The Xaudio decoder is, as with almost all decoders, +- 0.5 bit (ie, the lowest bit of the output can differ from that of the frauhofer reference decoder).

This is pretty common with decoders due to optimisations and rounding - eg, winamp, etc all have the same limitations.

We wouldn't be happy shipping anything which had substandard decoding. We may well be switching to a more efficient decoder in the near future, and that also has the same accuracy.

Hugo