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[macdonjh]

I've been reading forums about getting a Mac to properly play multi-channel movie files, but all the threads are old and talk about cable adapters and patches.  What is the current method for playing multi-channel movies with MC21 for OS-X?

[blgentry]

I haven't used HDMI with MC for Mac yet.  But it should work like the windows version.  By default, MC is going to decode any formats you give it:  AC3, DTS, and almost anything else.  It gets decoded to uncompressed PCM.  So your 5.1 channel AC3 track turns into a 5.1 channel PCM track.  MC should then send that down the HDMI connection to your receiver.  Most receivers can handle multi-channel PCM, so you really don't need to do anything.  It should "just work".

However, if you prefer to have the receiver do the decoding, you can do that too.  To tell MC to not decode certain formats, use the bitstreaming option:

Tools > Options > Audio > Settings > Bitstreaming > Custom > (select your formats)

Note that bitstreaming means that MC can NOT touch the bits that get sent at all.  So, no volume control, no eq, no room correction, etc.  Nothing.  Your receiver will need to do any of those functions.

As I understand it, the "best practice" with MC and movie audio is to have MC decode it to PCM, so it can do any additional processing you might want.  But you have both options:  MC doing decoding, or your receiver doing decoding.

Brian.

[macdonjh]

Brian,

In my limited experience it doesn't just work yet.  I have only been able to get stereo-- even mono media (like MASH and other old TV shows) come out in the LF & RF speakers.  I'll try bit streaming as you suggest.  I haven't tried the room correction feature of MC yet, so I don't know what I'll be missing.

[macdonjh]

Bit streaming (by itself) didn't work, my pre-pro is still receiving a stereo signal.  Shoot.

[blgentry]

Look at:

Player > DSP Studio > Output Format > Channels

What is your channels set to?  It should be set to the number of speakers you have connected to your AVR.  In theory, this is what controls the format that MC sends out to your DAC/AVR/etc .

Just for additional information, you can look at:  Player > Audio Path

That will show you the input, the processing being done, and the exact output.

OH:  And when you change anything fundamental like this (bitstreaming for example), you probably need to stop and restart MC for it to take effect.

Brian.

[Hendrik]

Bitstreaming with video files is not supported on the Mac.
You can however just decode to full quality PCM and output that over HDMI, no need for bitstreaming to get the full quality.

[macdonjh]

Brian,

I found that I was set to 2 channel output in the DSP studio, so I changed it to 5.1 channels.  However, when playing a movie my pre-pro still received a stereo signal.  When I checked the settings in the DSP studio, MC21 had reverted to stereo.  I also tried the same experiment with bitstreaming turned off with the same results.

Hendrick, where do I set-up the decoding to PCM?  I think that's the next thing to try.

[blgentry]

I found that I was set to 2 channel output in the DSP studio, so I changed it to 5.1 channels.  However, when playing a movie my pre-pro still received a stereo signal.  When I checked the settings in the DSP studio, MC21 had reverted to stereo.

That implies that MC doesn't recognize your HDMI connection as being 5.1 channels.  MC seems to think that it is only a 2 channel device.  As I said above, I have no experience with MC and HDMI, so...

In Audio MIDI setup (OSX's audio configuration tool located in Applications/Utilities) how many channels does your HDMI device show?  From System Preferences/Sound can you play sound to all 5.1 of your speakers via HDMI?

Brian.

[macdonjh]

OK, so now I think I'm back to an Apple hardware issue.  Thanks for helping me find the audio set-up in OS-X.  My Mac is configured for stereo and all multi-channel options are greyed-out so I can't select them.

Do you know if that is a sound card issue, or is there a bit of software I need to enable multi-channel?

[BillT]

Being in the process of trying to extract multi channel audio from HDMI on a Windows machine (actually a Mac Mini running W7), it's quite likely to be an EDID/HDCP handshaking issue.

If the EDID data sent from the display device doesn't say it can handle the right sort of audio then the source will only output 48kHz mono stereo.

There seem to be ways round the issue which involve either a receiver which sends the right EDID data or a dongle which does the same thing.

For Windows you can do a software hack for some video cards which will let the card send multi-channel audio, unfortunately Intel built in graphics cards don't let you do a software hack so hardware is the only option.

[blgentry]

If you do some searching for HDMI multi-channel OS X you'll see a number of problems and solutions.  Sorry I can't help further.

Brian.