554 lines
13 KiB
Python
554 lines
13 KiB
Python
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try:
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from __builtin__ import max as builtin_max
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from __builtin__ import min as builtin_min
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except ImportError:
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from builtins import max as builtin_max
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from builtins import min as builtin_min
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import math
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import struct
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try:
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from fractions import gcd
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except ImportError: # Python 3.9+
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from math import gcd
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from ctypes import create_string_buffer
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class error(Exception):
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pass
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def _check_size(size):
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if size != 1 and size != 2 and size != 4:
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raise error("Size should be 1, 2 or 4")
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def _check_params(length, size):
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_check_size(size)
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if length % size != 0:
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raise error("not a whole number of frames")
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def _sample_count(cp, size):
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return len(cp) / size
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def _get_samples(cp, size, signed=True):
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for i in range(_sample_count(cp, size)):
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yield _get_sample(cp, size, i, signed)
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def _struct_format(size, signed):
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if size == 1:
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return "b" if signed else "B"
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elif size == 2:
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return "h" if signed else "H"
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elif size == 4:
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return "i" if signed else "I"
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def _get_sample(cp, size, i, signed=True):
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fmt = _struct_format(size, signed)
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start = i * size
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end = start + size
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return struct.unpack_from(fmt, buffer(cp)[start:end])[0]
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def _put_sample(cp, size, i, val, signed=True):
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fmt = _struct_format(size, signed)
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struct.pack_into(fmt, cp, i * size, val)
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def _get_maxval(size, signed=True):
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if signed and size == 1:
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return 0x7f
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elif size == 1:
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return 0xff
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elif signed and size == 2:
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return 0x7fff
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elif size == 2:
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return 0xffff
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elif signed and size == 4:
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return 0x7fffffff
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elif size == 4:
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return 0xffffffff
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def _get_minval(size, signed=True):
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if not signed:
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return 0
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elif size == 1:
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return -0x80
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elif size == 2:
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return -0x8000
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elif size == 4:
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return -0x80000000
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def _get_clipfn(size, signed=True):
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maxval = _get_maxval(size, signed)
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minval = _get_minval(size, signed)
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return lambda val: builtin_max(min(val, maxval), minval)
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def _overflow(val, size, signed=True):
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minval = _get_minval(size, signed)
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maxval = _get_maxval(size, signed)
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if minval <= val <= maxval:
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return val
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bits = size * 8
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if signed:
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offset = 2**(bits-1)
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return ((val + offset) % (2**bits)) - offset
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else:
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return val % (2**bits)
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def getsample(cp, size, i):
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_check_params(len(cp), size)
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if not (0 <= i < len(cp) / size):
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raise error("Index out of range")
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return _get_sample(cp, size, i)
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def max(cp, size):
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_check_params(len(cp), size)
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if len(cp) == 0:
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return 0
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return builtin_max(abs(sample) for sample in _get_samples(cp, size))
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def minmax(cp, size):
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_check_params(len(cp), size)
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max_sample, min_sample = 0, 0
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for sample in _get_samples(cp, size):
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max_sample = builtin_max(sample, max_sample)
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min_sample = builtin_min(sample, min_sample)
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return min_sample, max_sample
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def avg(cp, size):
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_check_params(len(cp), size)
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sample_count = _sample_count(cp, size)
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if sample_count == 0:
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return 0
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return sum(_get_samples(cp, size)) / sample_count
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def rms(cp, size):
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_check_params(len(cp), size)
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sample_count = _sample_count(cp, size)
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if sample_count == 0:
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return 0
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sum_squares = sum(sample**2 for sample in _get_samples(cp, size))
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return int(math.sqrt(sum_squares / sample_count))
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def _sum2(cp1, cp2, length):
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size = 2
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total = 0
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for i in range(length):
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total += getsample(cp1, size, i) * getsample(cp2, size, i)
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return total
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def findfit(cp1, cp2):
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size = 2
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if len(cp1) % 2 != 0 or len(cp2) % 2 != 0:
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raise error("Strings should be even-sized")
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if len(cp1) < len(cp2):
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raise error("First sample should be longer")
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len1 = _sample_count(cp1, size)
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len2 = _sample_count(cp2, size)
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sum_ri_2 = _sum2(cp2, cp2, len2)
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sum_aij_2 = _sum2(cp1, cp1, len2)
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sum_aij_ri = _sum2(cp1, cp2, len2)
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result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
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best_result = result
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best_i = 0
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for i in range(1, len1 - len2 + 1):
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aj_m1 = _get_sample(cp1, size, i - 1)
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aj_lm1 = _get_sample(cp1, size, i + len2 - 1)
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sum_aij_2 += aj_lm1**2 - aj_m1**2
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sum_aij_ri = _sum2(buffer(cp1)[i*size:], cp2, len2)
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result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
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if result < best_result:
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best_result = result
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best_i = i
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factor = _sum2(buffer(cp1)[best_i*size:], cp2, len2) / sum_ri_2
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return best_i, factor
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def findfactor(cp1, cp2):
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size = 2
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if len(cp1) % 2 != 0:
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raise error("Strings should be even-sized")
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if len(cp1) != len(cp2):
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raise error("Samples should be same size")
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sample_count = _sample_count(cp1, size)
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sum_ri_2 = _sum2(cp2, cp2, sample_count)
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sum_aij_ri = _sum2(cp1, cp2, sample_count)
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return sum_aij_ri / sum_ri_2
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def findmax(cp, len2):
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size = 2
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sample_count = _sample_count(cp, size)
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if len(cp) % 2 != 0:
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raise error("Strings should be even-sized")
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if len2 < 0 or sample_count < len2:
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raise error("Input sample should be longer")
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if sample_count == 0:
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return 0
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result = _sum2(cp, cp, len2)
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best_result = result
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best_i = 0
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for i in range(1, sample_count - len2 + 1):
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sample_leaving_window = getsample(cp, size, i - 1)
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sample_entering_window = getsample(cp, size, i + len2 - 1)
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result -= sample_leaving_window**2
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result += sample_entering_window**2
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if result > best_result:
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best_result = result
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best_i = i
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return best_i
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def avgpp(cp, size):
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_check_params(len(cp), size)
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sample_count = _sample_count(cp, size)
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prevextremevalid = False
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prevextreme = None
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avg = 0
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nextreme = 0
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prevval = getsample(cp, size, 0)
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val = getsample(cp, size, 1)
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prevdiff = val - prevval
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for i in range(1, sample_count):
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val = getsample(cp, size, i)
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diff = val - prevval
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if diff * prevdiff < 0:
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if prevextremevalid:
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avg += abs(prevval - prevextreme)
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nextreme += 1
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prevextremevalid = True
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prevextreme = prevval
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prevval = val
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if diff != 0:
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prevdiff = diff
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if nextreme == 0:
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return 0
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return avg / nextreme
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def maxpp(cp, size):
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_check_params(len(cp), size)
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sample_count = _sample_count(cp, size)
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prevextremevalid = False
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prevextreme = None
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max = 0
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prevval = getsample(cp, size, 0)
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val = getsample(cp, size, 1)
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prevdiff = val - prevval
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for i in range(1, sample_count):
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val = getsample(cp, size, i)
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diff = val - prevval
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if diff * prevdiff < 0:
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if prevextremevalid:
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extremediff = abs(prevval - prevextreme)
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if extremediff > max:
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max = extremediff
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prevextremevalid = True
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prevextreme = prevval
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prevval = val
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if diff != 0:
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prevdiff = diff
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return max
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def cross(cp, size):
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_check_params(len(cp), size)
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crossings = 0
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last_sample = 0
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for sample in _get_samples(cp, size):
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if sample <= 0 < last_sample or sample >= 0 > last_sample:
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crossings += 1
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last_sample = sample
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return crossings
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def mul(cp, size, factor):
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_check_params(len(cp), size)
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clip = _get_clipfn(size)
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result = create_string_buffer(len(cp))
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for i, sample in enumerate(_get_samples(cp, size)):
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sample = clip(int(sample * factor))
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_put_sample(result, size, i, sample)
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return result.raw
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def tomono(cp, size, fac1, fac2):
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_check_params(len(cp), size)
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clip = _get_clipfn(size)
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sample_count = _sample_count(cp, size)
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result = create_string_buffer(len(cp) / 2)
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for i in range(0, sample_count, 2):
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l_sample = getsample(cp, size, i)
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r_sample = getsample(cp, size, i + 1)
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sample = (l_sample * fac1) + (r_sample * fac2)
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sample = clip(sample)
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_put_sample(result, size, i / 2, sample)
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return result.raw
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def tostereo(cp, size, fac1, fac2):
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_check_params(len(cp), size)
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sample_count = _sample_count(cp, size)
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result = create_string_buffer(len(cp) * 2)
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clip = _get_clipfn(size)
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for i in range(sample_count):
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sample = _get_sample(cp, size, i)
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l_sample = clip(sample * fac1)
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r_sample = clip(sample * fac2)
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_put_sample(result, size, i * 2, l_sample)
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_put_sample(result, size, i * 2 + 1, r_sample)
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return result.raw
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def add(cp1, cp2, size):
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_check_params(len(cp1), size)
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if len(cp1) != len(cp2):
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raise error("Lengths should be the same")
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clip = _get_clipfn(size)
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sample_count = _sample_count(cp1, size)
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result = create_string_buffer(len(cp1))
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for i in range(sample_count):
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sample1 = getsample(cp1, size, i)
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sample2 = getsample(cp2, size, i)
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sample = clip(sample1 + sample2)
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_put_sample(result, size, i, sample)
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return result.raw
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def bias(cp, size, bias):
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_check_params(len(cp), size)
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result = create_string_buffer(len(cp))
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for i, sample in enumerate(_get_samples(cp, size)):
|
||
|
|
sample = _overflow(sample + bias, size)
|
||
|
|
_put_sample(result, size, i, sample)
|
||
|
|
|
||
|
|
return result.raw
|
||
|
|
|
||
|
|
|
||
|
|
def reverse(cp, size):
|
||
|
|
_check_params(len(cp), size)
|
||
|
|
sample_count = _sample_count(cp, size)
|
||
|
|
|
||
|
|
result = create_string_buffer(len(cp))
|
||
|
|
for i, sample in enumerate(_get_samples(cp, size)):
|
||
|
|
_put_sample(result, size, sample_count - i - 1, sample)
|
||
|
|
|
||
|
|
return result.raw
|
||
|
|
|
||
|
|
|
||
|
|
def lin2lin(cp, size, size2):
|
||
|
|
_check_params(len(cp), size)
|
||
|
|
_check_size(size2)
|
||
|
|
|
||
|
|
if size == size2:
|
||
|
|
return cp
|
||
|
|
|
||
|
|
new_len = (len(cp) / size) * size2
|
||
|
|
|
||
|
|
result = create_string_buffer(new_len)
|
||
|
|
|
||
|
|
for i in range(_sample_count(cp, size)):
|
||
|
|
sample = _get_sample(cp, size, i)
|
||
|
|
if size < size2:
|
||
|
|
sample = sample << (4 * size2 / size)
|
||
|
|
elif size > size2:
|
||
|
|
sample = sample >> (4 * size / size2)
|
||
|
|
|
||
|
|
sample = _overflow(sample, size2)
|
||
|
|
|
||
|
|
_put_sample(result, size2, i, sample)
|
||
|
|
|
||
|
|
return result.raw
|
||
|
|
|
||
|
|
|
||
|
|
def ratecv(cp, size, nchannels, inrate, outrate, state, weightA=1, weightB=0):
|
||
|
|
_check_params(len(cp), size)
|
||
|
|
if nchannels < 1:
|
||
|
|
raise error("# of channels should be >= 1")
|
||
|
|
|
||
|
|
bytes_per_frame = size * nchannels
|
||
|
|
frame_count = len(cp) / bytes_per_frame
|
||
|
|
|
||
|
|
if bytes_per_frame / nchannels != size:
|
||
|
|
raise OverflowError("width * nchannels too big for a C int")
|
||
|
|
|
||
|
|
if weightA < 1 or weightB < 0:
|
||
|
|
raise error("weightA should be >= 1, weightB should be >= 0")
|
||
|
|
|
||
|
|
if len(cp) % bytes_per_frame != 0:
|
||
|
|
raise error("not a whole number of frames")
|
||
|
|
|
||
|
|
if inrate <= 0 or outrate <= 0:
|
||
|
|
raise error("sampling rate not > 0")
|
||
|
|
|
||
|
|
d = gcd(inrate, outrate)
|
||
|
|
inrate /= d
|
||
|
|
outrate /= d
|
||
|
|
|
||
|
|
prev_i = [0] * nchannels
|
||
|
|
cur_i = [0] * nchannels
|
||
|
|
|
||
|
|
if state is None:
|
||
|
|
d = -outrate
|
||
|
|
else:
|
||
|
|
d, samps = state
|
||
|
|
|
||
|
|
if len(samps) != nchannels:
|
||
|
|
raise error("illegal state argument")
|
||
|
|
|
||
|
|
prev_i, cur_i = zip(*samps)
|
||
|
|
prev_i, cur_i = list(prev_i), list(cur_i)
|
||
|
|
|
||
|
|
q = frame_count / inrate
|
||
|
|
ceiling = (q + 1) * outrate
|
||
|
|
nbytes = ceiling * bytes_per_frame
|
||
|
|
|
||
|
|
result = create_string_buffer(nbytes)
|
||
|
|
|
||
|
|
samples = _get_samples(cp, size)
|
||
|
|
out_i = 0
|
||
|
|
while True:
|
||
|
|
while d < 0:
|
||
|
|
if frame_count == 0:
|
||
|
|
samps = zip(prev_i, cur_i)
|
||
|
|
retval = result.raw
|
||
|
|
|
||
|
|
# slice off extra bytes
|
||
|
|
trim_index = (out_i * bytes_per_frame) - len(retval)
|
||
|
|
retval = buffer(retval)[:trim_index]
|
||
|
|
|
||
|
|
return (retval, (d, tuple(samps)))
|
||
|
|
|
||
|
|
for chan in range(nchannels):
|
||
|
|
prev_i[chan] = cur_i[chan]
|
||
|
|
cur_i[chan] = samples.next()
|
||
|
|
|
||
|
|
cur_i[chan] = (
|
||
|
|
(weightA * cur_i[chan] + weightB * prev_i[chan])
|
||
|
|
/ (weightA + weightB)
|
||
|
|
)
|
||
|
|
|
||
|
|
frame_count -= 1
|
||
|
|
d += outrate
|
||
|
|
|
||
|
|
while d >= 0:
|
||
|
|
for chan in range(nchannels):
|
||
|
|
cur_o = (
|
||
|
|
(prev_i[chan] * d + cur_i[chan] * (outrate - d))
|
||
|
|
/ outrate
|
||
|
|
)
|
||
|
|
_put_sample(result, size, out_i, _overflow(cur_o, size))
|
||
|
|
out_i += 1
|
||
|
|
d -= inrate
|
||
|
|
|
||
|
|
|
||
|
|
def lin2ulaw(cp, size):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|
||
|
|
|
||
|
|
def ulaw2lin(cp, size):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|
||
|
|
|
||
|
|
def lin2alaw(cp, size):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|
||
|
|
|
||
|
|
def alaw2lin(cp, size):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|
||
|
|
|
||
|
|
def lin2adpcm(cp, size, state):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|
||
|
|
|
||
|
|
def adpcm2lin(cp, size, state):
|
||
|
|
raise NotImplementedError()
|