yes it is funny..two things i noticed; When i play my x360, sometimes dolby digital does not turn on by itself, nor can i find it in the presets.
When i restart, and most of the time anyways, it automatically does switch to dd.
2.When i play hd content on tv, same thing happens sometimes, but here in the tv's menu i can easily switch to dd. When same video i play on my laptop-hdmi-avr, using (vlc) it also does not show dd, but in options-audio-audio channel, the 5.1 option becomes available and i can switch to it again, easily.
Funny business. Is best if the info in the bdrip before downloading gave us the audio track encoded. Sadly, most of them dont (i checked several today)