apply_lpc(&mut cur_buf[32..][..32], &prev_buf[128 + 32..], &mut self.lpc_hist, &f1);
apply_lpc(&mut cur_buf[64..][..32], &prev_buf[128 + 64..], &mut self.lpc_hist, &f2);
apply_lpc(&mut cur_buf[32..][..32], &prev_buf[128 + 32..], &mut self.lpc_hist, &f1);
apply_lpc(&mut cur_buf[64..][..32], &prev_buf[128 + 64..], &mut self.lpc_hist, &f2);