I have an HTPC connected to my receiver via HDMI.
My receiver has two HDMI outputs, one to my projector, the other to the TV.
When watching a movie on my projector, I use the receiver to process and amplify the audio.
Because my TV is at a 90* angle to the projector, I'm not using my HT speakers for the audio. If I'm watching a movie on the TV, I'm usually doing something else at my desk using the movie as background entertainment. In fact, I have the receiver off when I watch the TV (Standby power for the HDMI switching in the receiver).
Hopefully that's clear so far.
When I watch the projector, the receiver decodes and amplifies the audio. When watching the TV, the receiver ignores the audio and sends it to the TV for decoding and amplification through the built in speakers.
Because most of my movie rips are MKVs with DTS or DTS-HD MA audio, the TV obviously doesn't have a decoder for this and as such I get no sound.
The HTPC doesn't know what is decoding the sound, just that it bitstreams the audio and "something else" decodes it. What's the best way to set it up so I can switch to having the HTPC decoding it, downmix to 2ch and send it out in a format friendly for the TV?
Hope that's clear enough.