most notably high-end digital-movie camer ...
HyperDeck Shuttle 2 and HyperDeck Studio support DNxHD as of 2012
AJA Video Systemshas 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 upgrade to its predecessors, Windows 2000 for high-end and ...
and
Mac OS X
macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...
is available to create and play QuickTime files containing DNxHD material.
Since September 2007, the
open source 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 of vid ...
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 ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...
non-linear video editor
Non-linear editing is a form of offline editing for audio, video, and image editing. In offline editing, the original content is not modified in the course of editing. In non-linear editing, edits are specified and modified by specialized sof ...
s
Cinelerra
Cinelerra is a video editing and Digital compositing, composition program (an NLE, Non-Linear Editor) designed for Linux. It is free software distributed under the open source GNU General Public License. In addition to editing, it supports advance ...
and
Kdenlive
Kdenlive (; acronym for ''KDE Non-Linear Video Editor'') is a free and open-source video editing software based on the MLT Framework, KDE and Qt. The project was started by Jason Wood in 2002, and is now maintained by a small team of develope ...
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. 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
GUID
A universally unique identifier (UUID) is a 128-bit label used for information in computer systems. The term globally unique identifier (GUID) is also used.
When generated according to the standard methods, UUIDs are, for practical purposes, uni ...
s and timestamp. The frame header is packed into big-endian
dword
In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized datum handled as a unit by the instruction set or the hardware of the processor. The number of bits or digits in a word (the ''word s ...
s. Actual frame data consists of packed
macroblocks The macroblock is a processing unit in image and video compression formats based on linear block transforms, typically the discrete cosine transform (DCT). A macroblock typically consists of 16×16 samples, and is further subdivided into transform ...
using a technique almost identical to
JPEG: 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
{{DEFAULTSORT:Dnxhd Codec
Film and video technology
SMPTE standards
Video codecs