resample filter: Infrastructure.

[paraslash.git] / m4 / gengetopt / resample_filter.m4

diff --git a/m4/gengetopt/resample_filter.m4 b/m4/gengetopt/resample_filter.m4
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+option "converter" c
+#~~~~~~~~~~~~~~~~~~~
+"choose converter type"
+enum typestr = "type"
+values = "best", "medium", "fastest", "zero_order_hold", "linear"
+default = "medium"
+optional
+
+details = "
+       best: This is a bandlimited interpolator derived from the
+       mathematical sinc function and this is the highest quality
+       sinc based converter, providing a worst case Signal-to-Noise
+       Ratio (SNR) of 97 decibels (dB) at a bandwidth of 97%.
+
+       medium: This is another bandlimited interpolator much like the
+       previous one. It has an SNR of 97dB and a bandwidth of 90%. The
+       speed of the conversion is much faster than the previous one.
+
+       fastest: This is the fastest bandlimited interpolator and
+       has an SNR of 97dB and a bandwidth of 80%.
+
+       zero_order_hold: A Zero Order Hold converter (interpolated
+       value is equal to the last value). The quality is poor but
+       the conversion speed is blindlingly fast.
+
+       linear: A linear converter. Again the quality is poor, but
+       the conversion speed is blindingly fast.
+"