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gst/filter/gstlpwsinc.*: Specify the actual filter length instead of a weird 2N+1. Setting the property will round to...

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Original commit message from CVS:
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_class_init),
(gst_lpwsinc_init), (process_32), (process_64),
(lpwsinc_build_kernel), (lpwsinc_set_property),
(lpwsinc_get_property):
* gst/filter/gstlpwsinc.h:
Specify the actual filter length instead of a weird
2N+1. Setting the property will round to the next odd number.
Also remove now obsolete FIXMEs.
This commit is contained in:
Sebastian Dröge 2007-08-10 04:44:43 +00:00
parent 982bf23b35
commit 11131b7a44
3 changed files with 40 additions and 28 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_class_init),
(gst_lpwsinc_init), (process_32), (process_64),
(lpwsinc_build_kernel), (lpwsinc_set_property),
(lpwsinc_get_property):
* gst/filter/gstlpwsinc.h:
Specify the actual filter length instead of a weird
2N+1. Setting the property will round to the next odd number.
Also remove now obsolete FIXMEs.
2007-08-10 Sebastian Dröge <slomo@circular-chaos.org> 2007-08-10 Sebastian Dröge <slomo@circular-chaos.org>
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_window_get_type), * gst/filter/gstlpwsinc.c: (gst_lpwsinc_window_get_type),

50
gst/filter/gstlpwsinc.c
View file

@ -204,8 +204,8 @@ gst_lpwsinc_class_init (GstLPWSincClass * klass)
g_object_class_install_property (gobject_class, PROP_LENGTH, g_object_class_install_property (gobject_class, PROP_LENGTH,
g_param_spec_int ("length", "Length", g_param_spec_int ("length", "Length",
"N such that the filter length = 2N + 1", "Filter kernel length, will be rounded to the next odd number",
1, G_MAXINT, 1, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE)); 3, G_MAXINT, 101, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
g_object_class_install_property (gobject_class, PROP_MODE, g_object_class_install_property (gobject_class, PROP_MODE,
g_param_spec_enum ("mode", "Mode", g_param_spec_enum ("mode", "Mode",
@ -227,7 +227,7 @@ gst_lpwsinc_init (GstLPWSinc * self, GstLPWSincClass * g_class)
{ {
self->mode = MODE_LOW_PASS; self->mode = MODE_LOW_PASS;
self->window = WINDOW_HAMMING; self->window = WINDOW_HAMMING;
self->wing_size = 50; self->kernel_length = 101;
self->frequency = 0.0; self->frequency = 0.0;
self->kernel = NULL; self->kernel = NULL;
self->residue = NULL; self->residue = NULL;
@ -238,7 +238,7 @@ gst_lpwsinc_init (GstLPWSinc * self, GstLPWSincClass * g_class)
static void static void
process_32 (GstLPWSinc * self, gfloat * src, gfloat * dst, guint input_samples) process_32 (GstLPWSinc * self, gfloat * src, gfloat * dst, guint input_samples)
{ {
gint kernel_length = self->wing_size * 2 + 1; gint kernel_length = self->kernel_length;
gint i, j, k, l; gint i, j, k, l;
gint channels = GST_AUDIO_FILTER (self)->format.channels; gint channels = GST_AUDIO_FILTER (self)->format.channels;
@ -265,7 +265,7 @@ static void
process_64 (GstLPWSinc * self, gdouble * src, gdouble * dst, process_64 (GstLPWSinc * self, gdouble * src, gdouble * dst,
guint input_samples) guint input_samples)
{ {
gint kernel_length = self->wing_size * 2 + 1; gint kernel_length = self->kernel_length;
gint i, j, k, l; gint i, j, k, l;
gint channels = GST_AUDIO_FILTER (self)->format.channels; gint channels = GST_AUDIO_FILTER (self)->format.channels;
@ -297,8 +297,8 @@ lpwsinc_build_kernel (GstLPWSinc * self)
gdouble w; gdouble w;
/* fill the kernel */ /* fill the kernel */
len = self->wing_size; len = self->kernel_length;
GST_DEBUG ("lpwsinc: initializing filter kernel of length %d", len * 2 + 1); GST_DEBUG ("lpwsinc: initializing filter kernel of length %d", len);
if (GST_AUDIO_FILTER (self)->format.rate == 0) { if (GST_AUDIO_FILTER (self)->format.rate == 0) {
GST_DEBUG ("rate not set yet"); GST_DEBUG ("rate not set yet");
@ -318,40 +318,40 @@ lpwsinc_build_kernel (GstLPWSinc * self)
if (self->kernel) if (self->kernel)
g_free (self->kernel); g_free (self->kernel);
self->kernel = g_new (gdouble, 2 * len + 1); self->kernel = g_new (gdouble, len);
for (i = 0; i <= len * 2; ++i) { for (i = 0; i < len; ++i) {
if (i == len) if (i == len / 2)
self->kernel[i] = w; self->kernel[i] = w;
else else
self->kernel[i] = sin (w * (i - len)) / (i - len); self->kernel[i] = sin (w * (i - len / 2)) / (i - len / 2);
/* windowing */ /* windowing */
if (self->window == WINDOW_HAMMING) if (self->window == WINDOW_HAMMING)
self->kernel[i] *= (0.54 - 0.46 * cos (M_PI * i / len)); self->kernel[i] *= (0.54 - 0.46 * cos (2 * M_PI * i / len));
else else
self->kernel[i] *= self->kernel[i] *=
(0.42 - 0.5 * cos (M_PI * i / len) + 0.08 * cos (2 * M_PI * i / len)); (0.42 - 0.5 * cos (2 * M_PI * i / len) +
0.08 * cos (4 * M_PI * i / len));
} }
/* normalize for unity gain at DC */ /* normalize for unity gain at DC */
for (i = 0; i <= len * 2; ++i) for (i = 0; i < len; ++i)
sum += self->kernel[i]; sum += self->kernel[i];
for (i = 0; i <= len * 2; ++i) for (i = 0; i < len; ++i)
self->kernel[i] /= sum; self->kernel[i] /= sum;
/* convert to highpass if specified */ /* convert to highpass if specified */
if (self->mode == MODE_HIGH_PASS) { if (self->mode == MODE_HIGH_PASS) {
for (i = 0; i <= len * 2; ++i) for (i = 0; i < len; ++i)
self->kernel[i] = -self->kernel[i]; self->kernel[i] = -self->kernel[i];
self->kernel[len] += 1.0; self->kernel[len / 2] += 1.0;
} }
/* set up the residue memory space */ /* set up the residue memory space */
if (self->residue) if (self->residue)
g_free (self->residue); g_free (self->residue);
self->residue = self->residue =
g_new0 (gdouble, g_new0 (gdouble, len * GST_AUDIO_FILTER (self)->format.channels);
(len * 2 + 1) * GST_AUDIO_FILTER (self)->format.channels);
self->have_kernel = TRUE; self->have_kernel = TRUE;
} }
@ -434,12 +434,18 @@ lpwsinc_set_property (GObject * object, guint prop_id, const GValue * value,
g_return_if_fail (GST_IS_LPWSINC (self)); g_return_if_fail (GST_IS_LPWSINC (self));
switch (prop_id) { switch (prop_id) {
case PROP_LENGTH: case PROP_LENGTH:{
gint val;
GST_BASE_TRANSFORM_LOCK (self); GST_BASE_TRANSFORM_LOCK (self);
self->wing_size = g_value_get_int (value); val = g_value_get_int (value);
if (val % 2 == 0)
val++;
self->kernel_length = val;
lpwsinc_build_kernel (self); lpwsinc_build_kernel (self);
GST_BASE_TRANSFORM_UNLOCK (self); GST_BASE_TRANSFORM_UNLOCK (self);
break; break;
}
case PROP_FREQUENCY: case PROP_FREQUENCY:
GST_BASE_TRANSFORM_LOCK (self); GST_BASE_TRANSFORM_LOCK (self);
self->frequency = g_value_get_double (value); self->frequency = g_value_get_double (value);
@ -472,7 +478,7 @@ lpwsinc_get_property (GObject * object, guint prop_id, GValue * value,
switch (prop_id) { switch (prop_id) {
case PROP_LENGTH: case PROP_LENGTH:
g_value_set_int (value, self->wing_size); g_value_set_int (value, self->kernel_length);
break; break;
case PROP_FREQUENCY: case PROP_FREQUENCY:
g_value_set_double (value, self->frequency); g_value_set_double (value, self->frequency);

7
gst/filter/gstlpwsinc.h
View file

@ -25,10 +25,6 @@
* chapter 16 * chapter 16
* available at http://www.dspguide.com/ * available at http://www.dspguide.com/
* *
* FIXME:
* - this filter is totally unoptimized !
* - we do not destroy the allocated memory for filters and residue
* - this might be improved upon with bytestream
*/ */
#ifndef __GST_LPWSINC_H__ #ifndef __GST_LPWSINC_H__
@ -69,8 +65,7 @@ struct _GstLPWSinc {
gint mode; gint mode;
gint window; gint window;
gdouble frequency; gdouble frequency;
gint wing_size; /* length of a "wing" of the filter; gint kernel_length; /* length of the filter kernel */
actual length is 2 * wing_size + 1 */
gdouble *residue; /* buffer for left-over samples from previous buffer */ gdouble *residue; /* buffer for left-over samples from previous buffer */
gdouble *kernel; /* filter kernel */ gdouble *kernel; /* filter kernel */