fn open(&mut self, strmgr: &mut StreamManager, seek_index: &mut SeekIndex) -> DemuxerResult<()> {
let riff = self.src.read_u32be()?;
let riff_size = self.src.read_u32le()? as usize;
fn open(&mut self, strmgr: &mut StreamManager, seek_index: &mut SeekIndex) -> DemuxerResult<()> {
let riff = self.src.read_u32be()?;
let riff_size = self.src.read_u32le()? as usize;