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- #!/usr/bin/python2.5
- #
- # Copyright 2014 Olivier Gillet.
- #
- # Author: Olivier Gillet (ol.gillet@gmail.com)
- #
- # Permission is hereby granted, free of charge, to any person obtaining a copy
- # of this software and associated documentation files (the "Software"), to deal
- # in the Software without restriction, including without limitation the rights
- # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- # copies of the Software, and to permit persons to whom the Software is
- # furnished to do so, subject to the following conditions:
- #
- # The above copyright notice and this permission notice shall be included in
- # all copies or substantial portions of the Software.
- #
- # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- # THE SOFTWARE.
- #
- # See http://creativecommons.org/licenses/MIT/ for more information.
- #
- # -----------------------------------------------------------------------------
- #
- # Lookup table definitions.
-
- import numpy
-
- sample_rate = 48000.0
- lookup_tables = []
- lookup_tables_32 = []
-
- excursion = float(1 << 32)
-
- a4_midi = 69
- a4_pitch = 440.0
- notes = numpy.arange(0 * 128.0, 12 * 128.0 + 16, 16) / 128.0
- pitches = a4_pitch * 2 ** ((notes - a4_midi) / 12)
- increments = excursion / sample_rate * pitches
-
- lookup_tables_32.append(
- ('increments', increments.astype(int)))
-
-
- """----------------------------------------------------------------------------
- Filter coefficients
- ----------------------------------------------------------------------------"""
-
- cutoff = 440.0 * 2 ** ((numpy.arange(-256, 257) - 69) / 12.0)
- f = cutoff / sample_rate
- f[f > 0.5] = 0.5
- f = 2 * numpy.pi * f
- f = 1 - numpy.exp(-numpy.arccosh(2 - numpy.cos(f)))
- lookup_tables_32.append(
- ('cutoff', numpy.maximum(1, f * 32767.0 * 65536.0))
- )
-
-
- """----------------------------------------------------------------------------
- Attenuverter curve
- ----------------------------------------------------------------------------"""
-
- ATTENUVERTER_CURVE_SIZE = 256
-
- x = numpy.arange(0, ATTENUVERTER_CURVE_SIZE + 1) / float(ATTENUVERTER_CURVE_SIZE)
- x[-1] = x[-2]
- x = x * 1.05 - 0.05
- x = (x + numpy.abs(x)) / 2.0
- x_cosine = (1.0 - numpy.cos((x ** 1.5) * numpy.pi)) / 2.0
- x_power = x ** 2.0
- attenuverter_curve = (x_cosine + 0.5 * x_power) / 1.5
- lookup_tables.append(
- ('attenuverter_curve', numpy.round(65535 * attenuverter_curve)))
-
-
-
- """----------------------------------------------------------------------------
- Slope compression table (give more resolution in the edges)
- ----------------------------------------------------------------------------"""
-
- SLOPE_COMPRESSION_SIZE = 256
-
- x = numpy.arange(0, SLOPE_COMPRESSION_SIZE + 1) / (SLOPE_COMPRESSION_SIZE / 2.0)
- x -= 1.0
- sine = numpy.sin(x * numpy.pi / 2)
- lookup_tables.append(('slope_compression', numpy.round(32767.5 * (sine + 1.0))))
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