1. A method for encoding a stream of K-bit input sequences into a stream of (G, I, M)-constrained 2N-bit output sequences, comprising: transforming each K-bit input bit sequence into two separate data paths including even and odd bits; enumerative maximum-transition-run (eMTR) encoding the even bits to generate constrained even bits; enumerative maximum-transition-run (eMTR) encoding the odd bits to generate constrained odd bits; and interleaving the constrained even and constrained odd bits to form a stream of (G, I, M)-constrained 2N-bit output sequences where G is a global constraint, I is an interleaved constraint, and M is a variable frequency oscillator constraint of a partial-response maximum-likelihood (PRML) code.