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authorSebastian Dröge <slomo@circular-chaos.org>2007-11-03 19:50:11 +0000
committerSebastian Dröge <slomo@circular-chaos.org>2007-11-03 19:50:11 +0000
commitf627f21233890b35e0420171c67b2b380108da73 (patch)
treecaa05e9b4a6a00f37516cf11678d9902253578ea /gst/equalizer/gstiirequalizer.c
parentc67ad65c91417d171692d34e49e412516895ac3a (diff)
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gst/equalizer/: Allow setting 0 as bandwidth and handle this correctly.
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.
Diffstat (limited to 'gst/equalizer/gstiirequalizer.c')
-rw-r--r--gst/equalizer/gstiirequalizer.c27
1 files changed, 21 insertions, 6 deletions
diff --git a/gst/equalizer/gstiirequalizer.c b/gst/equalizer/gstiirequalizer.c
index 25ee6972..cd955e28 100644
--- a/gst/equalizer/gstiirequalizer.c
+++ b/gst/equalizer/gstiirequalizer.c
@@ -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,