Zero-copy access to the header fields of packets formatted according to SMPTE 2022-1, also know as 'Pro MPEG FEC' or '1D/2D parity FEC'.
Note this does not implement FEC encoding or decoding, just the parsing of the packet header fields.
Header data format
syntax fec_header() {
SNBase low bits u16
Length Recovery u16
E u1
PT recovery u7
Mask u24
TS recovery u32
N u1
D u1
type u3
index u3
Offset u8
NA u8
SNBase ext bits u8
}