sampleRate := 48000
channelCount := 2

faacEncoder := faac.Open(sampleRate, channelCount)
config := faac.EncoderConfiguration{
	BitRate:     48000,
	InputFormat: faac.InputFloat,
}

err := faacEncoder.SetConfiguration(&config)
if err != nil {
   // ...
}

encodedBytes = faacEncoder.OutputBuffer()
var interleavedFloats = []float

// fill interleavedFloats for floats between +/- 32768.0
// len(interleavedFloats) must be (less than) faacEncoder.InputSamples()
// ...

encodedByteCount := faacEncoder.EncodeFloats(
	interleavedFloats,
	encodedBytes)

if encodedByteCount > 0 {
	writer.write encoder.encodedBytes[0:encodedByteCount]
}

faacEncoder.Close()