InterpolateQPBilinear_VC1

pParams->pSrc

Pointer to the source (for the _C2R function, in the NV12 format)

pParams->srcStep

Distance in bytes between starts of the consecutive lines in the source block

pParams-> pDst

Pointer to the destination (for the _C2R function, in the NV12 format)

pParams ->dstStep

Distance in bytes between starts of the consecutive lines in the destination block

pParams->dx, pParams->dy

Fractional parts of the motion vector in 1/4 pel units (0, 1, 2, or 3)

pParams ->bitDepth

Not used by this function, should be equal to 0

pParams-> roundControl

Frame level rounding control value as described in section 8.3.7 of [SMPTE421M], should be equal to 0 or 1

pParams-> roiSize

Block size, should be

16x16:

• Progressive frames/ 1-MV Macroblocks/ luma blocks

• Interlace fields/ 1-MV Macroblocks/ luma blocks

8x8:

• Progressive frames/ 4-MV Macroblocks/ luma and chroma blocks

• Progressive frames/ 4-MV Macroblocks/ chroma blocks

• Interlace fields/ 4-MV Macroblocks/ chroma blocks

• Interlace fields/ 1-MV Macroblocks/ chroma blocks

• Interlace frames/ 1-MV Macroblocks/ chroma blocks

8x4:

• Interlace frames/ 2-MV Macroblocks/ chroma blocks

4x4:

• Interlace frames/ 4-MV Macroblocks/ chroma blocks.

For the _C2R function, this block size should be 8x8, 8x4, 4x4 for each U or V component (actually, the real size of a combined UV block is 16x8, 16x4, 8x4).