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[dvdr]

Hi
In my audio-editor, I created a multichannel 5.1 mix, which I exported as a single wav-file (I can either export the mix as single tracks per channel or all channels somehow merged in one file, that is still a multichannel file and no stereo downmixed file!)
Therefor, in file-properties, it properly says: it is a PCM (WaveFOrmatHeader), 6-channel, 96.000 Hz, 24bit file.
It plays in MC, but: what exactly does MC play:
- left and right channel only?
- a stereo-downmix of all channels, including Subwoofer-channel?
- does the windows-loudspeaker-properties setup have anything to do on how MC "downmixes"? (the portion, where you can choose, whether you have stereo desktop or laptopn or 5.1-channel speakers...)

I don't see any downmix-options in MC, so can I influence the downmix (if any occurs) in any way?

Please note: I am not talking about playback of DTS or AC3 files from video, but plain multichannel PCM-files.

[Matt]

If you have DSP Studio set to leave the audio format alone, MC should output the file in its native format -- 5.1 in this case. 

If you use DirectSound, it's possible DirectSound will downmix automatically depending on your driver and settings.

If you use ASIO, WaveOut, or DiskWriter, they won't open unless the native format is supported.

[dvdr]

Matt
thanks for answering. I am using ASIO (two channels activated), and I can open the file!!!!
Could the reason be, that my DAC (connected with firewire) is able to play 10 channels (it's recordings-studio-gear from RME Audio) and the ASIO-drivers support those 10 channels?
Still, I wonder, what channels MC would send to the activated 2 channels...
(I do not have DSP studio activated, since I want bitperfect playback)

[Alex B]

It seems that MC cannot "downmix" a 5.1 wave file.

If MC's DSP channel setting is not used MC always outputs 5.1 to my Terratec DMX 6fire 24/96 sound card. The card can play a 5.1 wave file correctly through its analog 5.1 outputs. I tried all three output modes (ASIO, DS and Wave).

The sound card's 2 channel driver option can only disable output to C, RL, RR and 0.1 channels, but not combine the channels to FL and FR.

If the DSP channel option inside MC is set to use a specific setting MC cannot play my test file at all. I guess that MC's DSP system is not designed to handle more than two audio input channels. Am I correct?

The 5.1 test file I used is available here: chanid.zip (360 kB)

[Matt]

MC's DSP Studio can convert 2 channels to 5.1 channels.  It doesn't currently have downmixing of 5.1 channels back to 2 channels.

[dvdr]

See, Matt, and that's why I was so astounded, that MC would play the file, I do hear a nice stereo-panorama, but of course, I cannot distinguish, whether MC just plays the FL/FR part of the file and leaves out C, RL, RR, Sub...
Since I do have a 10-Channel external FireWire-ASIO DAC (no built in (Dolby/DTS)decoders, each channel has to be adressed directly - as I said: recording-studio-gear), maybe the ASIO drivers only route the activated channels (in this case 1 & 2) through MC. What do you think? (I am a bit lost with my less than little knowledge about multichannel PCM files and ASIO drivers)

[Alex B]

MC's DSP Studio can convert 2 channels to 5.1 channels. It doesn't currently have downmixing of 5.1 channels back to 2 channels.

In general, it would be rather stupid to use a 4233 kbps (or more if higher resolution than 16/44.1) wave file for two channel stereo output.

Perhaps FFDShow's Direct Show filters could be used for downmixing the channels if the 5.1 PCM stream is placed in an AVI or a Matroska container file. (I am not going to test this anytime soon  ).

I cannot distinguish, whether MC just plays the FL/FR part of the file and leaves out C, RL, RR, Sub...

Try my test file.

EDIT

Does your souncard even have a standard 5.1 mode for home theater and similar usage? For example, can you configure the driver so that software decoded multichannel audio from a DVD video can be played through 6 of the 10 available channels?

[dvdr]

Does your souncard even have a standard 5.1 mode for home theater and similar usage? For example, can you configure the driver so that software decoded multichannel audio from a DVD video can be played through 6 of the 10 available channels?

Hi
I disabled the computer's internal soundcard to save resources, since I do not need it anyway.
But since you were talking about software decoding, here is what I found for Multichannel-DVD-Playback with software on the computer (which still is something different than opening this multichannel PCM-file from within MC...)

Multichannel
PowerDVD and WinDVD can also operate as software decoder, sending a DVD's multichannel
data stream directly to the analog outputs of the Fireface. All modes are supported, from 2 to 8 channels, at 16 bit resolution and up to 192 kHz sample rate. Up to 48 kHz, playback is also
possible via the ADAT outputs of the Fireface.
For multichannel playback, a WDM streaming* device, or the correct** MME playback device of the Fireface 800 has to be selected in >Control Panel/ Sounds and Multimedia/ Audio<. Also
check 'use preferred device only'. PowerDVD's audio properties now lists several multichannel
modes. If one of these is selected, PowerDVD sends the decoded analog multichannel data to
the Fireface.
* The option Interleaved in the Settings dialog has to be activated.
** Certain MME playback devices of the Fireface support multichannel playback (Interleaved) with 2, 4, 6 and 8 channels:
-- Fireface Analog (1+2): Up to 192 kHz, playback on the analog outputs 1-8
-- Fireface ADAT1 (1+2): Up to 48 kHz, playback on channels 13-20
-- Fireface ADAT2 (1+2): Up to 48 kHz, playback on channels 21-28
Thanks to TotalMix, the software's playback channels can be routed to any hardware outputs.
Therefore a playback at 96 kHz using the analog outputs can also be done via both ADAT
ports. This also removes a limitation in some software (like PowerDVD 5), which always uses
channel 1 as first channel of a multichannel playback.
The channel assignment using PowerDVD is:
1 - Left
2 - Right
3 - Center
4 - LFE (Low Frequency Effects)
5 - SL (Surround Left)
6 - SR (Surround Right)
Note 1: Selecting the Fireface to be used as system playback device is against our recommendations
on system optimization, as professional cards are not specialized to play back system
sounds, and shouldn't be disturbed by system events. To prevent this, be sure to re-assign the
selection after usage, or to disable any system sounds (tab Sounds, scheme 'No audio').
Note 2: The DVD player will be synced backwards from the Fireface. This means when using
AutoSync and/or word clock, the playback speed and pitch follows the incoming clock signal.

[Alex B]

I meant that if you can use a software decoder (e.g. PowerDVD or WinDVD) to output 6 separate channels with a certain sound card driver setting then MC's 5.1 wave playback should work just fine with the same setting.

As said before, MC always outputs 6 channels from a 6 channel wave file. You cannot change that inside MC.

EDIT

Depending on the sound card's ASIO driver you may need to use Direct Sound or Wave output instead of ASIO, but that does not really matter when the files are played for entertainment. (Terratec's ASIO driver works fine in 5.1 mode on my PC).

Normally you need to use a separate analog output channel for each of the 6 channels, so the output cannot be bit-perfect anyway (since it is analog, not digital).

ASIO's low latency and bit-perfect quality are perhaps more important factors in a production environment.

[dvdr]

Hi

it might be of interest for you, what I ended up with and found out:

When I play 6-channel pcm-files (or flacs made of them) and use the ASIO-driver of the DAC (RME-Audio FireFace800), MC passes along the files to my DAC and uses 6 channels from my 10.channel DAC. In other words: left and right are passed to the first two channels, followed by center, LFE, Back left, Back right which all get a dedicated channel on the DAC.
There is no influence whatsover by MC, it does not downmix  or so... So I guess for all those, who have a two-channel DAC, they will get the front channels only.

As to your remark of bitperfect playback - being a HighEnd-afficionado, I do care! That's why I use ASIO instead of anything else