The VESA Display Stream Compression (DSC) standard is a visually lossless video compression algorithm that decreases transmission bandwidth by up to 3X, while lowering power and reducing EMI. The standard has been adopted by leading suppliers of semiconductors for use in mobiles, tablets, in-car video, and DTV applications in order to achieve higher resolution displays. This presentation by Hardent's Alain Legault provides background information about DSC and the role it plays in today’s interface IP ecosystem when combined with MIPI® DSI, USB Type-C™, DisplayPort™ and Embedded DisplayPort™, and HDMI™ IPs. Several use cases are discussed, and practical information on how to successfully integrate DSC in semiconductor designs is also provided.

1. VESA
Display Stream
Compression (DSC)
How to Use the VESA Display Stream
Compression (DSC) Standard to Create
Higher Resolution Displays for
Consumer Electronics Applications
Alain Legault, Hardent, Inc.

2. Agenda
• What Is DSC?
• DSC in Consumer Electronics Applications
• How To Integrate DSC In Your Next Semiconductor
Design

3. PART 1:
WHAT IS DSC?

4. Why Is DSC Needed?
Mobile applica+on processor MIPI DSI DDIC
Computer GPU card DisplayPort cable Computer monitor
Car applica+on processor Proprietary transport Car infotainment display
Processor TX
Port
Display
Module
RX
Port
To Display Video In

5. 2011 2012 2013 2014 2015 2016
WXGA HD FHD QHD UHD 5K
Mind the Gap
PHY trend +20%/year
PHY per Lane Gb/s
Display resolution
CAGR >2x / year
MPixels
1.0
2.0
3.0
4.0
5.0
Source: Dale Stolitzka & David Hoffman
Samsung Display Company
1
4
4
4
1
2
1
0
8
6
4
2
0

6. Compression Power & Area Trade-off
SWEET SPOT
2x – 3x compression
Source: Dale Stolitzka & David Hoffman
Samsung Display Company

7. Increase In Available Bandwidth
Time PHY
Speed
Bit Coding
(8b/10b ! 128b/
132b)
Image
Coding
Link
Speed
T = 0 1x 1x 1x 1x
T + 2 years 1.44x 1,23x 2x – 3x 3.5 – 5x
PHY
Bit
Coding
(if applicable)
Image
Coding
Pixel
Data
Link
Payload

8. PHY Speed / Display Resolution
ResoluYon
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
D-PHY v1.1 1.5 Gbps / lane
ResoluYon
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
D-PHY v1.2 2.5 Gbps / lane

9. DSI Link Compression
TX
Port
RX
Port
To Display
Processor
GPU
DSC
Encoder
DSC
Decoder
Display
Module
Frame
Buffer
Video In

10. VESA DSC Task Group - 2013

11. VESA DSC Task Group: Work Completed
• Call for proposals in the industry
• Six proposals were presented
• Selection committee
• Reviewed proposals
• Conducted video quality tests using various types of content (images,
text, and graphics)
• Broadcom BDC algorithm was chosen
• Liaison committee with the MIPI Alliance
• Several image quality test iterations and algorithmic
improvements
• DSC C-model golden reference code
• Version 31 was released

12. VESA DSC Standard
January 2013
DSC Task Group
Formed
April 2014
DSC
Announced
July 2014
DSC v1.1
Released
January
2016
DSC v1.2
Released

13. VESA DSC Task Group - 2016

14. Overview of DSC Algorithm

15. Overview of 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
• Visually lossless compression between 2X – 3X
• Video quality excellent with all types of content
• Natural and test images, text and graphics

16. Subjective Testing Evaluates Image Quality
ISO/IEC IS 29170-2 test method
Ref
Test
Ref
Test
Ref
Test
Ref
vs. 5Hz
Source: Dale Stolitzka & David Hoffman
Samsung Display Company

17. Objective Metrics Do Not Predict
Performance
Mean response fractionMean response fraction
log10(HDRVDP2)
PSNR
PSNR = peak signal to noise ratio
HDR VDP2 = high dynamic range visual difference predictor #2
Visually lossless
Barely perceptible
Impaired
Source: Dale Stolitzka & David Hoffman
Samsung Display Company

18. Subjective Testing Guidelines
E = 30 pixels/degree (PPD)5⁰
Source: Dale Stolitzka & David Hoffman
Samsung Display Company
ISO/IEC IS 29170-2
Display
Conditions
ISO 3664, ISO 9241-303
Monitor Calibrated monitor
Color sRGB, BT.709, BT.2010
Viewing
Distance
Distance at 30 PPD
EvaluaYon procedure for nearly lossless coding
Image
Viewing
1:1 side/side or interleaved
Image
Sets
Wide set of images, graphics, text
and engineered images
Video
Sets
SVT fairytale and game screen
captures
ISO/IEC IS 29170-2 Evalua+on procedure for nearly lossless coding

19. Why Adopt DSC?

20. DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
ApplicaYon
Processor
MIPI DSI
Tx
MIPI DSI
Rx
MIPI DSI
Rx
DSC
Decoder
SDRAM
Display Driver
IC
Frame Buffer
SDRAM SDRAM

21. DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
ApplicaYon
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

22. DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
ApplicaYon
Processor
MIPI DSI
Tx
MIPI DSI
Rx
MIPI DSI
Rx
DSC
Decoder
SDRAM
Display Driver
IC
Frame Buffer
SDRAM
Remove
SDRAMs SDRAM

23. DSC Helps Save Power, Area, and Cost
MIPI DSI
Transport Lanes
DSC
Encoder
MIPI DSI
Tx
ApplicaYon
Processor MIPI DSI
Rx
DSC
Decoder
Display Driver
IC
Frame Buffer
SDRAM
Less power
Smaller footprint
Lower cost

24. Transport Standards Using DSC
MIPI® DSI 1.2
eDisplayPort™ 1.4b
DisplayPort™ 1.4

25. DSC Standard Availability and Support
Source: VESA

26. Products Using DSC
Qualcomm Snapdragon 820 NVIDIA Tegra X1

27. PART 2:
DSC IN CONSUMER
ELECTRONICS APPLICATIONS

28. DSC Decoder
Display
Driver IC
MIPI DSI
Transport
Lanes
ApplicaYon
Processor
MIPI DSI and
D-PHY
MIPI DSI and
D-PHY
DSC Encoder
GPU
Use Case: Mobile and Tablet Applications
• Application processor
• DDIC (Display Driver IC) and touch
panel controller
High-DefiniYon
Display
Source: MIPI Alliance

29. 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
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
I3C
IP
Encap
Enet
I/F
SENSOR
Camera I /F
MIPI
CSI
Enet
I/F
IP
Encap
ISP
DSC
Enc
CAMERA

30. Use Case: AR / VR Head-Mounted Display
• Video capture
• Application
processor and
GPU
• Micro-display
driver IC
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

31. Use Case: USB Type-C Laptop & Extended
Display (1)
• 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

32. Use Case: USB Type-C Laptop & Extended
Display (2)
• 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

33. Use Case: Professional Video Transport
• Compression of UHD signals
allows transport over inexpensive
Ethernet links
• Ex. UHD (14.33Gbps) over
10GE with 2:1 compression
Encoder System
DSC
Encoder
Video
Interface
IP
Encapsulation
Video Input
Uncompressed Video
Ethermet
I/F
Video Ouput
Uncompressed Video
Decoder System
DSC
Decoder
Video
Interface
IP
Decapsulation
Ethermet
I/F

34. Use Case: 8K Digital TV
• TVs, STBs, and DVRs
• Multimedia SoC
processor
• TCON (Timing controller)
• Inside 8K TV
• Based on DSC 1.2
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

35. PART 3:
HOW TO INTEGRATE DSC IN YOUR
NEXT SEMICONDUCTOR DESIGN

36. DSC Encoder and Decoder IP
DSC Encoder DSC Decoder

37. How Are Images Processed by DSC?
1 VerYcal Slice 2 VerYcal Slices 4 VerYcal Slices

38. 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

39. Single DSC – Single DSI Stream Solution
1600 x 2560 x 60 fps 7 Gbps

40. Dual DSC – Dual DSI Stream Solution
2400 x 3860 x 60 fps 16 Gbps

41. Conformance Test Guideline (CTG)
Uncompressed
Source Picture
Compressed
Picture
Reconstructed
Display Picture
DSC Encoder DSC Decoder
CRC
Uncompressed
Source Picture
CRC
Compressed
Picture
CRC
Reconstructed
Pixel Stream

42. FPGA Prototyping

43. Further Reading
• DSC white paper
• http://www.vesa.org/wp-content/uploads/2014/04/VESA_DSC-
ETP200.pdf
• DSC standard
• http://www.vesa.org/vesa-standards/
• VESA membership
• http://www.vesa.org/join-vesamemberships/

44. Alain Legault
Hardent Inc.
alegault@hardent.com
www.hardent.com