From efea15c44cf2e56a20964434672e50aeb4c49b02 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= Date: Sun, 19 Aug 2007 19:16:33 +0000 Subject: [PATCH] gst/filter/: Add small comparision with the chebyshev filters in the docs. Original commit message from CVS: * gst/filter/gstbpwsinc.c: * gst/filter/gstlpwsinc.c: Add small comparision with the chebyshev filters in the docs. --- ChangeLog | 6 ++++++ gst/filter/gstbpwsinc.c | 5 +++++ gst/filter/gstlpwsinc.c | 7 +++++-- 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index 8040d03..4fcb0f4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ 2007-08-19 Sebastian Dröge + * gst/filter/gstbpwsinc.c: + * gst/filter/gstlpwsinc.c: + Add small comparision with the chebyshev filters in the docs. + +2007-08-19 Sebastian Dröge + * tests/check/elements/bpwsinc.c: (GST_START_TEST), (bpwsinc_suite): * tests/check/elements/lpwsinc.c: (GST_START_TEST), diff --git a/gst/filter/gstbpwsinc.c b/gst/filter/gstbpwsinc.c index 79fa39d..bf399cb 100644 --- a/gst/filter/gstbpwsinc.c +++ b/gst/filter/gstbpwsinc.c @@ -46,6 +46,11 @@ * controls rolloff and stopband attenuation. The Hamming window provides a faster rolloff but a bit * worse stopband attenuation, the other way around for the Blackman window. * + * + * This element has the advantage over the Chebyshev bandpass and bandreject filter that it has + * a much better rolloff when using a larger kernel size and almost linear phase. The only + * disadvantage is the much slower execution time with larger kernels. + * * Example launch line * * diff --git a/gst/filter/gstlpwsinc.c b/gst/filter/gstlpwsinc.c index 3cf14e5..0db1a74 100644 --- a/gst/filter/gstlpwsinc.c +++ b/gst/filter/gstlpwsinc.c @@ -31,8 +31,6 @@ * is probably the bottleneck * - Maybe allow cascading the filter to get a better stopband attenuation. * Can be done by convolving a filter kernel with itself - * - Drop the first kernel_length/2 samples and append the same number of - * samples on EOS as the first few samples are essentialy zero. */ /** @@ -46,6 +44,11 @@ * controls rolloff and stopband attenuation. The Hamming window provides a faster rolloff but a bit * worse stopband attenuation, the other way around for the Blackman window. * + * + * This element has the advantage over the Chebyshev lowpass and highpass filter that it has + * a much better rolloff when using a larger kernel size and almost linear phase. The only + * disadvantage is the much slower execution time with larger kernels. + * * Example launch line * * -- 2.7.4