Originally Posted by axell
I'm not a software engineer, so i have no clue about all those, but have a look at the comercial BD-players, have a alook at Syabas with their PCH - bitstreaming doesn't look so complicate right? I know i'm missing a lot of things here, but...
That would be because hardware players are not FORCED to implement PAP. They can simply read the stream off the disc and send it on down the HDMI pipeline right to the receiver.
Software players, however, have a unique set of requirements above and beyond stand alone players. These requirements aren't optional and in order to be a licensed player, they MUST be implemented. A software player needs to be able to read the data off the disc, as well, and must implement the same BD+, BD-J, AACS, etc code that a stand alone player needs to be able to do. However, they also have to protect the player process in memory to prevent syphoning of player/disc decryption keys, the BD+ implementation, and BD-J runtime. Now, to bitstream, they are REQUIRED to read the data from the disc, run through the AACS decryption process, and THEN they are required to RE-encrypt the audio stream using PAP to protect it while it runs through the PC bus to the audio device that's going to eventually send it to the receiver. The audio devices takes the re-encrypted audio stream, decrypts it internally, and is then allowed to bitstream it to the receiver. Is this a sick joke? Yes, yes it is. But, it's unfortunately the requirement that all licensed players have to follow. The trick to PAP is that each piece of hardware implementing it has its own way of encrypting and decrypting the audio stream. This would be why each new audio device that supports PAP must be specifically coded for in the player software. No standard API to follow there, making it far more complicated than it needs to be.
All this adds up to make the PC a nightmare where a stand alone has no such restrictions.
Edit: Sorry just saw you deleted your post but nonetheless I'll leave this here so others can understand why it's such a pain on the PC.