Can you suggest a few video players ? And what type is shown to work ? For example, for me AC-3 is good enough for me now but i will probably upgrade to Dolby True Hd 7.1 someday.

And also, i was thinkering a bit. Can hook up interface to AV receiver (probably not ) to stream True HD with adat. I suppose AV receivers only receiver SPDIF (with AC3)   but it is worth asking

Thanks

I can watch Quicktime movies with Dolby surround 5.1 on my Mac and FF UC.
I think this option is relatively new.
The mac seems to decode the material.
But I have to connect 6 active speakers to do so.
It does not work with EyeTV dolby 5.1 and DVD Player Dolby tracks.
You have to connect a receiver with HDMI or SPDF for this.
If not,
this will be put out as stereo on RME hardware.
I also tried to open an EyeTV stream with VLC and VLC can decode Dolby to 6 channels for RME on the fly.

Recordings from EyeTV and than converted by Handbrake with 5.1 Dolby , or AAC 5.1 can be watched with Quicktime.
For MKV movies with DBX 5.1 , I use VLC

Did you check the Speaker assignment to all channels in Audio MIDI Setup?