I know because when I toggle the audio button the info screen from my xa2 displays the audio output format. It goes between DD+ and Dolby True HD. And the True HD... well, all I can say for now is that it has more presence. I sense more detail, more enveloped sound. As soon as it goes off, things just seem a little more separate. DD+ is still really, really, good. HD almost has an intangible.
Oh well, no raw bitstream for now. But right now, I'm hearing the finest audio available even thought it is a PCM stream. So that is a fine reason for having my 1.3 dvd player. This is audioholics after all. Isn't it?