FORMAT



DNxHD

The DNxHD video compression format was originally developed by Avid as HD became a media standard.

This codec is used primarily in video editing and in complex multi-generation operations, which are common in today's collaborative post and broadcast environments. DNxHD is a lossy intraframe codec . This means that each frame is complete in and of itself and independently encoded. This codec offers a number of advantages including high quality mastering at a reduced bitrate, minimal loss through generations and extensive industry-wide support (over 60 manufacturers currently support DNxHD). 

DNxHD Family

  • DNxHD 444: 1920x1080, 10-bit, 4:4:4; 440Mbit/s, 'optically lossless compression', capable to replace HDCAM SR
  • DNxHD 220x: 1920x1080, 10-bit, 4:2:2, up to 220Mbit/s (depending on chosen framerate, i.e. 1080p24 -> 175Mbit/s)
  • DNxHD 220: 1920x1080, 8-bit, data rate depending on chosen framerate, approx equivalent to DNxHD 220x
  • DNxHD 145: 8-bit 145Mb/s
  • DNxHD 100: 1440 x 1080 or 960 x 720 8-bit at 4:2:2 for lower data storage or fast transfer requirements (please refer to the table below concerning sub-sampled frame sizes, when lower data rates are in use)
  • DNxHD 36: 1920 x 1080, 8-bit, 4:2:2 at 36Mbit/s - proxy copy for editing only.

Cameras like the ARRI Alexa , and external recording systems offer the ability to record directly into DNxHD.

DNxHD saves encoded video data in a standard MXF container, ensuring that all applications that understand MXF can access the data it contains. It can also make use of the QuickTime container for use in applications such as Final Cut Pro. DNxHD is an implementation of the SMPTE VC3 standard .

In 2014 Avid introduced the DNxHR codec to respond to the growing need for the processing of higher than HD-resolution material. This codec supports resolutions up to 4K and is backward compatible. The advantages described for DNxHD also apply to DNxHR.

DNxHD Summary

  • VIDEO
  • Quantising: 8 bit / 10 bit (DNxHD 220x or higher)
  • Codec: DCT / DNxHD
  • Chroma Subsampling: 4:2:2 (DNxHD = 4:4:4)
  • Aspect Ratio: 16:9
  • Resolution:
  • 1920x1080 (Note: DNxHD 80, 85, 100 use sub-sampled frame sizes of 1440x1080)
  • 1280x720 (Note: DNxHD 45, 50, 85, 100 use sub-sampled frame sizes of 960x720)
  • Framerate: All common rates from the PAL and NTSC standards
  • Datarate: see table on DNxHD family
  • RECORDING MEDIA
  • File Format: .mov or .mxf container
  • Recording Media: any file storage
  • Recording Duration / Capacity: depedent on storage system