code: func (h FrameHeader) Samples() int {
  	if len(h) < 4 {
  		return 0
  	}
  	ftype, ok := samplesPerFrame[h.Version()]
  	if !ok {
  		return 0
  	}
  	return ftype[h.Layer()]
  }
docs: // Samples is the number of samples contained in this frame