fn decode_frame(&mut self, br: &mut ByteReader) -> DecoderResult<bool> {
let frame_x = br.read_u16le()? as usize;
let frame_y = br.read_u16le()? as usize;
fn decode_frame(&mut self, br: &mut ByteReader) -> DecoderResult<bool> {
let frame_x = br.read_u16le()? as usize;
let frame_y = br.read_u16le()? as usize;