MPEG2_A
The MPEG2_A restricted profile contains a set of features required for support of MPEG-2 video Main Profile. Support of this profile is required for video accelerator drivers that provide hardware video acceleration capabilities.
The MPEG2_A profile is defined by the following sets of restrictions:
Restrictions on DXVA_ConnectMode
The following restriction on the DXVA_ConnectMode structure applies when the bDXVA_Func variable defined in the dwFunction member of the DXVA_ConfigPictureDecode structure is equal to 1.
| Structure Member | Value |
|---|---|
wRestrictedMode |
DXVA_RESTRICTED_MODE_MPEG2_A |
Restrictions on DXVA_PictureParameters
| Structure Member | Value |
|---|---|
wRestrictedMode |
0x0A |
BPP variable (defined by adding 1 to bBPPminus1) |
8 |
MacroblockWidthMinus1 |
15 |
MacroblockHeightMinus1 |
15 |
bBlockWidthMinus1 |
7 |
bBlockHeightMinus1 |
7 |
bChromaFormat (4:2:0) |
1 |
bRcontrol |
Zero |
bBidirectionalAveragingMode |
Zero (MPEG-2 bidirectional averaging) |
bMVprecisionAndChromaRelation |
Zero (MPEG-2 half-sample motion) |
bPicExtrapolation |
Zero |
bPicDeblocked |
Zero |
bPic4MVallowed |
Zero |
bPicOBMC |
Zero |
bMV_RPS |
Zero |
SpecificIDCT |
Zero |
bPicScanFixed |
1 |
Restrictions on DXVA_MBctrl_I_HostResidDiff_1, DXVA_MBctrl_I_OffHostIDCT_1, DXVA_MBctrl_P_HostResidDiff_1, and DXVA_MBctrl_P_OffHostIDCT_1
| wMBtype Bits | Value |
|---|---|
MBscanMethod |
May be a value of zero (zigzag) or a value of 1 (alternate vertical) if the ConfigHostInverseScan member of DXVA_ConfigPictureDecode is equal to zero. |
H261LoopFilter |
Zero |
Restrictions on Bitstream Buffers
The contents of any bitstream buffer must contain data in the MPEG-2 main profile video format.
The bNewQmatrix member of DXVA_QmatrixData equals zero, for i = 2 and 3 when inverse-quantization matrices are used.