VESA Display Stream Compression (DSC) Standard, Version 1

1 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 1 of 145 VESA Display Stream Compression (DSC) January, 2017 PurposeThe purpose of this document is to specify the VESA Display Stream Compression (DSC) DSC Standard is a specification of the algorithms used for compressing and decompressing image Display streams, including the specification of the syntax and semantics of the compressed video bitstream. DSC is designed for real-time systems, with real-time Compression , transmission, decompression, and specifies the compressed video bitstream. DSC does not specify a Transport Layer. Practical systems that use DSC must follow a suitable transport specification in which the Transport Layer conveys DSC streams, from source to is a Compression and decompression standard for Display streams between two distinct devices, either from one box level product to another, or from one chip to another within a box-level product, by way of a Display Stream interface.

2 Display Stream interfaces that could apply this standard include those between a mobile application host processor and Display panel module, between a computer graphics output and Display monitor, or between a consumer electronics source device to a Display device, such as a television. Display Stream interfaces can be either wired or Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 2 of 145 ContentsPurpose .. 1 Summary .. 1 Intellectual Property ..9 Trademarks ..9 Patents ..9 Support for this Standard..11 Acknowledgments ..11 Revision History ..13 Section 1 Introduction .. Organization .. Stream Compression Objectives.

3 Stream Compression Versions .. , Initialisms, and Abbreviations .. Ordering .. Documents ..23 Section 2 Requirements (Informative) .. 24 Section 3 Theory of Operation (Informative) .. Space Conversion.. and Quantization .. Median-Adaptive Prediction .. Prediction .. Prediction .. Color History .. Construction.. Layer .. Multiplexing .. Control .. Reference Decoder-Based Timing Model .. and Variable Bit Rate Modes .. and Timing .. for Slices .. Multiplexing ..46 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 3 of between DSC and DSC .. Native 4:2:2 and 4:2:0 Modes .. 14- and 16-bits Per Component Support.

4 Other Differences ..49 Section 4 Syntax (Normative) .. Parameter Set .. Parameter Set Timing .. Syntax .. Syntax Overview.. Multiplexing in Constant Bit Rate Mode .. Multiplexing in Variable Bit Rate Mode .. Multiplexing .. Syntax ..65 Section 5 Capability Parameter Set (Informative) .. 73 Section 6 Encoding Process (Normative) .. Space Conversion.. Padding .. Storage .. and Quantization .. Median-Adaptive Prediction .. Prediction .. Prediction .. Method Decision .. Quantization and Reconstruction .. Color History .. History .. Color History Updates.. Decisions.. Encoder.. Size Unit-Variable Length Coding .. Color History Coding .. Signaling .. to Rate Control .. Multiplexer .. FIFOs.. Model .. of Slice ..96 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association.

5 All rights reserved. Page 4 of Control Algorithm .. Level Tracker.. Transformation .. Parameter Selection.. Quantization Parameter Adjustment .. Quantization Parameter Overrides .. QP to qLevel..113 Section 7 Decoding Process (Normative) .. Demultiplexing .. Decoding .. Control .. Storage .. and Reconstruction .. Methods .. Method Selection .. Color History .. History Updates .. Space Conversion.. Handling ..121 Annex A DSC File Format (Normative) .. 122 Annex B Simple 4:2:2 Mode (Informative) .. 123 Annex C Guidance for Mapping to Transport (Informative) .. 125 Annex D Guidance for Hardware Implementations (Informative) .. Prediction .. Buffer Size ..128 Annex E Derivation of Rate Control Parameters (Informative) .. 129 Annex F Hypothetical Reference Decoder (Informative).

6 134 Annex G Slice Timing Examples (Informative) .. Statement .. 1 Slice/Line .. 2 Slices/Line .. 4 Slices/Line ..142 Annex H Main Contributor History (Previous Versions).. 144 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 5 of 145 TablesTable 1:Patents ..9 Table 2:Main Contributors to DSC ..11 Table 3:Revision History ..13 Table 1-1:DSC Supported Modes, by Version ..17 Table 1-2:Acronyms, Initialisms, and Abbreviations ..17 Table 1-3:Glossary of Terms ..19 Table 1-4:Normative Reference Document ..23 Table 1-5:Informative Reference Documents ..23 Table 3-1:Examples of Sizes for Different Residual ValuesUsed in Delta Size Unit-Variable Length Coding.

7 34 Table 3-2:Rate Control Components ..38 Table 4-1:Picture Parameter Set Syntax Elements ..50 Table 4-2:rc_parameter_set Field Descriptions ..57 Table 4-3:rc_range_parameters Field Descriptions ..58 Table 4-4:Picture Layer Syntax (Constant Bit Rate Mode) ..59 Table 4-5:Picture Layer Syntax (Variable Bit Rate Mode) ..61 Table 4-6:Slice Layer Syntax when native_422 = 0 ..64 Table 4-7:Slice Layer Syntax Field Descriptions ..64 Table 4-8:Y Substream Layer Syntax ..65 Table 4-9:Y_syntax_element() Syntax ..65 Table 4-10:Y_syntax_element() Descriptions ..67 Table 4-11:Y2 Substream Layer Syntax (Native 4:2:2 Mode Only) ..67 Table 4-12:Y2_syntax_element() Syntax (Native 4:2:2 Mode Only)..68 Table 4-13:Y2_syntax_element() Descriptions ..68 Table 4-14:Co Substream Layer Syntax.

8 69 Table 4-15:Co_syntax_element() Syntax ..69 Table 4-16:Co_syntax_element() Descriptions ..70 Table 4-17:Cg Substream Layer Syntax ..71 Table 4-18:Cg_syntax_element() Syntax ..71 Table 4-19:Cg_syntax_element() Descriptions ..72 Table 5-1:Recommended Capability Parameter Set ..73 Table 6-1:Prefix Codebooks Summary ..93 Table 6-2:Mapping of QP to qLevel ..114 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 6 of 145 Table A-1:.DSC File Format..122 Table E-1:Useful Intermediate Rate Control Parameter Values ..129 Table E-2:Recommended and Required PPS Syntax Element Rate Control Values ..130 Table E-3:Recommended Alternative Slice Dimensions to Prevent scale_increment_interval.

9 131 Table E-4:rc_parameter_set Syntax Elements Typically Constant across Operating Modes ..131 Table E-5:Common Recommended Rate Control-Related Parameter Values..132 Table H-1:Main Contributor History (Previous Versions) ..144 VESA Display Stream Compression (DSC) StandardUNAUTHORIZED DISTRIBUTION PROHIBITED Version 2014 2017 Video Electronics Standards Association. All rights reserved. Page 7 of 145 FiguresFigure 3-1:DSC Use in End-to-end System ..25 Figure 3-2:DSC Syntax and Application Layer Hierarchy ..26 Figure 3-3:Relationship between Picture Parameter Set, Pictures, and Slices ..27 Figure 3-4:Encoding Process..28 Figure 3-5:Decoding Process ..29 Figure 3-6:Example of Samples Used for Block Point Search and Prediction for BP Vector = -10.

10 32 Figure 3-7:Indexed Color History Concept..33 Figure 3-8:Example of Slice Layer Multiplexing Output ..36 Figure 3-9:Example of Substream Demultiplexing..36 Figure 3-10:Example of Substream Multiplexing..37 Figure 3-11:Decoder Slice Timing and Delays for Two Slices/Line ..46 Figure 3-12:Sample Positions in a Group for Native 4:2:2 Mode ..47 Figure 3-13:Mapping of 4:2:2/4:2:0 Picture to 4:4:4:4/4:4:4 Container ..48 Figure 3-14:Sample Positions in a Group for Native 4:2:0 Mode (Even- and Odd-position Lines) ..49 Figure 6-1:Pixels Surrounding Current Group ..76 Figure 6-2:Pixel Positions Used for Luma MMAP in Native 4:2:2 and 4:2:0 Modes ..78 Figure 6-3:Pixel Positions Used for Chroma MMAP in Native 4:2:2 Mode ..78 Figure 6-4:Pixel Positions Used for Chroma MMAP in Native 4:2:0 Mode.