audiotestsrc

audiotestsrc — Creates audio test signals of given frequency and volume

Synopsis

                    GstAudioTestSrc;
enum                GstAudioTestSrcWave;

Object Hierarchy

  GObject
   +----GstObject
         +----GstElement
               +----GstBaseSrc
                     +----GstAudioTestSrc

Properties

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

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

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). 
gst-launch audiotestsrc wave=2 freq=200 ! audioconvert ! tee name=t ! queue ! alsasink t. ! queue ! libvisual_lv_scope ! ffmpegcolorspace ! 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-int, endianness=(int)1234, signed=(boolean)true, width=(int)16, depth=(int)16, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2 ]
audio/x-raw-int, endianness=(int)1234, signed=(boolean)true, width=(int)32, depth=(int)32, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2 ]
audio/x-raw-float, endianness=(int)1234, width=(int){ 32, 64 }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2 ]

Details

GstAudioTestSrc

typedef struct _GstAudioTestSrc GstAudioTestSrc;

audiotestsrc object structure.

enum GstAudioTestSrcWave

typedef enum {
  GST_AUDIO_TEST_SRC_WAVE_SINE,
  GST_AUDIO_TEST_SRC_WAVE_SQUARE,
  GST_AUDIO_TEST_SRC_WAVE_SAW,
  GST_AUDIO_TEST_SRC_WAVE_TRIANGLE,
  GST_AUDIO_TEST_SRC_WAVE_SILENCE,
  GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE,
  GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE,
  GST_AUDIO_TEST_SRC_WAVE_SINE_TAB,
  GST_AUDIO_TEST_SRC_WAVE_TICKS,
  GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE
} GstAudioTestSrcWave;

Different types of supported sound waves.

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.

Property Details

The "freq" property

  "freq"                     gdouble               : Read / Write

Frequency of test signal.

Allowed values: [0,20000]

Default value: 440

The "is-live" property

  "is-live"                  gboolean              : Read / Write

Whether to act as a live source.

Default value: FALSE

The "samplesperbuffer" property

  "samplesperbuffer"         gint                  : Read / Write

Number of samples in each outgoing buffer.

Allowed values: >= 1

Default value: 1024

The "timestamp-offset" property

  "timestamp-offset"         gint64                : Read / Write

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

Default value: 0

The "volume" property

  "volume"                   gdouble               : Read / Write

Volume of test signal.

Allowed values: [0,1]

Default value: 0.8

The "wave" property

  "wave"                     GstAudioTestSrcWave   : Read / Write

Oscillator waveform.

Default value: Sine

The "can-activate-pull" property

  "can-activate-pull"        gboolean              : Read / Write

Can activate in pull mode.

Default value: FALSE

The "can-activate-push" property

  "can-activate-push"        gboolean              : Read / Write

Can activate in push mode.

Default value: TRUE

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