audiomixmatrix

audiomixmatrix — Transform input/output channels according to a matrix

Properties

guint64 channel-mask Read / Write
guint in-channels Read / Write
GstValueArray matrix Read / Write
GValueArray * matrix-value-array Read / Write
GstAudioMixMatrixModeType mode Read / Write
guint out-channels Read / Write

Types and Values

struct GstAudioMixMatrix

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstBaseTransform
                    ╰── GstAudioMixMatrix

Description

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:

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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

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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

Synopsis

Element Information

plugin

 audiomixmatrix

author

 Vivia Nikolaidou <vivia@toolsonair.com>

class

 Filter/Audio

Element Pads

name

 sink

direction

 sink

presence

 always

details

 audio/x-raw, channels=(int)[ 1, 2147483647 ], layout=(string)interleaved, format=(string){ F32LE, F64LE, S16LE, S32LE }

name

 src

direction

 source

presence

 always

details

 audio/x-raw, channels=(int)[ 1, 2147483647 ], layout=(string)interleaved, format=(string){ F32LE, F64LE, S16LE, S32LE }

Functions

Types and Values

struct GstAudioMixMatrix

struct GstAudioMixMatrix;

Opaque data structure.

Property Details

The “channel-mask” property

  “channel-mask”             guint64

Output channel mask (-1 means "default for these channels").

Flags: Read / Write

Default value: 0

The “in-channels” property

  “in-channels”              guint

How many audio channels we have on the input side.

Flags: Read / Write

Allowed values: <= 64

Default value: 0

The “matrix” property

  “matrix”                   GstValueArray

Transformation matrix for input/output channels.

Flags: Read / Write

The “matrix-value-array” property

  “matrix-value-array”       GValueArray *

Transformation matrix (GValueArray) for input/output channels.

Flags: Read / Write

The “mode” property

  “mode”                     GstAudioMixMatrixModeType

Whether to auto-negotiate input/output channels and matrix.

Flags: Read / Write

Default value: Manual mode: please specify input/output channels and transformation matrix

The “out-channels” property

  “out-channels”             guint

How many audio channels we have on the output side.

Flags: Read / Write

Allowed values: <= 64

Default value: 0

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