#include <string.h>
#include <gst/gst.h>
#include <gst/base/gstbasetransform.h>
#include <gst/audio/audio.h>
#include <gst/audio/gstaudiofilter.h>
#include <math.h>
#include "math_compat.h"
#include "audiocheblimit.h"
#include "gst/glib-compat-private.h"

Include dependency graph for audiocheblimit.c:

Macros
#define	GST_CAT_DEFAULT gst_audio_cheb_limit_debug

#define	gst_audio_cheb_limit_parent_class parent_class

#define	GST_TYPE_AUDIO_CHEBYSHEV_FREQ_LIMIT_MODE (gst_audio_cheb_limit_mode_get_type ())

Enumerations
enum	{ PROP_0 , PROP_MODE , PROP_TYPE , PROP_CUTOFF , PROP_RIPPLE , PROP_POLES }

enum	{ MODE_LOW_PASS = 0 , MODE_HIGH_PASS }

Functions
	GST_DEBUG_CATEGORY_STATIC (gst_audio_cheb_limit_debug)

	G_DEFINE_TYPE (GstAudioChebLimit, gst_audio_cheb_limit,(gst_audio_fx_base_iir_filter_get_type()))

	GST_ELEMENT_REGISTER_DEFINE (audiocheblimit, "audiocheblimit", GST_RANK_NONE,(gst_audio_cheb_limit_get_type()))

static void	gst_audio_cheb_limit_set_property (GObject object, guint prop_id, const GValue value, GParamSpec *pspec)

static void	gst_audio_cheb_limit_get_property (GObject object, guint prop_id, GValue value, GParamSpec *pspec)

static void	gst_audio_cheb_limit_finalize (GObject *object)

static gboolean	gst_audio_cheb_limit_setup (GstAudioFilter filter, const GstAudioInfo info)

static GType	gst_audio_cheb_limit_mode_get_type (void)

static void	gst_audio_cheb_limit_class_init (GstAudioChebLimitClass *klass)

static void	gst_audio_cheb_limit_init (GstAudioChebLimit *filter)

static void	generate_biquad_coefficients (GstAudioChebLimit filter, gint p, gint rate, gdouble b0, gdouble b1, gdouble b2, gdouble a1, gdouble a2)

static void	generate_coefficients (GstAudioChebLimit filter, const GstAudioInfo info)

Macro Definition Documentation

◆ gst_audio_cheb_limit_parent_class

#define gst_audio_cheb_limit_parent_class parent_class

Definition at line 95 of file audiocheblimit.c.

◆ GST_CAT_DEFAULT

#define GST_CAT_DEFAULT gst_audio_cheb_limit_debug

SECTION:element-audiocheblimit @title: audiocheblimit

Attenuates all frequencies above the cutoff frequency (low-pass) or all frequencies below the cutoff frequency (high-pass). The number of poles and the ripple parameter control the rolloff.

This element has the advantage over the windowed sinc lowpass and highpass filter that it is much faster and produces almost as good results. It's only disadvantages are the highly non-linear phase and the slower rolloff compared to a windowed sinc filter with a large kernel.

For type 1 the ripple parameter specifies how much ripple in dB is allowed in the passband, i.e. some frequencies in the passband will be amplified by that value. A higher ripple value will allow a faster rolloff.

For type 2 the ripple parameter specifies the stopband attenuation. In the stopband the gain will be at most this value. A lower ripple value will allow a faster rolloff.

As a special case, a Chebyshev type 1 filter with no ripple is a Butterworth filter.

‍Be warned that a too large number of poles can produce noise. The most poles are possible with a cutoff frequency at a quarter of the sampling rate.

Example launch line

|[ gst-launch-1.0 audiotestsrc freq=1500 ! audioconvert ! audiocheblimit mode=low-pass cutoff=1000 poles=4 ! audioconvert ! alsasink gst-launch-1.0 filesrc location="melo1.ogg" ! oggdemux ! vorbisdec ! audioconvert ! audiocheblimit mode=high-pass cutoff=400 ripple=0.2 ! audioconvert ! alsasink gst-launch-1.0 audiotestsrc wave=white-noise ! audioconvert ! audiocheblimit mode=low-pass cutoff=800 type=2 ! audioconvert ! alsasink ]|

Definition at line 82 of file audiocheblimit.c.