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

Description

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

Example launch line

gst-launch audiotestsrc ! audioconvert ! alsasink

This pipeline produces a sine with default frequency (mid-C) and volume.

gst-launch audiotestsrc wave=2 freq=200 ! audioconvert ! tee name=t ! alsasink t. ! 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.

Element Information

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

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
} 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 noise
GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE pink noise
GST_AUDIO_TEST_SRC_WAVE_SINE_TAB sine wave using a table

Properties

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