tonegenerator.cpp Example File

multimedia/spectrum/app/tonegenerator.cpp
/**************************************************************************** ** ** Copyright (C) 2017 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/
#include "spectrum.h" #include "utils.h" #include <QByteArray> #include <QAudioFormat> #include <qmath.h> #include <qendian.h> void generateTone(const SweptTone &tone, const QAudioFormat &format, QByteArray &buffer) { Q_ASSERT(isPCMS16LE(format)); const int channelBytes = format.sampleSize() / 8; const int sampleBytes = format.channelCount() * channelBytes; int length = buffer.size(); const int numSamples = buffer.size() / sampleBytes; Q_ASSERT(length % sampleBytes == 0); Q_UNUSED(sampleBytes) // suppress warning in release builds unsigned char *ptr = reinterpret_cast<unsigned char *>(buffer.data()); qreal phase = 0.0; const qreal d = 2 * M_PI / format.sampleRate(); // We can't generate a zero-frequency sine wave const qreal startFreq = tone.startFreq ? tone.startFreq : 1.0; // Amount by which phase increases on each sample qreal phaseStep = d * startFreq; // Amount by which phaseStep increases on each sample // If this is non-zero, the output is a frequency-swept tone const qreal phaseStepStep = d * (tone.endFreq - startFreq) / numSamples; while (length) { const qreal x = tone.amplitude * qSin(phase); const qint16 value = realToPcm(x); for (int i=0; i<format.channelCount(); ++i) { qToLittleEndian<qint16>(value, ptr); ptr += channelBytes; length -= channelBytes; } phase += phaseStep; while (phase > 2 * M_PI) phase -= 2 * M_PI; phaseStep += phaseStepStep; } }