if !self.is_stereo || (fflags & 4) != 0 {
(self.decode_mono)(&mut coder, &mut self.left)?;
self.fmode.filter_mono(&mut self.left);
if !self.is_stereo || (fflags & 4) != 0 {
(self.decode_mono)(&mut coder, &mut self.left)?;
self.fmode.filter_mono(&mut self.left);