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Plus d’informations sur le DNX HD, format vidéo HD de Avid

Tout savoir sur le format DNX HD, codec Made in Avid utilisé sur les machines de la famille DNA. Voir aussi la vidéo de présentation DNX HD en « format streamé » : Flash flv / Windows Media 9 / QuickTime

The Avid DNxHD codec. High definition without the high overhead.

Gorgeous quality. Amazing efficiency. Technology that challenges old perceptions and inspires new possibilities. That’s the thinking behind Avid DNxHD encoding technology: a solution that puts HD within easy reach of postproduction professionals who stake their reputations on uncompromised quality. With nearly 20 years of industry expertise behind it, the Avid DNxHD codec is engineered to withstand the rigors of multi-generational processing and leverage today’s collaborative networks.

Avid DNxHD Product Brief

Voir aussi la vidéo de présentation DNX HD en « format streamé » :

 Flash flv / Windows Media 9 / QuickTime

Engineered for quality and efficiency

Avid DNxHD is a revolutionary mastering-quality HD codec engineered for multi-generation compositing with reduced storage and bandwidth requirements. For example:

  • Avid DNxHD 145 8-bit media delivers HD quality while requiring approximately 20% less storage capacity than 8-bit uncompressed standard definition media.
  • The reduced bandwidth of Avid DNxHD encoding enable single editing systems to work in HD with a simple 4- or 8-way drive stripe set or even a single drive.
  • Avid DNxHD encoding enables the first truly collaborative real-time HD environment with Avid Unity MediaNetwork systems.
  • Avid DNxHD encoding supports Avid’s Emmy® award winning Multicamera functionality with up to three real-time streams of Avid DNxHD 145.
  • By offering a wide range of mastering resolutions and a choice of data rates, time consuming offline-to-online recapture can be eliminated and bandwidth requirements are optimized.

Uncompressed high-definition (HD) data rates require nearly seven times the bandwidth and storage resources as uncompressed standard-definition (SD) media. Avid DS Nitris systems have the power to handle uncompressed HD but, if you want to go beyond standalone HD editing, the high data rates of uncompressed HD media make it difficult to implement an efficient, collaborative, and profitable workflow using multiple systems connected to a shared storage network.

Avid DNxHD encoding offers mastering-quality HD media at dramatically reduced file sizes, shattering the barriers to real-time HD productivity, whether using standalone local storage or in real-time collaborative HD workflows over Avid Unity MediaNetwork systems . In fact, the efficiency of Avid DNxHD encoding makes it possible to work with mastering-quality HD media on notebook systems.

To maximize efficiency, users can pick the Avid DNxHD bit depths and data rates that most closely match those of the source media. Or they can choose to encode 8-bit HD media as 10-bit Avid DNxHD media to maintain pristine image quality over multiple generations of postproduction processing. The increased bit depth provides the additional dynamic range necessary for precise color correction and contrast adjustments without clipping. Once postproduction is completed, the media can be output in the same format as the source media, or in other HD formats as needed.

Engineered for postproduction processing

The Avid DNxHD codec is specifically designed for nonlinear editing and multi-generation compositing, including collaborative postproduction and broadcast news environments. It offers a choice of 8- or 10-bit sampling, three user-selectable bit rates, and the ability to maintain image quality more effectively than other HD codecs. The chart below compares Avid DNxHD encoded media to other popular HD formats:

Most popular compressed HD formats do not natively support the full HD raster. Most employ raster downsampling to reduce bandwidth. But downsampling can make HD images look softer, reduces the high frequency detail in the image, and can generate unwanted artifacts over multiple generations of postproduction processing. Avid DNxHD encoding maintains the full raster of the active video, sampling every available pixel within the image. The table below shows the reduction in image size that is a characteristic of raster downsampling used in other HD compression schemes:

Format Avid DNxHD 145 DVCPRO HD HDCAM Avid DNxHD 220 HDCAM SR

Bit depth

8- bit

8-bit

8-bit

8-and 10- bit

10-bit

Sampling

4:2:2

4:2:2

3:1:1

4:2:2

4:2:2 or 4:4:4

Bandwidth

145 Mb/sec

100 Mb/sec

135 Mb/sec

220 Mb/sec

440 Mb/sec

Format
Bit Depth
Resolution / Frame Rate
Y
Chroma
Using DNxHD
Restored Y*

Bit Depth

From

To

From

To

From

To

HDCAM

8

1080i/
60

1920

1440

960

480

1440

1920

HDCAM

8

1080p/ 23.976

1920

1440

960

480

1440

1920

HDCAM

8

1080p/
24

1920

1440

960

480

1440

1920

HDCAM

8

1080p/
25

1920

1440

960

480

1440

1920

DVCPRO HD

8

1080i/ 59.94

1920

1280

960

640

1280

1920

DVCPRO HD

8

1080i/ 50

1920

1440

960

720

1440

1920

DVCPRO HD

8

720p/
59.94

1280

960

640

480

960

1280

DVCPRO HD

8

720p/ 23.976

1280

960

640

480

960

1280


*C values are also restored

Engineered for open data interchange

Avid DNxHD technology is based on the MXF standard, ensuring that media can be exchanged with any other MXF-compliant system. In addition, the source code for the Avid DNxHD codec will be licensable free of charge, available through the Avid Website as a download to any user who wants to compile it on any platform. Now users and developers can be confident that media files will always be accessible – with or without Avid equipment.

Engineered for the future

Avid DNxHD encoding is a scaleable solution that will allow Avid to add different formats, resolutions, and data rates as required by the marketplace. As the demands move to higher and lower bit rates, there will be an Avid DNxHD solution to meet those needs.

resources

HD Handbook / HD from A to Z. Get your free handbook today.

Whitepaper: Avid DNxHD / Read how Avid DNxHD significantly reduces storage and bandwidth requirements while providing mastering-quality HD media.

HD workflow / Learn how Avid DNxHD enables collaborative workflow.

HD Market brief / Avid is helping today’s artists, editors, producers, and executives make the transition to HD.

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