GStreamer Base Plugins 1.0 Plugins Reference Manual: audiotestsrc

## audiotestsrc audiotestsrc — Creates audio test signals of given frequency and volume |

## Properties

gboolean | can-activate-pull | Read / Write
gboolean | can-activate-push | Read / Write
gdouble | freq | Read / Write
gboolean | is-live | Read / Write
gint | samplesperbuffer | Read / Write
gint64 | timestamp-offset | Read / Write
gdouble | volume | Read / Write
GstAudioTestSrcWave | wave | Read / Write

## Types and Values

struct | GstAudioTestSrc
enum | GstAudioTestSrcWave

## Object Hierarchy

        GObject
        ╰── GInitiallyUnowned
            ╰── GstObject
                ╰── GstElement
                    ╰── GstBaseSrc
                        ╰── GstAudioTestSrc

## Description

AudioTestSrc can be used to generate basic audio signals. It support several different waveforms and allows to set the base frequency and volume.

### Example launch line

    1
    gst-launch audiotestsrc ! audioconvert ! alsasink

This pipeline produces a sine with default frequency, 440 Hz, and the default volume, 0.8 (relative to a maximum 1.0).

    1
    gst-launch audiotestsrc wave=2 freq=200 ! audioconvert ! tee name=t ! queue ! alsasink t. ! queue ! libvisual_lv_scope ! videoconvert ! xvimagesink

In this example a saw wave is generated. The wave is shown using a scope visualizer from libvisual, allowing you to visually verify that the saw wave is correct.

## Synopsis

### Element Information

plugin | audiotestsrc
author | Stefan Kost <ensonic@users.sf.net>
class | Source/Audio

### Element Pads

name | src
direction | source
presence | always
details | audio/x-raw, format=(string){ S16LE, S32LE, F32LE, F64LE }, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2 ]

## Functions

## Types and Values

### struct GstAudioTestSrc

    struct GstAudioTestSrc;

audiotestsrc object structure.

### enum GstAudioTestSrcWave

Different types of supported sound waves.

#### Members

GST_AUDIO_TEST_SRC_WAVE_SINE | a sine wave |
GST_AUDIO_TEST_SRC_WAVE_SQUARE | a square wave |
GST_AUDIO_TEST_SRC_WAVE_SAW | a saw wave |
GST_AUDIO_TEST_SRC_WAVE_TRIANGLE | a tringle wave |
GST_AUDIO_TEST_SRC_WAVE_SILENCE | silence |
GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE | white uniform noise |
GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE | pink noise |
GST_AUDIO_TEST_SRC_WAVE_SINE_TAB | sine wave using a table |
GST_AUDIO_TEST_SRC_WAVE_TICKS | periodic ticks |
GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE | white (zero mean) Gaussian noise; volume sets the standard deviation of the noise in units of the range of values of the sample type, e.g. volume=0.1 produces noise with a standard deviation of 0.1*32767=3277 with 16-bit integer samples, or 0.1*1.0=0.1 with floating-point samples. |
GST_AUDIO_TEST_SRC_WAVE_RED_NOISE | red (brownian) noise |
GST_AUDIO_TEST_SRC_WAVE_BLUE_NOISE | spectraly inverted pink noise |
GST_AUDIO_TEST_SRC_WAVE_VIOLET_NOISE | spectraly inverted red (brownian) noise |

## Property Details

### The `“can-activate-pull”` property

      “can-activate-pull”        gboolean

Can activate in pull mode.

Flags: Read / Write

Default value: FALSE

### The `“can-activate-push”` property

      “can-activate-push”        gboolean

Can activate in push mode.

Flags: Read / Write

Default value: TRUE

### The `“freq”` property

      “freq”                     gdouble

Frequency of test signal.

Flags: Read / Write

Allowed values: [0,20000]

Default value: 440

### The `“is-live”` property

      “is-live”                  gboolean

Whether to act as a live source.

Flags: Read / Write

Default value: FALSE

### The `“samplesperbuffer”` property

      “samplesperbuffer”         gint

Number of samples in each outgoing buffer.

Flags: Read / Write

Allowed values: >= 1

Default value: 1024

### The `“timestamp-offset”` property

      “timestamp-offset”         gint64

An offset added to timestamps set on buffers (in ns).

Flags: Read / Write

Default value: 0

### The `“volume”` property

      “volume”                   gdouble

Volume of test signal.

Flags: Read / Write

Allowed values: [0,1]

Default value: 0.8

### The `“wave”` property

      “wave”                     GstAudioTestSrcWave

Oscillator waveform.

Flags: Read / Write

Default value: Sine