Convert RGB surface to YUV in hardware using Direct3D 9 - c++

Question

I have an ARGB Direct3D9 surface that I need to blit into UYVY surface of the same dimensions. Both surfaces are in system memory. How can I accomplish this?
UpdateSurface and StretchRect fail.
I'm open to using textures instead of surfaces if needed.
This must be done in GPU, i.e. with hardware acceleration.

Answer 1

In DirectXTex there is code for doing all these conversions you could look at for reference. The legacy Direct3D 9 D3DFMT_UYVY format is the same as DXGI_FORMAT_YUY2 with some channel swizzling.
These formats encode two visible pixels in each image pixel:
struct XMUBYTEN4 { // DirectXMath data type
uint8_t x;
uint8_t y;
uint8_t z;
uint8_t w;
};
XMUBYTEN4 rgb1, rgb2 = // Input pixel pair
int y0 = ((66 * rgb1.x + 129 * rgb1.y + 25 * rgb1.z + 128) >> 8) + 16;
int u0 = ((-38 * rgb1.x - 74 * rgb1.y + 112 * rgb1.z + 128) >> 8) + 128;
int v0 = ((112 * rgb1.x - 94 * rgb1.y - 18 * rgb1.z + 128) >> 8) + 128;
int y1 = ((66 * rgb2.x + 129 * rgb2.y + 25 * rgb2.z + 128) >> 8) + 16;
int u1 = ((-38 * rgb2.x - 74 * rgb2.y + 112 * rgb2.z + 128) >> 8) + 128;
int v1 = ((112 * rgb2.x - 94 * rgb2.y - 18 * rgb2.z + 128) >> 8) + 128;
For DXGI_FORMAT_YUY2 you would use:
XMUBYTEN4 *dPtr = // Output pixel pair
dPtr->x = static_cast<uint8_t>(std::min<int>(std::max<int>(y0, 0), 255));
dPtr->y = static_cast<uint8_t>(std::min<int>(std::max<int>((u0 + u1) >> 1, 0), 255));
dPtr->z = static_cast<uint8_t>(std::min<int>(std::max<int>(y1, 0), 255));
dPtr->w = static_cast<uint8_t>(std::min<int>(std::max<int>((v0 + v1) >> 1, 0), 255));
For D3DFMT_UYVY you would use:
dPtr->x = static_cast<uint8_t>(std::min<int>(std::max<int>((u0 + u1) >> 1, 0), 255));
dPtr->y = static_cast<uint8_t>(std::min<int>(std::max<int>(y0, 0), 255));
dPtr->z = static_cast<uint8_t>(std::min<int>(std::max<int>((v0 + v1) >> 1, 0), 255));
dPtr->w = static_cast<uint8_t>(std::min<int>(std::max<int>(y1, 0), 255));