Dear Community,

I have a binary of float32 representing audio data with floats in the range of [-1,1].
I want this audio data converted into a binary of signed 16 bit integers.
What is an efficient way of doing this in elexir? I tried:

  def to_linear16(<<>>) do
    <<>>
  end

  def to_linear16(<<v::float-size(32), r::binary>>) do
    Logger.debug("#{inspect(v)}")
    f =
      if v < 0 do
        <<trunc(v * 0x8000)::size(16)>>
      else
        <<trunc(v * 0x7FFF)::size(16)>>
      end

    f <> to_linear16(r)
  end

But there is something wrong:

• I get an no function clause matching in to_linear16/1 also I am only giving it data, that is definitly multples of 4 bytes long.
• I check the intermediate results via logging of the float32 extracted form the binary and they are not what I expect. In fact, if I put the same binary into Nx.from_tensor(b,:f32) I get different results.

So I am very puzzled here.

• What is an efficient way of doing this in elixir or am I already on the right track here?
• What am I doing wrong in the pattern matching? I am always taking a 32bit float from the beginning of the binary.So how could the matching fail?

Thank you!