Recommended Systems for 8K Playback. Part 2: Using 12G SDI
By Mauricio Alvarez-Mesa, PhD — Spin Player is a software media player that allows to play very high resolution video including 4K, 8K, and 16K using standard PC systems. The Player is based on Spin Digital high-performance HEVC/H.265 decoder and Spin Digital optimized video rendering engine.
An important component of the video playback chain is the output interface. Spin Digital currently supports video rendering with GPUs that include up to 4 DisplayPort outputs which can be combined to form a single 8K frame, or GPUs including one HDMI 2.1 output. The use of the HDMI 2.1 interface facilitates the transmission of the 8K signal to the display as a single cable is needed. More information about the recommended systems for 8K playback using GPUs can be found in a previous edition of our tech blog.
With GPUs, however, it is not always possible to have a full control of the video output as the device can perform automatic color conversions. In addition, HDR formats are not properly supported when using multiple DisplayPort outputs as in the case of 8K playback.
Spin Player now supports 12G SDI output for 8K HEVC video playback. The SDI support is addressed for professionals requiring maximum control of the video processing and display chain. In this tech blog we describe the use cases, requirements, and systems needed for 8K playback using SDI interfaces
12G SDI for 8Kp60, 8Kp120, and Beyond
12G SDI offers the bandwidth required for the transmission of uncompressed 8K (7680x4320px) video at 60 Hz with 4:2:2 10-bit format, by using a quad-link 12G configuration as specified in the SMPTE ST 2082-12 standard.
For 8Kp60 the 12G interface requires a single SDI board and only 4 12G SDI cables as opposed to two devices and 16 cables as with 3G SDI.
12G SDI can also be used for 8Kp120 playback for High Frame Rates (HFR) or 8K 3D (stereoscopic) applications by using two 12G SDI boards. Spin Player already supports this feature called multi-device, which allows to combine several output devices to create a single output. This feature supports different operation modes including: clone (same output in all devices), tiled (single video frame across multiple devices), and alternate (interleaved output among devices).
By using multiple 12G SDI cards it is also possible to support resolutions beyond 8K including 16Kp60 for very-large scale visualization systems.
System Configuration for 8K Playback with 12G SDI
For 8Kp60 and 8Kp120 HEVC decoding Spin Digital recommends, respectively, the Intel Xeon Gold 6330N processor (28 cores) and two Intel Xeon Gold 5318N (2x 24 cores) processors. For video rendering over 12G SDI, it is recommended to use either the AJA 12G Kona 5 board or the AJA Corvid 44 12G board.
When using SDI as output interface, the video rendering process (color conversion, pixel format conversion, chroma subsampling, etc) is performed on the CPU. Spin Digital has developed an optimized library of video processing filters called SpinFilter for CPU video processing and rendering. Spin Player selects and configures automatically this optimized CPU rendering library.
Display Systems for 8Kp60
Spin Player with 12G SDI output can be used for 8K playback on 8K TVs (using SDI to HDMI conversion) or 8K projectors that accept 12G SDI directly.
8K TV with HDMI Input
Some 8K TV models accept 4x HDMI 2.0 inputs. A player with SDI interface can be used in combination with 4x 12G SDI to HDMI 2.0 converters that can be acquired commercially from different vendors including AJA or Black Magic. Alternatively, the Astrodesign converter can be used for 8K TVs supporting HDMI 2.1.
8K Projector with SDI Input
Some recent projectors support 8K resolution and accepts directly 12G SDI as input interface. Spin Digital presented in May 2019 a demonstration of 8K playback at the Festival de Cannes using Spin Player with 12G SDI and the Insight laser 8K projector from Digital Projection.
Display Systems for 8Kp120
Spin Player with 12G SDI output can be used for 8K HFR or 3D (stereo) playback on devices that accept 8Kp120 SDI input. The recommended format is called alternate rendering, in which 8Kp120 is presented as 2x 8Kp60 using 2 SDI devices each one taking care of the odd and even frames.
Note and Disclaimer
These recommendations are based on internal tests performed by Spin Digital. This information is provided “as is” and it does not imply any warranty or assurance. If you have more specific requirements, please contact us.
Spin Digital and Spin Player are trademarks of Spin Digital Video Technologies GmbH.
Other trademarks remain the property of their owners, and are used here for descriptive purposes.