OmniTek Ultra XR, User Manual

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Ultra XR User Guide C–9 XR-56-201 5
Applic
ations
Cable / Data view
4K Data Construction
Many adopters have implemented systems using Quad Link (4 x 3G-SDI) to transfer the image as 4
quadrants of 1920 x 1080 to assemble the 4K / UHDTV 3840 x 2160 image using the Square Division
approach. All of the current SMPTE specifications covering 4K / UHDTV, however, have defined the 2
sample interleave method which uses 4 sub images and alternates the samples every 2 pixels (as a
luma and chroma sample pair) and every line instead of splitting the image into 4 quadrants. The 2
Sample Interleave method being preferred as the receiving equipment does not require a frame store
to reassemble the image and this does not introduce any significant delay into the video path.
The SMPTE standards are complicated by the number of different interfaces combinations that are
available which can make it difficult to understand and check that the correct data is in the correct
place when converting between different cable interfaces. For example for Quad-link 3GA there are 4
streams (which are essentially 4 HD images) and for all other 4K standards there are 8 ‘streams’. For
Quad-link 3GA the luma and chroma channels are assembled in pairs on 4 stream rather than on the 8
separate streams.
The example below shows how a Square Division or 2 Sample Interleave source is mapped on to a
12G-SDI cable.
1
0
1 2 2 1 1 2 2
3 3 4 4 3 3 4 4
1 1 2 2 1 1 2 2
3 3 4 4 3 3 4 4
1 1 2 2 1 1 2 2
3 3 4 4 3 3 4 4
3839/4095
0
2159
Sub Image 1 Sub Image 2
Sub Image 3 Sub Image 4
0 3839/4095 1919|2047
0
2159
1079
1080
2 Sample Interleave
Square Division
Sub Image 1
EA
V
SA
V HANC
Data
0
1919/
2047
Sub Image 2
EA
V
SA
V HANC
Data
Sub Image 3
EA
V
SA
V HANC
Data
Sub Image 4
EA
V
SA
V HANC
Data
Source Image ST425-5 80-bit Virtual Interface Mapping
Data Stream 1
Data Stream 2
Data Stream 3
Data Stream 4
Data Stream 5
Data Stream 6
Data Stream 7
Data Stream 8
Mul ti plex
12G-SDI 10bit
Interface ST 2082-1
Cable
Even though there are 4 sub-images shown in the diagram above, these are virtual images that do not
actually represent 4 cables. From these 4 ‘sub images’ come 8 ‘streams’ (a luma and chroma pair for
each virtual image). These streams are then multiplexed on to the physical cable(s) in the data order
defined by the cable interface being used.