DNxHD
DNxHD® ( D igital N onlinear E x tensible H igh D efinition ) is one of Avid developed data format for lossy compressed video data . DNxHD is used for video editing in post-production (intermediate format), a camera from Ikegami uses DNxHD as the original format . A DNxHD data stream is typically packed in an MXF container, but can also be wrapped in other container formats. DNxHD is the basis of the SMPTE specification VC-3. The Institute for Broadcasting Technology (IRT) has approved the DNxHD format along with others ( AVC-Intra , Apple ProRes , HDCAM SR ) for use in high-resolution premium productions from ARD , ZDF , ORF and SRG and certifies it even at low data rates good multi-generation behavior.
technical structure
Technically, DNxHD is structured as an intraframe video format (see also Motion JPEG ) in which each image is encoded independently of its neighboring images. This allows the complexity of the video format to be kept low, but at the expense of the lowest possible data rate. Each image has a time stamp and a unique ID. DNxHD uses 4: 2: 2 color subsampling and supports an alpha channel .
Formats
The following resolutions and data rates are offered for PAL .
| format | fps | Color depth in bits | designation | Data rate in Mbit / s |
|---|---|---|---|---|
| 1080i / 50 | 25th | 10 | DNxHD 185x | 184 |
| 1080i / 50 | 25th | 8th | DNxHD 185 | 184 |
| 1080i / 50 | 25th | 8th | DNxHD 120 | 121 |
| 1080p / 25 | 25th | 10 | DNxHD 185x | 184 |
| 1080p / 25 | 25th | 8th | DNxHD 185 | 184 |
| 1080p / 25 | 25th | 8th | DNxHD 120 | 121 |
| 1080p / 25 | 25th | 8th | DNxHD 36 | 36 |
| 1080p / 24 | 24 | 10 | DNxHD 175x | 176 |
| 1080p / 24 | 24 | 8th | DNxHD 175 | 176 |
| 1080p / 24 | 24 | 8th | DNxHD 115 | 116 |
| 1080p / 24 | 24 | 8th | DNxHD 36 | 36 |
| 720p / 50 | 50 | 10 | DNxHD 175x | 175 |
| 720p / 50 | 50 | 8th | DNxHD 175 | 175 |
| 720p / 50 | 50 | 8th | DNxHD 115 | 175 |
| 720p / 25 | 25th | 10 | DNxHD 90x | 92 |
| 720p / 25 | 25th | 8th | DNxHD 90 | 92 |
| 720p / 25 | 25th | 8th | DNxHD 60 | 60 |
With a resolution of 1280 × 720 there is no 24 fps mode, only 23.976 fps.
Products
The source code of DNxHD can be viewed and used freely, but a commercial implementation requires a license. A QuickTime plug-in from Avid allows encoding and decoding of DNxHD on Windows and Apple platforms. The open source project FFmpeg supports DNxHD from version 0.5, whereby DNxHD with 8 bit color depth can also be encoded and decoded on Linux platforms; 10 bit color depth has been supported since July 2011.
In addition to Avid, other manufacturers also support DNxHD:
- Hard disk recorder AJA KiPro
- Camera Ikegami Editcam HD
- Digital video recorder from Cinedeck and OpenCubeTech and Blackmagic Design HyperDeck Shuttle 2
- Graphics card from Matrox
- Nethra integrated circuit
HD intraframe video formats
- Apple ProRes , an HD intraframe video format from Apple for video editing in post-production.
- AVC-Intra , an HD intraframe video format from Panasonic for recording devices, but also for video editing.
- Motion-JPEG 2000 , an HD intraframe video format based on JPEG 2000 . Use in digital cinema .
Footnotes
- ↑ Message about the support of 10 bit color depth
- ↑ Ikegami camera ( Memento of the original from August 5, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Cinedeck digital video recorder
- ↑ OpenCubeTech digital video recorder
- ↑ Blackmagic Design HyperDeck Shuttle 2
- ↑ http://www.matrox.com/video/en/press/releases/avid_dnxhd_codec_support_dsx/ ( Memento from June 19, 2012 in the Internet Archive )
- ↑ Nethra Chip Encoder / Decoder ( Memento of the original from July 31, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
Web links
- Avid White Paper on DNxHD (PDF; 311 kB)
- Institute for Broadcasting Technology - Investigations into compression and conversion in HDTV
- Avid DNxHD website
- FFmpeg options for DNxHD ( Memento from October 21, 2013 in the Internet Archive )