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Test: Cmocka: Add test vector generator for A-law and mu-law
This patch adds Octave script to generate test data for A-law and mu-law coding. Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
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‎test/cmocka/m/export_headerfile_open.m‎

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% SPDX-License-Identifier: BSD-3-Clause
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%
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% Copyright(c) 2022 Intel Corporation. All rights reserved.
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% Copyright(c) 2022-2025 Intel Corporation.
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function fh = export_headerfile_open(headerfn, corp)
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end
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fprintf(fh, '/* SPDX-License-Identifier: BSD-3-Clause\n');
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fprintf(fh, ' *\n');
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fprintf(fh, ' * Copyright(c) %s %s. All rights reserved.\n', ...
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fprintf(fh, ' * Copyright(c) %s %s.\n', ...
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datestr(now, 'yyyy'), corp);
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fprintf(fh, ' */\n\n');
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end

‎test/cmocka/src/math/arithmetic/a_law_mu_law_test_vectors.m‎

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% a_law_mu_law_test_vectors() - Create A-law and mu-law test vectors
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%
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% Running this script creates header files ref_chirp_mono_8k_s16.h,
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% a_law_codec.h, and mu_law_codec.h. The chirp waveform for test
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% input is created with sox, and then ended and decoded as
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% A-law and mu-law.
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% SPDX-License-Identifier: BSD-3-Clause
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%
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% Copyright(c) 2025 Intel Corporation.
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function a_law_mu_law_test_vectors()
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sox = 0;
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alaw = 1;
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mulaw = 1;
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bits = 16;
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ts = 0.5;
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fs = 8e3;
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t = (0:round(ts*fs - 1))/fs;
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x = round(2^(bits - 1) * chirp(t, 100, ts, 3.5e3, 'logarithmic'));
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xmax = 2^(bits - 1) - 1;
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xmin = -2^(bits - 1);
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x = max(min(x, xmax), xmin);
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ref_s16_data = int16(x);
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ref_s16_header_fn = 'ref_chirp_mono_8k_s16.h';
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ref_alaw_header_fn = 'a_law_codec.h';
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ref_mulaw_header_fn = 'mu_law_codec.h';
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close all;
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path(path(), '../../../m');
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if sox
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ref_s16 = '/tmp/chirp_mono_8k_s16.raw';
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ref_alaw_enc = '/tmp/ref_alaw_enc.raw';
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ref_alaw_dec = '/tmp/ref_alaw_dec.raw';
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ref_mulaw_enc = '/tmp/ref_mulaw_enc.raw';
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ref_mulaw_dec = '/tmp/ref_mulaw_dec.raw';
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sox_s16_chirp_gen = sprintf('sox -c 1 -r 8000 -b 16 --encoding signed-integer -n %s synth 0.5 sine 100-3500', ref_s16);
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sox_alaw_enc = sprintf('sox -c 1 -r 8000 -b 16 --encoding signed-integer %s --encoding a-law %s', ref_s16, ref_alaw_enc);
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sox_alaw_dec = sprintf('sox -c 1 -r 8000 --encoding a-law %s -b 16 --encoding signed-integer %s', ref_alaw_enc, ref_alaw_dec);
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sox_mulaw_enc = sprintf('sox -c 1 -r 8000 -b 16 --encoding signed-integer %s --encoding a-law %s', ref_s16, ref_mulaw_enc);
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sox_mulaw_dec = sprintf('sox -c 1 -r 8000 --encoding a-law %s -b 16 --encoding signed-integer %s', ref_mulaw_enc, ref_mulaw_dec);
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system(sox_s16_chirp_gen);
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system(sox_alaw_enc);
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system(sox_alaw_dec);
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system(sox_mulaw_enc);
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system(sox_mulaw_dec);
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ref_s16_data = readbin(ref_s16, 'int16'); figure;
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ref_alaw_enc_data = readbin(ref_alaw_enc, 'uint8');
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ref_alaw_dec_data = readbin(ref_alaw_dec, 'int16');
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ref_mulaw_enc_data = readbin(ref_mulaw_enc, 'uint8');
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ref_mulaw_dec_data = readbin(ref_mulaw_dec, 'int16');
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else
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if alaw
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ref_alaw_enc_data = alaw_enc(ref_s16_data);
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ref_alaw_dec_data = alaw_dec(ref_alaw_enc_data);
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end
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if mulaw
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ref_mulaw_enc_data = mulaw_enc(ref_s16_data);
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ref_mulaw_dec_data = mulaw_dec(ref_mulaw_enc_data);
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end
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end
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if alaw
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plot(ref_s16_data); grid on; title('Input s16');
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figure; plot(ref_alaw_enc_data); grid on; title('A-law data');
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figure; plot(ref_alaw_dec_data); grid on; title('A-law decode s16');
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end
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if mulaw
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figure; plot(ref_mulaw_enc_data); grid on; title('mu-law data');
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figure; plot(ref_mulaw_dec_data); grid on; title('mu-law decode s16');
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end
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fh = export_headerfile_open(ref_s16_header_fn);
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comment = sprintf('Created %s with script a_law_mu_law_test_vectors.m %s', ...
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datestr(now, 0), export_get_git_describe());
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export_comment(fh, comment);
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fprintf(fh, '#include <stdint.h>\n');
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export_ndefine(fh, 'REF_DATA_SAMPLE_COUNT', length(ref_s16_data));
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export_vector(fh, 16, 'chirp_mono_8k_s16', ref_s16_data);
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fclose(fh);
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if alaw
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fh = export_headerfile_open(ref_alaw_header_fn);
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comment = sprintf('Created %s with script a_law_mu_law_test_vectors.m %s', ...
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datestr(now, 0), export_get_git_describe());
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export_comment(fh, comment);
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fprintf(fh, '#include <stdint.h>\n');
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export_vector(fh, 8, 'ref_alaw_enc_data', ref_alaw_enc_data);
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export_vector(fh, 16, 'ref_alaw_dec_data', ref_alaw_dec_data);
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fclose(fh);
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end
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if mulaw
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fh = export_headerfile_open(ref_mulaw_header_fn);
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comment = sprintf('Created %s with script a_law_mu_law_test_vectors.m %s', ...
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datestr(now, 0), export_get_git_describe());
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export_comment(fh, comment);
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fprintf(fh, '#include <stdint.h>\n');
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export_vector(fh, 8, 'ref_mulaw_enc_data', ref_mulaw_enc_data);
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export_vector(fh, 16, 'ref_mulaw_dec_data', ref_mulaw_dec_data);
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fclose(fh);
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end
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end
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function x = readbin(fn, itype)
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fh = fopen(fn, 'r');
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if fh == -1
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fprintf(1, 'Could not open file %s.\n', fn);
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error("Failed.");
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end
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x = fread(fh, inf, itype);
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fclose(fh);
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end
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% See G.711 alaw compress from
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% https://www.itu.int/rec/T-REC-G.191/
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function encoded = alaw_enc(input_samples)
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num_samples = length(input_samples);
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in16 = int16(input_samples);
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encoded_samples = uint8(zeros(num_samples, 1));
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for n = 1:num_samples
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if in16(n) < 0
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ix = bitshift(-in16(n) -1, -4); % 1's complement
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else
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ix = bitshift(in16(n), -4);
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end
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if ix > 15
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iexp = 1;
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while (ix > 16 + 15)
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ix = bitshift(ix, -1);
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iexp = iexp + 1;
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end
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ix = ix - 16;
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ix = ix + bitshift(iexp, 4);
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end
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if in16(n) >= 0
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ix = bitor(ix, 128);
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end
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encoded(n) = bitxor(ix, 85);
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end
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end
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% See G.711 alaw expand from
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% https://www.itu.int/rec/T-REC-G.191/
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function samples_s16 = alaw_dec(input_bytes)
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num_samples = length(input_bytes);
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samples_s16 = int16(zeros(num_samples, 1));
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for n = 1:num_samples
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ix = bitxor(int16(input_bytes(n)), 85);
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ix = bitand(ix, 127);
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iexp = bitshift(ix, -4);
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mant = bitand(ix, 15);
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if iexp > 0
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mant = mant + 16;
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end
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mant = bitshift(mant, 4) + 8;
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if iexp > 1
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mant = bitshift(mant, iexp - 1);
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end
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if input_bytes(n) > 127
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samples_s16(n) = mant;
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else
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samples_s16(n) = -mant;
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end
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end
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end
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% See G.711 ulaw compress from
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% https://www.itu.int/rec/T-REC-G.191/
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function encoded = mulaw_enc(input_samples)
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num_samples = length(input_samples);
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in16 = int16(input_samples);
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encoded_samples = uint8(zeros(num_samples, 1));
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for n = 1:num_samples
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if in16(n) < 0
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absno = bitshift(-in16(n) -1, -2) + 33; % 1's complement
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else
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absno = bitshift(in16(n), -2) + 33;
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end
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absno = min(absno, 8191);
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i = bitshift(absno, -6);
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segno = 1;
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while i > 0
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segno = segno + 1;
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i = bitshift(i, -1);
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end
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high_nibble = 8 - segno;
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low_nibble = bitand(bitshift(absno, -segno), 15);
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low_nibble = 15 - low_nibble;
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encoded(n) = bitor(bitshift(high_nibble, 4), low_nibble);
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if in16(n) >= 0
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encoded(n) = bitor(encoded(n), 128);
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end
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end
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end
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% See G.711 alaw expand from
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% https://www.itu.int/rec/T-REC-G.191/
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function samples_s16 = mulaw_dec(input_bytes)
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num_samples = length(input_bytes);
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samples_s16 = int16(zeros(num_samples, 1));
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for n = 1:num_samples
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if input_bytes(n) < 128
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sign = -1;
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else
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sign = 1;
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end
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mantissa = -int16(input_bytes(n)) - 1; % 1's complement
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exponent = bitand(bitshift(mantissa, -4), 7);
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segment = exponent + 1;
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mantissa = bitand(mantissa, 15);
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step = bitshift(4, segment);
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samples_s16(n) = sign * (bitshift(128, exponent) + step * mantissa + step / 2 - 4 * 33);
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end
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end

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