H261_A
The H261_A restricted profile contains the set of features required for minimal support of ITU-T Rec. H.261 without acceleration support for H.261 Annex D graphics. Support of this profile is currently encouraged, but not required. This set of features is defined by the following restrictions.
Restrictions on DXVA_ConnectMode
The following restriction on the DXVA_ConnectMode structure applies when the bDXVA_Func variable defined by the dwFunction member of the DXVA_ConfigPictureDecode structure is equal to 1 (picture decoding).
| Structure Member | Constant |
|---|---|
wRestrictedMode |
DXVA_RESTRICTED_MODE_H261_A |
Restrictions on DXVA_PictureParameters
The following restrictions on the DXVA_PictureParameters structure apply when the bDXVA_Func variable defined by the dwFunction member of DXVA_ConfigPictureDecode is equal to 1.
| Structure Member | Value |
|---|---|
bBPPMinus1 |
7 |
bSecondField |
Zero |
bMacroblockWidthMinus1 |
15 |
bMacroblockHeightMinus1 |
15 |
bBlockWidthMinus1 |
7 |
bBlockHeightMinus1 |
7 |
bChromaFormat |
1 (4:2:0) |
bPicStructure |
3 (frame structured) |
bMVprecisionAndChromaRelation |
2 (H.261 integer-sample motion) |
bPicExtrapolation |
Zero |
bPicDeblocked |
Zero |
bPic4MVallowed |
Zero |
bPicOBMC |
Zero |
bMV_RPS |
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
The following restrictions on the DXVA_MBctrl_I_HostResidDiff_1, DXVA_MBctrl_I_OffHostIDCT_1, DXVA_MBctrl_P_HostResidDiff_1, and DXVA_MBctrl_P_OffHostIDCT_1 structures apply when the bDXVA_Func variable defined by the dwFunction member of DXVA_ConfigPictureDecode is equal to 1.
| Structure Member | Value |
|---|---|
MotionType |
2 (frame motion) if the MotionForward variable defined in the wMBtype member of these structures equals 1. |
MBscanMethod |
Zero (zigzag) if the bConfigHostInverseScan member of DXVA_ConfigPictureDecode equals zero. |
FieldResidual |
Zero (frame residual) |
MotionBackward |
Zero (no backward prediction) |
Restrictions on Bitstream Buffers
The contents of any bitstream buffer must contain data in the H.261 video format.
This restriction applies when the bDXVA_Func variable defined by the dwFunction member of DXVA_ConfigPictureDecode is equal to 1.