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gst/filter/gstlpwsinc.*: Allow choosing between hamming and blackman window. The blackman window provides a better st...

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Original commit message from CVS:
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_window_get_type),
(gst_lpwsinc_class_init), (gst_lpwsinc_init),
(lpwsinc_build_kernel), (lpwsinc_set_property),
(lpwsinc_get_property):
* gst/filter/gstlpwsinc.h:
Allow choosing between hamming and blackman window. The blackman
window provides a better stopband attenuation but a bit slower
rolloff.
This commit is contained in:
Sebastian Dröge 2007-08-10 04:32:47 +00:00
parent 882fd5c387
commit 982bf23b35
3 changed files with 62 additions and 3 deletions
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11
ChangeLog
View file

@ -1,3 +1,14 @@
2007-08-10 Sebastian Dröge <slomo@circular-chaos.org>
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_window_get_type),
(gst_lpwsinc_class_init), (gst_lpwsinc_init),
(lpwsinc_build_kernel), (lpwsinc_set_property),
(lpwsinc_get_property):
* gst/filter/gstlpwsinc.h:
Allow choosing between hamming and blackman window. The blackman
window provides a better stopband attenuation but a bit slower
rolloff.
2007-08-10 Sebastian Dröge <slomo@circular-chaos.org>
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_mode_get_type),

53
gst/filter/gstlpwsinc.c
View file

@ -29,7 +29,6 @@
* TODO: - Implement the convolution in place, probably only makes sense
* when using FFT convolution as currently the convolution itself
* is probably the bottleneck.
* - Allow choosing between different windows (blackman, hanning, ...)
* - Maybe allow cascading the filter to get a better stopband attenuation.
* Can be done by convolving a filter kernel with itself.
*/
@ -69,7 +68,8 @@ enum
PROP_0,
PROP_LENGTH,
PROP_FREQUENCY,
PROP_MODE
PROP_MODE,
PROP_WINDOW
};
enum
@ -98,6 +98,33 @@ gst_lpwsinc_mode_get_type (void)
return gtype;
}
enum
{
WINDOW_HAMMING = 0,
WINDOW_BLACKMAN
};
#define GST_TYPE_LPWSINC_WINDOW (gst_lpwsinc_window_get_type ())
static GType
gst_lpwsinc_window_get_type (void)
{
static GType gtype = 0;
if (gtype == 0) {
static const GEnumValue values[] = {
{WINDOW_HAMMING, "Hamming window (default)",
"hamming"},
{WINDOW_BLACKMAN, "Blackman window",
"blackman"},
{0, NULL, NULL}
};
gtype = g_enum_register_static ("GstLPWSincWindow", values);
}
return gtype;
}
#define ALLOWED_CAPS \
"audio/x-raw-float," \
" width = (int) { 32, 64 }, " \
@ -185,6 +212,11 @@ gst_lpwsinc_class_init (GstLPWSincClass * klass)
"Low pass or high pass mode", GST_TYPE_LPWSINC_MODE,
MODE_LOW_PASS, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
g_object_class_install_property (gobject_class, PROP_WINDOW,
g_param_spec_enum ("window", "Window",
"Window function to use", GST_TYPE_LPWSINC_WINDOW,
WINDOW_HAMMING, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
trans_class->transform = GST_DEBUG_FUNCPTR (lpwsinc_transform);
trans_class->get_unit_size = GST_DEBUG_FUNCPTR (lpwsinc_get_unit_size);
GST_AUDIO_FILTER_CLASS (klass)->setup = GST_DEBUG_FUNCPTR (lpwsinc_setup);
@ -193,6 +225,8 @@ gst_lpwsinc_class_init (GstLPWSincClass * klass)
static void
gst_lpwsinc_init (GstLPWSinc * self, GstLPWSincClass * g_class)
{
self->mode = MODE_LOW_PASS;
self->window = WINDOW_HAMMING;
self->wing_size = 50;
self->frequency = 0.0;
self->kernel = NULL;
@ -292,7 +326,11 @@ lpwsinc_build_kernel (GstLPWSinc * self)
else
self->kernel[i] = sin (w * (i - len)) / (i - len);
/* windowing */
self->kernel[i] *= (0.54 - 0.46 * cos (M_PI * i / len));
if (self->window == WINDOW_HAMMING)
self->kernel[i] *= (0.54 - 0.46 * cos (M_PI * i / len));
else
self->kernel[i] *=
(0.42 - 0.5 * cos (M_PI * i / len) + 0.08 * cos (2 * M_PI * i / len));
}
/* normalize for unity gain at DC */
@ -414,6 +452,12 @@ lpwsinc_set_property (GObject * object, guint prop_id, const GValue * value,
lpwsinc_build_kernel (self);
GST_BASE_TRANSFORM_UNLOCK (self);
break;
case PROP_WINDOW:
GST_BASE_TRANSFORM_LOCK (self);
self->window = g_value_get_enum (value);
lpwsinc_build_kernel (self);
GST_BASE_TRANSFORM_UNLOCK (self);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
@ -436,6 +480,9 @@ lpwsinc_get_property (GObject * object, guint prop_id, GValue * value,
case PROP_MODE:
g_value_set_enum (value, self->mode);
break;
case PROP_WINDOW:
g_value_set_enum (value, self->window);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;

1
gst/filter/gstlpwsinc.h
View file

@ -67,6 +67,7 @@ struct _GstLPWSinc {
GstLPWSincProcessFunc process;
gint mode;
gint window;
gdouble frequency;
gint wing_size; /* length of a "wing" of the filter;
actual length is 2 * wing_size + 1 */