audiomixmatrix

This element transforms a given number of input channels into a given number of output channels according to a given transformation matrix. The matrix coefficients must be between -1 and 1: the number of rows is equal to the number of output channels and the number of columns is equal to the number of input channels. In the first-channels mode, input/output channels are automatically negotiated and the transformation matrix is a truncated identity matrix.

Example matrix generation code

To generate the matrix using code:

 GValue v = G_VALUE_INIT;
 GValue v2 = G_VALUE_INIT;
 GValue v3 = G_VALUE_INIT;

 g_value_init (&v2, GST_TYPE_ARRAY);
 g_value_init (&v3, G_TYPE_DOUBLE);
 g_value_set_double (&v3, 1);
 gst_value_array_append_value (&v2, &v3);
 g_value_unset (&v3);
 [ Repeat for as many double as your input channels - unset and reinit v3 ]
 g_value_init (&v, GST_TYPE_ARRAY);
 gst_value_array_append_value (&v, &v2);
 g_value_unset (&v2);
 [ Repeat for as many v2's as your output channels - unset and reinit v2]
 g_object_set_property (G_OBJECT (audiomixmatrix), "matrix", &v);
 g_value_unset (&v);

Example launch line

 gst-launch-1.0 audiotestsrc ! audio/x-raw,channels=4 ! audiomixmatrix in-channels=4 out-channels=2 channel-mask=-1 matrix="<<(double)1, (double)0, (double)0, (double)0>, <0.0, 1.0, 0.0, 0.0>>" ! audio/x-raw,channels=2 ! autoaudiosink