code: func (h FrameHeader) SampleRate() FrameSampleRate {
  	if len(h) < 4 {
  		return 0
  	}
  	sri := (h[2] >> 2) & 0x03
  	if sri == 0x03 {
  		return ErrInvalidSampleRate
  	}
  	return FrameSampleRate(sampleRates[h.Version()][sri])
  }
docs: // SampleRate returns the samplerate from the header