Alain Legault of Hardent discusses the challenges of designing products to meet the demands of current and future displays and highlights how DSC compression offers an innovative solution to deal with these challenges.

1. Alain Legault
Hardent
Create Higher Resolution
Displays With VESA Display
Stream Compression

2. © 2017 MIPI Alliance, Inc.
What Is VESA DSC?
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3. © 2017 MIPI Alliance, Inc.
Why Is VESA DSC Needed?
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Processor TX
Port
Display
Module
RX
Port
To DisplayVideo In
Mobile application processor MIPI DSISM DDIC
Computer GPU card DisplayPort cable Computer monitor
Car application processor Proprietary transport Car infotainment display

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Display Resolution Growth
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10x / 5 years
3x / 5 years
G
A
P

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VESA DSC Block Diagram
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Source: VESA DSC white paper

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VESA DSC Algorithm
• Intra-frame Constant Bit Rate (CBR) encoder
• Based on Delta Pulse Code Modulation (DPCM)
• Mid Point (MPP), Block Predictor (BP)
• Modified Median Adaptive Predictor (MMAP)
• Indexed Color History (ICH)
• Requires a single line of pixel storage + rate buffer
– Ultra-low latency
• Visually lossless compression between 2x – 3x
• Video quality excellent with all types of content
– Natural and test images, text, and graphics
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7. © 2017 MIPI Alliance, Inc.
PHY Speed / Display Resolution
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Resolution
FHD
(1080x1920)
WQHD
(1440x2560)
WQXGA
(1600x2560)
UHD
(2160x3840)
WQUXGA
(2400x3840)
5K
(2880x5120)
8K
(4320x8192)
Bandwidth 3.58Gbps 6.37Gbps 7.08Gbps 14.33Gbps 15.93Gbps 25.49Gbps 61.16Gbps
No compression 3 lanes 6 or 8 lanes 6 or 8 lanes N/A N/A N/A N/A
2x compression 2 lanes 3 lanes 3 lanes 8 or 6 lanes 8 or 6 lanes N/A N/A
3x compression 1 lane 2 lanes 2 lanes 4 lanes 4 lanes 8 lanes N/A
MIPI D-PHYSM v1.1 1.5 Gbps / lane
Resolution
FHD
(1080x1920)
WQHD
(1440x2560)
WQXGA
(1600x2560)
UHD
(2160x3840)
WQUXGA
(2400x3840)
5K
(2880x5120)
8K
(4320x8192)
Bandwidth 3.58Gbps 6.37Gbps 7.08Gbps 14.33Gbps 15.93Gbps 25.49Gbps 61.16Gbps
No compression 2 lanes 3 lanes 3 lanes 8 or 6 lanes 8 lanes N/A N/A
2x compression 1 lane 2 lanes 2 lanes 3 lanes 4 lanes 8 or 6 lanes N/A
3x compression 1 lane 1 lane 1 lane 2 lanes 3 lanes 4 lanes N/A
MIPI D-PHY v1.2 2.5 Gbps / lane

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MIPI DSI Link Compression
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TX
Port
RX
Port
To DisplayVideo In
Processor
GPU
DSC
Encoder
DSC
Decoder
Display
Module
Frame
Buffer

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VESA DSC Task Group 2017

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VESA DSC Standard Availability and Support
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Source: VESA

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Transport Standards Using VESA DSC
• MIPI DSI 1.2
• eDisplayPort 1.4b
• DisplayPort 1.4
• HDMI 2.1
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Why Adopt VESA DSC?
• Visually lossless picture quality for all content
– Photos, videos, text, graphics, and test patterns
• Increases data transport capacity by up to 3X
• Compatible with major transport standards
– MIPI DSI, DisplayPort 1.4, HDMI 2.1
• Ultra-low latency
• Scalable display resolution, frame rate, and colour depth
– Up to 8K @ 120Hz with HDR
• Reduces power consumption, system costs, and EMI
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13. © 2017 MIPI Alliance, Inc.
DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
Application
Processor
MIPI DSI
Tx
MIPI DSI
Rx
MIPI DSI
Rx
DSC
Decoder
SDRAM
Display Driver
IC
Frame Buffer
SDRAM SDRAM

14. © 2017 MIPI Alliance, Inc.
DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
Application
Processor
MIPI DSI
Tx
MIPI DSI
Rx
MIPI DSI
Rx
DSC
Decoder
SDRAM
Display Driver
IC
Frame Buffer
SDRAM SDRAM
Remove
MIPI Tx + PHY
MIPI Rx + PHY

15. © 2017 MIPI Alliance, Inc.
DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
Application
Processor
MIPI DSI
Tx
MIPI DSI
Rx
MIPI DSI
Rx
DSC
Decoder
SDRAM
Display Driver
IC
Frame Buffer
SDRAM
Remove
SDRAMs
SDRAM

16. © 2017 MIPI Alliance, Inc.
DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
Application
Processor MIPI DSI
Rx
DSC
Decoder
Display Driver
IC
Frame Buffer
SDRAM
Less power
Smaller footprint
Lower costs

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Products Using VESA DSC
Qualcomm Snapdragon 820 NVIDIA Tegra X1

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VESA DSC in Consumer Electronics Applications
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19. © 2017 MIPI Alliance, Inc.
Image Source: MIPI Alliance
Use Case: Mobile and Tablet Applications
• Application
processor
• DDIC (Display Driver
IC) and touch panel
controller
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DSC Decoder
Display
Driver IC
MIPI DSI
Transport
Lanes
Application
Processor
MIPI DSI and
D-PHY
MIPI DSI and
D-PHY
DSC Encoder
GPU
High-Definition
Display

20. © 2017 MIPI Alliance, Inc.
DISPLAY
Display I/F
MIPI
DSI
Enet
I/F
IP
Decap
Disp
Ctlr
DSC
Dec
Telematic
Hub
Hub
Infotainment
Hub
HubHub Hub
Sensor I/F
MIPI
I3CSM
IP
Encap
Enet
I/FSENSOR
Camera I/F
MIPI
CSISM
Enet
I/F
IP
EncapISP
DSC
Enc
CAMERA
Use Case: In-Car Video Applications
• Application processor
• Infotainment display module
• Video cameras
• HDMI sources
• Ability to transport multiple
video sources simultaneously
• Automotive serial interfaces
and transport
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Use Case: AR / VR Head-Mounted Display
• Video capture
• Application
processor and
GPU
• Micro-display
driver IC
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SDRAMSDRAMSDRAM
Shared Memory Bus
APU/GPU
DSC
Encoder
DSC
Decoder
Capture System
DSC
Encoder
DMA
Ctrl
MIPI CSI
MIPI CSI
µDisplay L µDisplay R
LPDDR
ISP
ISP
DMA
Ctrl
DMA
Ctrl
µDisplay Driver
DSC
Decoder
DMA
Ctrl
MIPI DSI
MIPI DSI
Display
Controller
Display
Controller

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Use Case: 8K Digital TV
• TVs, STBs, and DVRs
• Multimedia SoC processor
• TCON (Timing Controller)
• Inside 8K TV
• Based on DSC 1.2a
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Ethernet
DISPLAY
8K @ 60Hz
TCON IC
Multimedia SoC
DDR
Controller
Audio
CPU
GPU
H.264/5
Video/Audio
Decoder
DTV
Tuner
I/F
eDP Tx
DSC
Encoder
Ethernet
I/F WIFI
I/F
eDP Rx
DSC
Decoder
RF
USB-Type C or
DisplayPort 1.4
Over USB-C Alt Mode
4x 10Gb/s lanes
S/PDIF
USB-C
TS
DeMUX
DP Rx
DSC
Decoder
SDRAMSDRAMSDRAM
HDMI HDMI

23. © 2017 MIPI Alliance, Inc.
Use Case: USB Type-C Laptop & Extended Display
• USB Type-C triple use
– Peripheral
– DisplayPort (Alt Mode)
– Power delivery
• Shared bandwidth
– Ex. Dual external monitors
USB Type-C DP 1.4 transport
– Storage
– Networking
• DSC usage saves bandwidth for
other external devices
(storage, networking)
DisplayPort Alt-Mode for USB Type-C
Image Source: Cadence

24. © 2017 MIPI Alliance, Inc.
Use Case: USB Type-C Laptop & Extended Display
• Laptop with
GPU
• Dual external
monitors
• USB Type-C
DisplayPort 1.4
transport Peripheral (Storage , etc)
Peripheral (Storage, etc)
Internal Display
CPU
GPU
DP Tx
DSC
Encoder
eDP Tx
USB-CEthernet
WIFI I/F
Display Driver
IC
eDP Rx
Display Driver
IC
SDRAMSDRAMSDRAM
DP Rx
DSC
Decoder
Display
4K @ 60Hz
External Monitor #1
USB/DP
I/F
USB
Hub
DDR Ctrl
Laptop
Single USB
Type-C
Connector
Display Driver
IC
DP Rx
DSC
Decoder
Display
4K @ 60Hz
External Monitor #2
Peripheral
(Storage, etc)
USB-C Peripheral
(Storage, etc)
USB-C

25. © 2017 MIPI Alliance, Inc.
How to Integrate VESA DSC in Your Next Design
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26. © 2017 MIPI Alliance, Inc.
VESA DSC Encoder and Decoder IP
DSC Encoder DSC Decoder

27. © 2017 MIPI Alliance, Inc.
How Are Images Processed by VESA DSC?
1 Vertical Slice2 Vertical Slices4 Vertical Slices

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Use Case: Two Vertical Slices
• Example: 4K video 60 fps
• ASIC with pixel clock at 350
MHz
• Each slice = 350 Mpixels / sec
• Two vertical slices are needed
• Number of slices need to
match between DSC Encoder
and Decoder
DSC Encoder DSC Decoder

29. © 2017 MIPI Alliance, Inc.
WQHD Mobile Application
1440 x 2560 x 60 fps 7 Gbps
AP
GPU
DPU

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WQUXGA VR Mobile Application
2400 x 3860 x 90 fps 24 Gbps
AP
GPU
DPU

31. © 2017 MIPI Alliance, Inc.
Conformance Test Guideline (CTG)
Uncompressed
Source Picture
Compressed
Picture
Reconstructed
Display PictureDSC Encoder DSC Decoder
CRC
Uncompressed
Source Picture
CRC
Compressed
Picture
CRC
Reconstructed
Pixel Stream

32. © 2017 MIPI Alliance, Inc.
FPGA Prototyping

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More Information
• VESA DSC white paper
– www.vesa.org/wp-content/uploads/2014/04/VESA_DSC-ETP200.pdf
• VESA DSC standard overview
– www.vesa.org/vesa-standards
• VESA membership
– www.vesa.org/join-vesamemberships
• A Quick Guide To VESA DSC
– www.hardent.com/vesa-display-stream-compression-guide
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34. © 2017 MIPI Alliance, Inc.
Live Demo of VESA DSC
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• Visit Hardent in the exhibitor area to see a live 4K demo of
VESA DSC!