:raw:perlio:encoding(UTF-16LE):crlf
[download]

##</code><code>##

    :raw:perlio:encoding(UTF-16LE):crlf:utf8

##</code><code>##

$ hd Input.txt 
00000000  ff fe e4 00 62 00 63 00  0d 00 0a 00    |..ä.b.c.....|

##</code><code>##

#!/usr/bin/perl -w
use strict;
use Devel::Peek;

open my $input_fh,
    '<:raw:perlio:encoding(UTF-16):crlf', 'Input.txt';

my $line = <$input_fh>;
chomp $line;
Dump $line;

##</code><code>##

SV = PV(0x69ae70) at 0x605000
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  PV = 0x6778e0 "\303\244bc"\0
  CUR = 4
  LEN = 80

##</code><code>##

SV = PV(0x750cb8) at 0x777cc8
  REFCNT = 1
  FLAGS = (PADMY,POK,pPOK,UTF8)
  PV = 0x86a070 "\303\244bc"\0 [UTF8 "\x{e4}bc"]
  CUR = 4
  LEN = 80

##</code><code>##

open my $fh, '<:encoding(UTF-16LE)', ...