Avid DNxHD, which stands for "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. It is an implementation of SMPTE VC-3 standard. DNxHD codec was developed by Avid Technology, Inc.

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 offers a choice of three user-selectable bit rates: 220 Mbit/s with a bit depth of 10 or 8 bits, and 145 or 36 Mbit/s with a bit depth of 8 bits.

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 VC3 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.