DirectX Video Acceleration Specification for Windows Media Video v8, v9 and vA Decoding (Including SMPTE 421M "VC-1") Gary J. Sullivan Microsoft Corporation December 2007, updated August 2010 and August 2012 Applies to: DirectX Video Acceleration Summary: Defines extensions to DirectX Video Acceleration (DXVA) to support decoding of Windows Media Video (WMV) 8, WMV 9, and SMPTE VC-1. The information contained in this document represents the current view of Microsoft Corporation on the issues discussed as of the date of publication. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information presented after the date of publication. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AS TO THE INFORMATION IN THIS DOCUMENT. Complying with all applicable copyright laws is the responsibility of the user. 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Contents Contents ................................................................................................................................... 3 1.0 Introduction ........................................................................................................................ 6 1.1 Document Conventions ................................................................................................. 7 Numbers ......................................................................................................................... 7 Function and Operator Definitions .................................................................................. 7 2.0 Overview of WMV 8 and WMV 9 ........................................................................................ 7 2.1 Sampling Structure ........................................................................................................ 7 2.2 Prediction Mode Indication and Motion Compensation ................................................. 7 2.2.1 WMV 8 Motion Compensation ............................................................................... 7 2.2.2 WMV 9 Prediction Mode ........................................................................................ 8 2.2.3 WMV 9 Motion Compensation ............................................................................... 8 2.2.3.1 Reference Picture Dynamic Range Adjustment ............................................... 8 2.2.3.2 Reference Picture Scaling and Offset Compensation ...................................... 9 2.2.3.3 Bi-Directional Prediction ................................................................................... 9 2.2.3.4 Two-Stage Quarter-Sample Motion Compensation with Rounding Control ..... 9 2.2.3.5 Four Motion Vectors per Macroblock ............................................................. 10 2.2.3.6 Advanced Profile 4:2:0 Interlace Support ....................................................... 10 2.3 Residual Difference Coding ......................................................................................... 10 2.4 Deblocking and Deringing Filters................................................................................. 11 2.4.1 WMV 8 In-Loop Deblocking Filter ........................................................................ 11 2.4.2 WMV 8 Out-of-Loop Deblocking Filter ................................................................. 11 2.4.3 WMV 8 Out-of-Loop Deringing Filter ................................................................... 11 2.4.4 WMV 9 In-Loop Blocking Filter ............................................................................ 11 2.4.5 WMV 9 Out-of-Loop Blocking Filter ..................................................................... 11 2.4.6 WMV 9 Out-of-Loop Deringing Filter ................................................................... 11 2.5 Uncompressed Surface Memory Requirements .......................................................... 12 2.5.1 Post-Processing Only .......................................................................................... 12 2.5.2 Motion Compensation with In-Loop and Out-of-Loop Filtering ............................ 12 2.5.2.1 Motion Compensation with In-Loop and Out-of-Loop Filtering for WMV 8 ..... 12 2.5.2.2 Motion Compensation with In-Loop and Out-of-Loop Filtering for WMV 9 ..... 12 2.6 WMV 9 Picture Upsampling ........................................................................................ 13 3.0 DXVA Data Structures and Operation .............................................................................. 13 3.1 Configuration Parameters ........................................................................................... 13 3.1.1 Degrees of Post-Processing Support .................................................................. 14 3.1.2 Alternative Configuration for Long-Term Reference Support ............................... 15 3.2 Picture Parameters Data Structure .............................................................................. 16 3.2.1 Picture Structure .................................................................................................. 16 3.2.2 WMV Use of bSecondField Member ................................................................... 16 3.2.3 Macroblock Width and Height .............................................................................. 17 3.2.4 Inverse-Scan Method .......................................................................................... 17 3.2.5 Flags Conveyed in bBidirectionalAveragingMode ............................................... 17 3.2.6 Picture Width and Height ..................................................................................... 17 3.2.7 Lack of Backward Prediction in WMV 8 ............................................................... 19 3.2.8 Backward Prediction in WMV 9 ........................................................................... 19 3.2.9 Motion Compensation Padding ............................................................................ 19 3.2.10 WMV 8 Half-Sample Motion Compensation ...................................................... 22 3.2.11 WMV 8 Quarter-Sample Motion Compensation ................................................. 22 3.2.11.1 WMV 8 Quarter-Sample Luma Motion Compensation ................................. 22 3.2.11.2 WMV 8 Quarter-Sample Chroma Motion Compensation.............................. 22 3.2.12 WMV 9 Bidirectional Prediction ......................................................................... 23 3.2.13 WMV 9 Four Motion Vectors per Macroblock (4-MV) ........................................ 23 DirectX Video Acceleration for Windows