MPEG1_A

The MPEG1_A restricted profile contains a set of features required for support of MPEG-1 video. Support of this profile is required for video accelerator drivers that provide hardware video acceleration capabilities. This set of features is defined by the following set 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_MPEG1_A

Restrictions on DXVA_PictureParameters

Structure Member	Value
BPP variable (defined by adding 1 to bBPPminus1)	Equals 8
bSecondField	Equals zero
MacroblockWidthMinus1	15
MacroblockHeightMinus1	15
bBlockWidthMinus1	7
bBlockHeightMinus1	7
bChromaFormat (4:2:0)	1
bPicStructure	3 (frame structured)
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	Zero

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
MotionType	2 (frame motion)
MBscanMethod	Zero (zigzag) if bConfigHostInverseScan equals zero
FieldResidual	Zero (frame residual)
H261LoopFilter	Zero (no H.261 loop filter)

Restrictions on Bitstream Buffers

The contents of any bitstream buffer must contain data in the MPEG-1 main profile video format.