Help me understand!

My adventures with ripping bluray continues, and I get more confused by the day.  I’ve done about 2 rips now, and I’ve been using VLC to play them back.  But tonight I tried Media Player Classic, and I’m confused by what I “heard”.

My first rip was Hellboy 2; it’s an mp4 with 5.1 AAC audio (at 192 kbps).  The second rip was Open Season 2; it’s an mkv and I chose “Copy STREAM” in RipBot so I assumed that meant it copied the original audio (which is Dolby TrueHD).  I tried playing in SageTV, and this is the first part that I found curious.  The video plays, but I found it strange that audio plays as well but I have to put the receiver on 6 channel Input.  The reason I find it strange is because, if you remember, I use 2 sound cards, and I have SageTV set to use the Envy 24 as the audio renderer so I can use SPDIF as the output; this is not the default card of the system though.  So somehow, SageTV is using a different renderer than what I’ve specified.  This isn’t necessarily a bad thing, but the sound is like 6 channel stereo.  It’s not discrete 6 channels.  AC3 Filter is set as the audio decoder, but it is set for SPDIF.

So, since the sound is not to my liking I started using VLC.  With it I get a great video, discrete 6 channel audio through the analog inputs on my receiver, but I have no control with the remote.  Also, the Open Season 2 audio did not sound very good.  I compared it to the original bluray, and I thought the bluray’s audio was much clearer and more “defined”.  The bass was quite pitiful in VLC.  But I wonder if it was just my imagination.  I mean, if “Copy STREAM” is not copying the original audio in RipBot, then what the heck is it?

Tonight I decided to try Media Player Classic to see if there was a difference.  When it started playing, I immediately thought the audio was better than VLC, but then I noticed my receiver was lit up as Dolby Digital.  I forgot to change the receiver to the analog ins, but I had sound any way.  So this confuses me on several fronts.  First, MPC is using the Envy 24 sound card so it’s not using the system default onboard audio; this is the opposite of what SageTV is doing.  Second, none of the other players will play the sound through SPDIF, but MPC for some reason will.  Third, if the audio is the original stream of the bluray, then how is sound coming from SPDIF?  Fourth, I THOUGHT that MPC was using AC3 Filter as the audio decoder; but if that’s true then why doesn’t SageTV and MPC behave in the same way?

If any one can explain any of this, then you know way too much, LOL.