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58 lines
No EOL
1.9 KiB
Python
58 lines
No EOL
1.9 KiB
Python
"""
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/* Copyright (c) 2023 Amazon
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Written by Jan Buethe */
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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"""
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import math as m
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import torch
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def ulaw2lin(u):
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scale_1 = 32768.0 / 255.0
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u = u - 128
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s = torch.sign(u)
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u = torch.abs(u)
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return s * scale_1 * (torch.exp(u / 128. * m.log(256)) - 1)
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def lin2ulawq(x):
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scale = 255.0 / 32768.0
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s = torch.sign(x)
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x = torch.abs(x)
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u = s * (128 * torch.log(1 + scale * x) / m.log(256))
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u = torch.clip(128 + torch.round(u), 0, 255)
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return u
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def lin2ulaw(x):
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scale = 255.0 / 32768.0
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s = torch.sign(x)
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x = torch.abs(x)
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u = s * (128 * torch.log(1 + scale * x) / torch.log(256))
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u = torch.clip(128 + u, 0, 255)
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return u |