MultiChannel Problems

#1

Hi… I’ve this problem:
I have to use 8 audio channels in output.
So, i choose the sound card and select the 8 channels, but the “audiosamplebuffer info” that i use in the getNextAudioBlock has always just 2 channels; it let me stream audio just to the first two channel selected in the selector (eg, if i select 1…8 audio comes out from monitor 1&2, if i deselect channels 1&2 audio comes out from monitor 3&4…)
I think that when i choose the sound card in the AudioDeviceSelectorComponent it has to change the channel number in the buffer… but nothing!

Let me know what it’s possible that i miss

thanks and forgive me for my english

Marcello

#2

The number of channels is set in AudioDeviceManager::initialise().

#3

so it’s not atomatic that if i select 8 (or more…) channel in the selector the buffer will become an 8 channel uffer??

but anyhow, when i create the devicemanager i do this:

const String error (audioDeviceManager.initialise (1, /* number of input channels */
                        8, /* number of output channels */
                        0, /* no XML settings.. */
                        true  /* select default device on failure */));

    if (error.isNotEmpty())
    {
        AlertWindow::showMessageBox (AlertWindow::WarningIcon,
                                     T("Audio Demo"),
                                     T("Couldn't open an output device!\n\n") + error);
    }
    else
    {

        // ..and connect the mixer to our source player.
        audioSourcePlayer.setSource (&transportSource2);

        // start the IO device pulling its data from our callback..
        audioDeviceManager.setAudioCallback (this);

       /* other stuff */
    }
		audioSettingsComp=new AudioDeviceSelectorComponent (              audioDeviceManager,
                                                            0, 1,
                                                            2, 8,
                                                            true);
		audioSettingsComp->setSize (500, 300);

but always just 2 channels opened…
maybe it’s becouse, by default, my app first open a sound card with 2 chan out… then i choose the other one…

let me know…

thanks jules

#4

Well if you’ve only got 2 channels active then the callback just gives you a buffer containing those 2 channels.

#5

so, after selecting the new device i got to call the initialise(…); right?

#6

No, you don’t have to call it again. Sorry, I’m not sure I understand exactly what the problem is?

#7

Maybe it’s becouse of my english… :smiley:
Ok, let me explain better than before…

In the constructor of the main component i do this:

const String error (audioDeviceManager.initialise (1, /* number of input channels */
                        8, /* number of output channels */
                        0, /* no XML settings.. */
                        true  /* select default device on failure */));

    if (error.isNotEmpty())
    {
        AlertWindow::showMessageBox (AlertWindow::WarningIcon,
                                     T("Audio Demo"),
                                     T("Couldn't open an output device!\n\n") + error);
    }
    else
    {

        // ..and connect the mixer to our source player.
        audioSourcePlayer.setSource (&transportSource2);

        // start the IO device pulling its data from our callback..
        audioDeviceManager.setAudioCallback (this);

       /* other stuff */
    }
      audioSettingsComp=new AudioDeviceSelectorComponent (              audioDeviceManager,
                                                            0, 1,
                                                            2, 8,
                                                            true);

When i run the app, it choose the default audiodevice that has 2 output channels.

Then I open the AudioDeviceSelectorComponent and choose the other audiodevice selecting all the 8 output channels.

But when i “play” audio just the first 2 channels selected (1&2 or, if 1&2 are uncecked, 3&4…) will stream audio; this (i think) becouse info.buffer in the getNextAudioBlock got still 2 output channels.

I thought that selecting the right audiodevice and selecting the output channels to open then info.buffer would change with it.

I hope you understand what i mean…

Thanks

#8

Ok. If you can select and activate 8 channels in the audio device panel, then the audio device will definitely be delivering an 8-channel buffer in its callback…

But I think I recently fixed the AudioSourcePlayer code because that was only passing on the first two channels to the audio source… Are you using the latest juce version?

#9

I got Juce 1.41…
Could be this???
let me know…

#10

Yes, try the latest one.

#11

Nothing…
I try to open just 1 channel to test, but when debugging i find just 2 channel for the info.buffer!!!

Just to tell you: when I choose the asio device in the selector and also choose all the 8 channels in the output tab of VC++ appear:

in  0 0
out 1 0
out 2 1
out 3 2
out 4 3
out 5 4
out 6 5
out 7 6
out 8 7

I really don’t know what it is and what to do…

help me…

#12

I’m working on some multi-channel apps at the moment and they work just fine, so it’s very unlikely to be a bug - you must just be misunderstanding something.

The debug info shows that it is opening that many channels, so I assume you’re getting them in your callback. Sorry, without seeing all your code I can’t guess what else you might be missing…

#13

I compiled the jucedemo to see if i did something stupid… but even with it just 2 channels spray audio…
what da hell!!!

#14

breaking news:

I told you i try with the jucedemo…
now, with the audio sound (cello) it do not work… but it work with the mid, all the channels!!!

wow… but what it means???

#15

Eh? Of course the cello only uses 2 channels, it’s a stereo sample. And the demo’s only designed to use 2 channels anyway. Not sure I understand what you think is wrong?

#16

let me explain…
i modified the jucedemo code to use asio device and then i select my device (that allow to use up to 10 out channels).
Now if i play midi it sounds good…
i know that cello is a stereo file but i thought, maybe i was wrong, that it would play the same…

#17

So there’s no problem, right?

#18

uhm… no, problems remain!
but i don’t want to bore you anymore… today!!! :smiley:
i will try… i got to play audiosample in all the channels…
so I will try!

See you tomorrow Jules :slight_smile:

ps: thanks

#19

hi, here I am again…
Let me explain the actual situation; i got something like this:

AudioSourcePlayer <-- TransportSource <-- MyMixer <-- Filter0 <-- Channel0
                                                  <-- Filter1 <-- Channel1
                                                  <-- FilterN <-- ChannelN

where MyMixer, Filter and Channel inherit from PositionableAudioSource.
In this situation I can play, stop and other but the channel number for MyMixer is always 2!

if I try this:

AudioSourcePlayer <-- MyMixer <-- Filter0 <-- Channel0
                              <-- Filter1 <-- Channel1
                              <-- FilterN <-- ChannelN

it let me change the channel number in MyMixer in whatever I choose in the AudioDeviceSelector… but, obviously, becouse of there’s no transportsource, i cannot start playing and other…

Help me find the solution to my sick problem…

thanks

#20

Sorry, I still don’t understand - exactly which class are you saying is not working, and in what way is it failing?