I don't have High Def tv or High Def directv yet, but I have had directv for years and they claim that I am receiving dolby digital 5.1 surround sound. I have noticed that the quality of the 5.1 from them is not as good as when I rent a standard dvd.
I recently purchased a headset that plays virtual 5.1 dolby surround sound. When I used it on my dvd player the indicator light on it for the source indicated I was receiving true dolby digital 5.1 surround sound to the head set base. When I hooked the base from the headset to the directv fiber optic surround sound output the headphone base indicated it was only dolby prologic 5.1 surround sound. It is only simulated, not true digital 5.1.
I called directv support and got a lot of stuttering and tripping over their tongues about it. I prefer to rent from a place that has dvds so I know what I am getting.
The last conversation with directv led me to be offered to upgrade to high def. They claim I will then get true 5.1 digital surround sound. I can only wonder if this is true or not. I also don't care for the idea that once you start playing a rental from directv you only have 24 hours before they delete or deactivate it from the dvr. You have a few days to keep it with blockbuster. You only have 24 hours with redbox but it only costs a dollar and I know it's true 5.1 digital surround sound from redbox.