ID3D11VideoContext::DecoderBeginFrame

DX11 vtable[9] → HRESULT

ID3D11VideoContext::DecoderBeginFrame is a method of the COM interface ID3D11VideoContext in Direct3D 11. Its function pointer sits at vtable index 9 — the zero-based slot in that interface's virtual method table, counted from QueryInterface and including every entry inherited from a base interface. It takes 4 parameters (decoder, view, key_size, key) and returns HRESULT.

COM methods are reached through that table rather than by an exported name, so the slot index is what a wrapper, an interface hook or a disassembly listing has to resolve against. The parameter order and types below are the ones this interface declares.