vDSP_DCT_Type.IV
A constant that specifies a type IV discrete cosine transform.
Declaration
case IVDiscussion
The type-IV DCT uses the following operation for a discrete cosine transform:
// `N` is the length given in the setup.
// `h` is the input array that contains real numbers.
// `H` is the output array that contains real numbers.
For 0 <= k < N
Or[k] = sum(Ir[j] * cos((k+1/2) * (j+1/2) * pi / N, 0 <= j < N)