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gst/equalizer/: Allow setting 0 as bandwidth and handle this correctly.

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Original commit message from CVS:
* gst/equalizer/demo.c: (main):
* gst/equalizer/gstiirequalizer.c:
(gst_iir_equalizer_band_class_init), (setup_filter):
Allow setting 0 as bandwidth and handle this correctly.
Also handle a bandwidth of rate/2 properly.
* gst/equalizer/gstiirequalizernbands.c:
(gst_iir_equalizer_nbands_class_init):
Make it possible to generate a N-band equalizer with 1 bands. The
previous limit of 2 was caused by a nowadays replaced calculation
doing a division by zero if number of bands was 1.
This commit is contained in:
Sebastian Dröge 2007-11-03 19:50:11 +00:00
parent 13a9765877
commit 6edf8c4326
3 changed files with 23 additions and 8 deletions
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27
gst/equalizer/gstiirequalizer.c
View file

@ -232,7 +232,7 @@ gst_iir_equalizer_band_class_init (GstIirEqualizerBandClass * klass)
g_object_class_install_property (gobject_class, ARG_BANDWIDTH,
g_param_spec_double ("bandwidth", "bandwidth",
"difference between bandedges in Hz",
1.0, 100000.0, 1.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
0.0, 100000.0, 1.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
}
static void
@ -390,12 +390,26 @@ setup_filter (GstIirEqualizer * equ, GstIirEqualizerBand * band)
else
omega = 2.0 * M_PI * (band->freq / GST_AUDIO_FILTER (equ)->format.rate);
if (band->width / GST_AUDIO_FILTER (equ)->format.rate > 0.5)
bw = M_PI;
else if (band->width <= 1.0)
bw = 2.0 * M_PI * (1.0 / GST_AUDIO_FILTER (equ)->format.rate);
else
if (band->width / GST_AUDIO_FILTER (equ)->format.rate >= 0.5) {
/* If bandwidth == 0.5 the calculation below fails as tan(M_PI/2)
* is undefined. So set the bandwidth to a slightly smaller value.
*/
bw = M_PI - 0.00000001;
} else if (band->width <= 0.0) {
/* If bandwidth == 0 this band won't change anything so set
* the coefficients accordingly. The coefficient calculation
* below would create coefficients that for some reason amplify
* the band.
*/
band->a0 = 1.0;
band->a1 = 0.0;
band->a2 = 0.0;
band->b1 = 0.0;
band->b2 = 0.0;
goto out;
} else {
bw = 2.0 * M_PI * (band->width / GST_AUDIO_FILTER (equ)->format.rate);
}
edge_gain = sqrt (gain);
gamma = tan (bw / 2.0);
@ -409,6 +423,7 @@ setup_filter (GstIirEqualizer * equ, GstIirEqualizerBand * band)
band->b1 = (2.0 * cos (omega)) / (1.0 + beta);
band->b2 = -(1.0 - beta) / (1.0 + beta);
out:
GST_INFO
("gain = %7.5g, , bandwidth= %7.5g, frequency = %7.5g, a0 = %7.5g, a1 = %7.5g, a2=%7.5g b1 = %7.5g, b2 = %7.5g",
band->gain, band->width, band->freq, band->a0, band->a1, band->a2,

2
gst/equalizer/gstiirequalizernbands.c
View file

@ -84,7 +84,7 @@ gst_iir_equalizer_nbands_class_init (GstIirEqualizerNBandsClass * klass)
g_object_class_install_property (gobject_class, ARG_NUM_BANDS,
g_param_spec_uint ("num-bands", "num-bands",
"number of different bands to use", 2, 64, 10,
"number of different bands to use", 1, 64, 10,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
}

2
tests/examples/equalizer/demo.c
View file

@ -208,7 +208,7 @@ main (int argc, char *argv[])
G_CALLBACK (on_gain_changed), (gpointer) band);
gtk_box_pack_start (GTK_BOX (scales_hbox), widget, FALSE, FALSE, 0);
widget = gtk_vscale_new_with_range (1.0, 20000.0, 5.0);
widget = gtk_vscale_new_with_range (0.0, 20000.0, 5.0);
gtk_scale_set_draw_value (GTK_SCALE (widget), TRUE);
gtk_scale_set_value_pos (GTK_SCALE (widget), GTK_POS_TOP);
gtk_range_set_value (GTK_RANGE (widget), bw);