Mercurial > octave
view scripts/audio/lin2mu.m @ 31551:fd29c7a50a78 stable
maint: use commas, semicolons consistently with Octave conventions.
* makeValidName.m: Remove %!test and move BIST %!asserts to column 1.
* base64decode.m, base64encode.m, which.m, logm.m, uniquetol.m, perms.m:
Delete semicolon (';') at end of %!assert BIST.
* lin2mu.m, interp2.m, interpn.m, lsqnonneg.m, pqpnonneg.m, uniquetol.m,
betainc.m, normalize.m: Add semicolon (';') to end of assert statement within
%!test BIST.
* __memoize__.m, tar_is_bsd.m, publish.m: Add semicolon (';') to line with
keyword "persistent".
* stft.m: Use comma (',') after "case" keyword when code immediately follows.
* gallery.m: Align commas used in case statements in massive switch block.
Remove unnecessary parentheses around a numeric case argument.
* ranks.m: Remove semicolon (';') from case statemnt argument.
author | Rik <rik@octave.org> |
---|---|
date | Sat, 26 Nov 2022 06:32:08 -0800 |
parents | 13a7af4ca0da |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 1995-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## This file is part of Octave. ## ## Octave 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, either version 3 of the License, or ## (at your option) any later version. ## ## Octave 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 Octave; see the file COPYING. If not, see ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{y} =} lin2mu (@var{x}) ## @deftypefnx {} {@var{y} =} lin2mu (@var{x}, @var{n}) ## Convert audio data from linear to mu-law. ## ## Linear values use floating point values in the range -1 @leq{} @var{x} ## @leq{} 1 if @var{n} is 0 (default), or @var{n}-bit signed integers if @var{n} ## is 8 or 16. Mu-law values are 8-bit unsigned integers in the range ## 0 @leq{} @var{y} @leq{} 255. ## @seealso{mu2lin} ## @end deftypefn function y = lin2mu (x, n = 0) if (nargin < 1) print_usage (); endif ## Convert to floating point integers per Matlab. x = double (x); if (nargin == 2) if (! isscalar (n) && ! isreal (n) || (n != 0 && n != 8 && n != 16)) error ("lin2mu: N must be either 0, 8, or 16"); elseif (isempty (n)) n = 0; endif endif ## Transform real and n-bit format to 16-bit. if (n == 0) ## [-1,1] -> [-32768, 32768] x *= 32768; elseif (n != 16) x *= 256; endif ## Determine sign of x, set sign(0) = 1. sig = sign (x) + (x == 0); ## Take absolute value of x, but force it to be smaller than 32636; ## add bias. x = min (abs (x), 32635) + 132; ## Find exponent and fraction of binary representation. [f, e] = log2 (x); y = 64 * sig - 16 * e - fix (32 * f) + 335; endfunction ## Test functionality %!test %! x = -1:1; %! y = x'; %! assert (lin2mu (x), (lin2mu (y))'); %! assert (lin2mu (x), [0, 255, 128]); %!assert (lin2mu ([0, 1, NaN, inf, -inf], 8), [255, 231, NaN, 128, 0]) %!assert (lin2mu ([]), []) %!assert (lin2mu (0), 255) %!assert (lin2mu (0, 0), 255) %!assert (lin2mu (0, 8), 255) %!assert (lin2mu (0, 16), 255) %!assert (lin2mu (2, 8), 219) %!assert (lin2mu (3, []), 128) %!assert (lin2mu (3, 16), 255) %!assert (lin2mu (repmat (-0.23, 1, 1000), 0), repmat (34, 1, 1000)) %!assert (lin2mu (ones (2, 2), 0), repmat (128, 2)) ## Test input validation %!error <Invalid call> lin2mu () %!error <N must be either 0, 8, or 16> lin2mu (1, 2) %!error <N must be either 0, 8, or 16> lin2mu (1, [1,2]) %!error <N must be either 0, 8, or 16> lin2mu (1, ones (1, 2)) %!error <invalid conversion> lin2mu ({2:5})