This guide was most useful, thanks very much!
I've got an Auzentech X-Fi prelude and, using the new PAX drivers, I can successfully grab the DTS bitstream (requires bitmatched recording) and throw it through AC3filter in graphedit. Obviously, the latency was an issue, so I did exactly the above, but in AC3filter, I disabled the SPDIF-out stuff, including pass-through, so I'm getting playback on the PC itself.
However, I'm only getting the left and right channels from the decoded DTS input when using the "open device" method in MPC (there were no separate inputs, just the one for the whole card; the input is specified in the recording control).
This is especially confusing when, using graphedit to connect to the MPC graph and saving it, all the channels come through fine (just with that annoying delay). The AC3filter configuration shows up exactly the same in both cases, and shows "levels" for all six channels.
Is it something to do with MPC setting the number of channels, because it's "opened" a 2-ch source? How can I circumvent this? MPC plays DTS, AC3 files with the full complement of channels, so I cannot for the life of me figure it out.
Just two months ago I was thinking this would never be possible, but now that I can actually hear the DTS input, I'm very much impressed and encouraged - just miffed that there's still this one niggle!
Is there something obvious I'm missing, or is there any other way (i.e. with other software etc.) I can "play" the SPDIF input directly and avoid the latency? Thanks in advance!
XP32 SP3, Auzentech X-Fi Prelude (PAX Auzentech v3.10), AC3filter v1.63b, MPC v1.2.972.0
I was mistaken. The graph I saved from MPC does not work with all six channels. If I construct it manually, it still does not work. However, I noticed that when I load a dts / ac3 file into graphedit, the clock icon on the renderer (Default DirectSound Device, in all cases) is yellow after I press "play", but in the MPC graph (and by default) it is always plain. Right clicking the renderer and clicking "select clock" turns the clock icon yellow, and I get all six channels when I press play!
Below, the top graph works fine, with all six channels audible; the bottom one gives only Left and Right (but AC3 filter shows activity on all six channels). The only difference is that "select clock" is used in the top one.
So, the question is, how do I get MPC to use the "clock" when it opens the digital input? As far as I can tell, the clock is for synchronisation, so it's confusing that it makes a difference, to say the least!
In graphedit, the audio output is not only delayed, but it also phases slightly, i.e. by playing slightly too fast (48.6 kHz), before slowing down for a bit (~ 47.5 kHz), and then resuming at the faster rate. It does this no matter the "clock" setting.
I've had a stab with VLC, but I can't get it to open the input at all. So annoyingly close!