Function channel_count 

pub fn channel_count(acmod: u8, lfeon: bool) -> u16

Channel count derived from acmod + lfeon per ETSI TS 102 366 Table F.4. 1+1 dual-mono (acmod==0) gets two distinct mono streams (count=2). All other modes follow the conventional layout: 1.0 / 2.0 / 3.0 / 2.1 / 3.1 / 2.2 / 3.2 plus an optional LFE.