Threaded Mode | Linear Mode

***spacy51*** · 07-15-2008 03:45 AM

Hey there, I just added the feature to upmix the GB's/GBA's stereo sound to the number of speakers which are attached to the souncard.

I took this inof sheet as a reference:
http://ac3filter.net/guides/mixing_matrix

And this for the speaker order:
http://msdn.microsoft.com/en-us/library/bb694506.aspx

Here are my matrices. Since I entered them by hand, it would be good if everyone who is into that stuff could tell me if they're good.
Is it OK if I leave the LFE always at 0 since it would receive frequencies higher than for ex. 120Hz?
I can still hear my LFE because my sound driver uses a crossover frequency to get the subwoofer signal from the low-freq part of the other channels.

PHP Code:

#ifdef STEREO_UPMIXING
    // set up stereo upmixing
    XAUDIO2_DEVICE_DETAILS dd;
    ZeroMemory( &dd, sizeof( dd ) );
    hr = xaud->GetDeviceDetails( 0, &dd );
    ASSERT( hr == S_OK );
    float *matrix = NULL;
    matrix = (float*)malloc( sizeof( float ) * 2 * dd.OutputFormat.Format.nChannels );
    switch( dd.OutputFormat.Format.nChannels ) {
        case 4: // 4.0
//Speaker \ Left Source           Right Source
/*Front L*/    matrix[0] = 1.0000f;  matrix[1] = 0.0000f;
/*Front R*/    matrix[2] = 0.0000f;  matrix[3] = 1.0000f;
/*Back  L*/    matrix[4] = 1.0000f;  matrix[5] = 0.0000f;
/*Back  R*/    matrix[6] = 0.0000f;  matrix[7] = 1.0000f;
            break;
        case 5: // 5.0
//Speaker \ Left Source           Right Source
/*Front L*/    matrix[0] = 1.0000f;  matrix[1] = 0.0000f;
/*Front R*/    matrix[2] = 0.0000f;  matrix[3] = 1.0000f;
/*Front C*/    matrix[4] = 0.7071f;  matrix[5] = 0.7071f;
/*Side  L*/    matrix[6] = 1.0000f;  matrix[7] = 0.0000f;
/*Side  R*/    matrix[8] = 0.0000f;  matrix[9] = 1.0000f;
            break;
        case 6: // 5.1
//Speaker \ Left Source           Right Source
/*Front L*/    matrix[0] = 1.0000f;  matrix[1] = 0.0000f;
/*Front R*/    matrix[2] = 0.0000f;  matrix[3] = 1.0000f;
/*Front C*/    matrix[4] = 0.7071f;  matrix[5] = 0.7071f;
/*LFE    */    matrix[6] = 0.0000f;  matrix[7] = 0.0000f;
/*Side  L*/    matrix[8] = 1.0000f;  matrix[9] = 0.0000f;
/*Side  R*/    matrix[10] = 0.0000f;  matrix[11] = 1.0000f;
            break;
        case 7: // 6.1
//Speaker \ Left Source           Right Source
/*Front L*/    matrix[0] = 1.0000f;  matrix[1] = 0.0000f;
/*Front R*/    matrix[2] = 0.0000f;  matrix[3] = 1.0000f;
/*Front C*/    matrix[4] = 0.7071f;  matrix[5] = 0.7071f;
/*LFE    */    matrix[6] = 0.0000f;  matrix[7] = 0.0000f;
/*Side  L*/    matrix[8] = 1.0000f;  matrix[9] = 0.0000f;
/*Side  R*/    matrix[10] = 0.0000f;  matrix[11] = 1.0000f;
/*Back  C*/    matrix[12] = 0.7071f;  matrix[13] = 0.7071f;
            break;
        case 8: // 7.1
//Speaker \ Left Source           Right Source
/*Front L*/    matrix[0] = 1.0000f;  matrix[1] = 0.0000f;
/*Front R*/    matrix[2] = 0.0000f;  matrix[3] = 1.0000f;
/*Front C*/    matrix[4] = 0.7071f;  matrix[5] = 0.7071f;
/*LFE    */    matrix[6] = 0.0000f;  matrix[7] = 0.0000f;
/*Back  L*/    matrix[8] = 1.0000f;  matrix[9] = 0.0000f;
/*Back  R*/    matrix[10] = 0.0000f;  matrix[11] = 1.0000f;
/*Side  L*/    matrix[12] = 1.0000f;  matrix[13] = 0.0000f;
/*Side  R*/    matrix[14] = 0.0000f;  matrix[15] = 1.0000f;
            break;
    }
    hr = sVoice->SetOutputMatrix( NULL, 2, dd.OutputFormat.Format.nChannels, matrix );
    ASSERT( hr == S_OK );
    free( matrix );
    matrix = NULL;
#endif 

***Squall Leonhart*** · 07-15-2008 05:22 PM

LFE crossmixing should be made adjustable, as not all sound drivers mix LFE channels.

my main pc's Logitech Z640 and creative SB Live make a virtual surround already, though since i've been gaming on my other pc lately, i use my HTS's DPLII mixing.

***spacy51*** · 07-15-2008 08:50 PM

Well, the problem is I have no idea if setting up a crossover frequency is possible with XAudio2.

Squall Leonhart Wrote:LFE crossmixing should be made adjustable, as not all sound drivers mix LFE channels.

my main pc's Logitech Z640 and creative SB Live make a virtual surround already, though since i've been gaming on my other pc lately, i use my HTS's DPLII mixing.

***Squall Leonhart*** · 07-15-2008 10:15 PM

you should totally make an Xaudio plugin for Project64 Tongue

Threaded Mode \| Linear Mode XAudio2 upmixing matrices
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