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# This file is part of jack_mixer
#
# Copyright (C) 2006 Nedko Arnaudov <nedko@arnaudov.name>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
import logging
import math
from ._jack_mixer import Scale
log = logging.getLogger(__name__)
class Mark:
"""Encapsulates scale linear function edge and coefficients for scale = a * dB + b formula"""
def __init__(self, db, scale, text=None):
self.db = db
self.scale = scale
if text is None:
# TODO: l10n
self.text = "%.0f" % math.fabs(db)
else:
self.text = text
class Base:
"""Scale abstraction, various scale implementation derive from this class"""
def __init__(self, scale_id, description):
self.marks = []
self.scale_id = scale_id
self.description = description
self.scale = Scale()
def add_threshold(self, db, scale, is_mark, text=None):
self.scale.add_threshold(db, scale)
if is_mark:
self.marks.append(Mark(db, scale, text))
def calculate_coefficients(self):
self.scale.calculate_coefficients()
def db_to_scale(self, db):
"""Convert dBFS value to number in range 0.0-1.0 used in GUI"""
# log.debug("db_to_scale(%f)", db)
return self.scale.db_to_scale(db)
def scale_to_db(self, scale):
"""Convert number in range 0.0-1.0 used in GUI to dBFS value"""
return self.scale.scale_to_db(scale)
def add_mark(self, db):
self.marks.append(Mark(db, -1.0))
def get_marks(self):
return self.marks
def scale_marks(self):
for i in self.marks:
if i.scale == -1.0:
i.scale = self.db_to_scale(i.db)
# IEC 60268-18 Peak programme level meters - Digital audio peak level meter
# Adapted from meterbridge, may be wrong, I'm not buying standards, even if they cost $45
# If someone has the standard, please either share it with me or fix the code.
class IEC268(Base):
"""IEC 60268-18 Peak programme level meters - Digital audio peak level meter"""
def __init__(self):
Base.__init__(
self,
"iec_268",
_("IEC 60268-18 Peak programme level meters - Digital audio peak level meter"),
)
self.add_threshold(-70.0, 0.0, False)
self.add_threshold(-60.0, 0.05, True)
self.add_threshold(-50.0, 0.075, True)
self.add_threshold(-40.0, 0.15, True)
self.add_mark(-35.0)
self.add_threshold(-30.0, 0.3, True)
self.add_mark(-25.0)
self.add_threshold(-20.0, 0.5, True)
self.add_mark(-15.0)
self.add_mark(-10.0)
self.add_mark(-5.0)
self.add_threshold(0.0, 1.0, True)
self.calculate_coefficients()
self.scale_marks()
class IEC268Minimalistic(Base):
"""IEC 60268-18 Peak programme level meters - Digital audio peak level meter,
fewer marks"""
def __init__(self):
Base.__init__(
self,
"iec_268_minimalistic",
_(
"IEC 60268-18 Peak programme level meters - "
"Digital audio peak level meter, fewer marks"
),
)
self.add_threshold(-70.0, 0.0, False)
self.add_threshold(-60.0, 0.05, True)
self.add_threshold(-50.0, 0.075, False)
self.add_threshold(-40.0, 0.15, True)
self.add_threshold(-30.0, 0.3, True)
self.add_threshold(-20.0, 0.5, True)
self.add_mark(-10.0)
self.add_threshold(0.0, 1.0, True)
self.calculate_coefficients()
self.scale_marks()
class Linear70dB(Base):
"""Linear scale with range from -70 to 0 dBFS"""
def __init__(self):
Base.__init__(self, "linear_70dB", _("Linear scale with range from -70 to 0 dBFS"))
self.add_threshold(-70.0, 0.0, False)
self.add_mark(-60.0)
self.add_mark(-50.0)
self.add_mark(-40.0)
self.add_mark(-35.0)
self.add_mark(-30.0)
self.add_mark(-25.0)
self.add_mark(-20.0)
self.add_mark(-15.0)
self.add_mark(-10.0)
self.add_mark(-5.0)
self.add_threshold(0.0, 1.0, True)
self.calculate_coefficients()
self.scale_marks()
class Linear30dB(Base):
"""Linear scale with range from -30 to +30 dBFS"""
def __init__(self):
Base.__init__(self, "linear_30dB", _("Linear scale with range from -30 to +30 dBFS"))
self.add_threshold(-30.0, 0.0, False)
self.add_threshold(+30.0, 1.0, True)
self.calculate_coefficients()
self.scale_marks()
class K20(Base):
"""K20 scale"""
def __init__(self):
Base.__init__(self, "K20", _("K20 scale"))
self.add_mark(-200, "")
self.add_mark(-60, "-40")
self.add_mark(-55, "")
self.add_mark(-50, "-30")
self.add_mark(-45, "")
self.add_mark(-40, "-20")
self.add_mark(-35, "")
self.add_mark(-30, "-10")
self.add_mark(-26, "-6")
self.add_mark(-23, "-3")
self.add_mark(-20, "0")
self.add_mark(-17, "3")
self.add_mark(-14, "6")
self.add_mark(-10, "10")
self.add_mark(-5, "15")
self.add_mark(0, "20")
def db_to_scale(self, db):
v = math.pow(10.0, db / 20.0)
return self.mapk20(v) / 450.0
def add_mark(self, db, text):
self.marks.append(Mark(db, self.db_to_scale(db), text))
def mapk20(self, v):
if v < 0.001:
return 24000 * v
v = math.log10(v) + 3
if v < 2.0:
return 24.3 + v * (100 + v * 16)
if v > 3.0:
v = 3.0
return v * 161.7 - 35.1
class K14(Base):
"""K14 scale"""
def __init__(self):
Base.__init__(self, "K14", _("K14 scale"))
self.add_mark(-200, "")
self.add_mark(-54, "-40")
self.add_mark(-35 - 14, "")
self.add_mark(-30 - 14, "-30")
self.add_mark(-25 - 14, "")
self.add_mark(-20 - 14, "-20")
self.add_mark(-15 - 14, "")
self.add_mark(-10 - 14, "-10")
self.add_mark(-6 - 14, "-6")
self.add_mark(-3 - 14, "-3")
self.add_mark(-14, "0")
self.add_mark(3 - 14, "3")
self.add_mark(6 - 14, "6")
self.add_mark(10 - 14, "10")
self.add_mark(14 - 14, "14")
def db_to_scale(self, db):
v = math.pow(10.0, db / 20.0)
return self.mapk14(v) / 448.3
def add_mark(self, db, text):
self.marks.append(Mark(db, self.db_to_scale(db), text))
def mapk14(self, v):
if v < 0.002:
return int(12000 * v)
v = math.log10(v) + 2.7
if v < 2.0:
return int(20.3 + v * (80 + v * 32))
if v > 2.7:
v = 2.7
return int(v * 200 - 91.7)
def scale_test1(scale):
for i in range(-97 * 2, 1, 1):
db = float(i) / 2.0
print("%5.1f dB maps to %f" % (db, scale.db_to_scale(db)))
def scale_test2(scale):
for i in range(101):
s = float(i) / 100.0
print("%.2f maps to %.1f dB" % (s, scale.scale_to_db(s)))
def print_db_to_scale(scale, db):
print("%-.1f dB maps to %f" % (db, scale.db_to_scale(db)))
def scale_test3(scale):
print_db_to_scale(scale, +77.0)
print_db_to_scale(scale, +7.0)
print_db_to_scale(scale, 0.0)
print_db_to_scale(scale, -107.0)
def _test(*args, **kwargs):
scale = Linear30dB()
scale_test1(scale)
scale_test2(scale)
scale_test3(scale)
if __name__ == "__main__":
_test()
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