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<h1 class="title">engine.h Example File</h1>
<span class="subtitle">multimedia/spectrum/app/engine.h</span>
<!-- $$$multimedia/spectrum/app/engine.h-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">
<span class="comment">/****************************************************************************
**
** 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#ifndef ENGINE_H</span>
<span class="preprocessor">#define ENGINE_H</span>
<span class="preprocessor">#include "spectrum.h"</span>
<span class="preprocessor">#include "spectrumanalyser.h"</span>
<span class="preprocessor">#include "wavfile.h"</span>
<span class="preprocessor">#include <QAudioDeviceInfo></span>
<span class="preprocessor">#include <QAudioFormat></span>
<span class="preprocessor">#include <QBuffer></span>
<span class="preprocessor">#include <QByteArray></span>
<span class="preprocessor">#include <QDir></span>
<span class="preprocessor">#include <QObject></span>
<span class="preprocessor">#include <QVector></span>
<span class="preprocessor">#ifdef DUMP_CAPTURED_AUDIO</span>
<span class="preprocessor">#define DUMP_DATA</span>
<span class="preprocessor">#endif</span>
<span class="preprocessor">#ifdef DUMP_SPECTRUM</span>
<span class="preprocessor">#define DUMP_DATA</span>
<span class="preprocessor">#endif</span>
<span class="keyword">class</span> FrequencySpectrum;
<span class="keyword">class</span> <span class="type"><a href="qaudioinput.html">QAudioInput</a></span>;
<span class="keyword">class</span> <span class="type"><a href="qaudiooutput.html">QAudioOutput</a></span>;
<span class="comment">/**
* This class interfaces with the Qt Multimedia audio classes, and also with
* the SpectrumAnalyser class. Its role is to manage the capture and playback
* of audio data, meanwhile performing real-time analysis of the audio level
* and frequency spectrum.
*/</span>
<span class="keyword">class</span> Engine : <span class="keyword">public</span> <span class="type">QObject</span>
{
Q_OBJECT
<span class="keyword">public</span>:
<span class="keyword">explicit</span> Engine(<span class="type">QObject</span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="operator">~</span>Engine();
<span class="keyword">const</span> <span class="type">QList</span><span class="operator"><</span><span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">></span> <span class="operator">&</span>availableAudioInputDevices() <span class="keyword">const</span>
{ <span class="keyword">return</span> m_availableAudioInputDevices; }
<span class="keyword">const</span> <span class="type">QList</span><span class="operator"><</span><span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">></span> <span class="operator">&</span>availableAudioOutputDevices() <span class="keyword">const</span>
{ <span class="keyword">return</span> m_availableAudioOutputDevices; }
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>Mode mode() <span class="keyword">const</span> { <span class="keyword">return</span> m_mode; }
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State state() <span class="keyword">const</span> { <span class="keyword">return</span> m_state; }
<span class="comment">/**
* \return Current audio format
* \note May be QAudioFormat() if engine is not initialized
*/</span>
<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">&</span> format() <span class="keyword">const</span> { <span class="keyword">return</span> m_format; }
<span class="comment">/**
* Stop any ongoing recording or playback, and reset to ground state.
*/</span>
<span class="type">void</span> reset();
<span class="comment">/**
* Load data from WAV file
*/</span>
bool loadFile(<span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span>fileName);
<span class="comment">/**
* Generate tone
*/</span>
bool generateTone(<span class="keyword">const</span> Tone <span class="operator">&</span>tone);
<span class="comment">/**
* Generate tone
*/</span>
bool generateSweptTone(<span class="type">qreal</span> amplitude);
<span class="comment">/**
* Initialize for recording
*/</span>
bool initializeRecord();
<span class="comment">/**
* Position of the audio input device.
* \return Position in bytes.
*/</span>
<span class="type">qint64</span> recordPosition() <span class="keyword">const</span> { <span class="keyword">return</span> m_recordPosition; }
<span class="comment">/**
* RMS level of the most recently processed set of audio samples.
* \return Level in range (0.0, 1.0)
*/</span>
<span class="type">qreal</span> rmsLevel() <span class="keyword">const</span> { <span class="keyword">return</span> m_rmsLevel; }
<span class="comment">/**
* Peak level of the most recently processed set of audio samples.
* \return Level in range (0.0, 1.0)
*/</span>
<span class="type">qreal</span> peakLevel() <span class="keyword">const</span> { <span class="keyword">return</span> m_peakLevel; }
<span class="comment">/**
* Position of the audio output device.
* \return Position in bytes.
*/</span>
<span class="type">qint64</span> playPosition() <span class="keyword">const</span> { <span class="keyword">return</span> m_playPosition; }
<span class="comment">/**
* Length of the internal engine buffer.
* \return Buffer length in bytes.
*/</span>
<span class="type">qint64</span> bufferLength() <span class="keyword">const</span>;
<span class="comment">/**
* Amount of data held in the buffer.
* \return Data length in bytes.
*/</span>
<span class="type">qint64</span> dataLength() <span class="keyword">const</span> { <span class="keyword">return</span> m_dataLength; }
<span class="comment">/**
* Set window function applied to audio data before spectral analysis.
*/</span>
<span class="type">void</span> setWindowFunction(WindowFunction type);
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> startRecording();
<span class="type">void</span> startPlayback();
<span class="type">void</span> suspend();
<span class="type">void</span> setAudioInputDevice(<span class="keyword">const</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> <span class="operator">&</span>device);
<span class="type">void</span> setAudioOutputDevice(<span class="keyword">const</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> <span class="operator">&</span>device);
<span class="keyword">signals</span>:
<span class="type">void</span> stateChanged(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>Mode mode<span class="operator">,</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State state);
<span class="comment">/**
* Informational message for non-modal display
*/</span>
<span class="type">void</span> infoMessage(<span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span>message<span class="operator">,</span> <span class="type">int</span> durationMs);
<span class="comment">/**
* Error message for modal display
*/</span>
<span class="type">void</span> errorMessage(<span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span>heading<span class="operator">,</span> <span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span>detail);
<span class="comment">/**
* Format of audio data has changed
*/</span>
<span class="type">void</span> formatChanged(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&</span>format);
<span class="comment">/**
* Length of buffer has changed.
* \param duration Duration in microseconds
*/</span>
<span class="type">void</span> bufferLengthChanged(<span class="type">qint64</span> duration);
<span class="comment">/**
* Amount of data in buffer has changed.
* \param Length of data in bytes
*/</span>
<span class="type">void</span> dataLengthChanged(<span class="type">qint64</span> duration);
<span class="comment">/**
* Position of the audio input device has changed.
* \param position Position in bytes
*/</span>
<span class="type">void</span> recordPositionChanged(<span class="type">qint64</span> position);
<span class="comment">/**
* Position of the audio output device has changed.
* \param position Position in bytes
*/</span>
<span class="type">void</span> playPositionChanged(<span class="type">qint64</span> position);
<span class="comment">/**
* Level changed
* \param rmsLevel RMS level in range 0.0 - 1.0
* \param peakLevel Peak level in range 0.0 - 1.0
* \param numSamples Number of audio samples analyzed
*/</span>
<span class="type">void</span> levelChanged(<span class="type">qreal</span> rmsLevel<span class="operator">,</span> <span class="type">qreal</span> peakLevel<span class="operator">,</span> <span class="type">int</span> numSamples);
<span class="comment">/**
* Spectrum has changed.
* \param position Position of start of window in bytes
* \param length Length of window in bytes
* \param spectrum Resulting frequency spectrum
*/</span>
<span class="type">void</span> spectrumChanged(<span class="type">qint64</span> position<span class="operator">,</span> <span class="type">qint64</span> length<span class="operator">,</span> <span class="keyword">const</span> FrequencySpectrum <span class="operator">&</span>spectrum);
<span class="comment">/**
* Buffer containing audio data has changed.
* \param position Position of start of buffer in bytes
* \param buffer Buffer
*/</span>
<span class="type">void</span> bufferChanged(<span class="type">qint64</span> position<span class="operator">,</span> <span class="type">qint64</span> length<span class="operator">,</span> <span class="keyword">const</span> <span class="type">QByteArray</span> <span class="operator">&</span>buffer);
<span class="keyword">private</span> <span class="keyword">slots</span>:
<span class="type">void</span> audioNotify();
<span class="type">void</span> audioStateChanged(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State state);
<span class="type">void</span> audioDataReady();
<span class="type">void</span> spectrumChanged(<span class="keyword">const</span> FrequencySpectrum <span class="operator">&</span>spectrum);
<span class="keyword">private</span>:
<span class="type">void</span> resetAudioDevices();
bool initialize();
bool selectFormat();
<span class="type">void</span> stopRecording();
<span class="type">void</span> stopPlayback();
<span class="type">void</span> setState(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State state);
<span class="type">void</span> setState(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>Mode mode<span class="operator">,</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State state);
<span class="type">void</span> setFormat(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&</span>format);
<span class="type">void</span> setRecordPosition(<span class="type">qint64</span> position<span class="operator">,</span> bool forceEmit <span class="operator">=</span> <span class="keyword">false</span>);
<span class="type">void</span> setPlayPosition(<span class="type">qint64</span> position<span class="operator">,</span> bool forceEmit <span class="operator">=</span> <span class="keyword">false</span>);
<span class="type">void</span> calculateLevel(<span class="type">qint64</span> position<span class="operator">,</span> <span class="type">qint64</span> length);
<span class="type">void</span> calculateSpectrum(<span class="type">qint64</span> position);
<span class="type">void</span> setLevel(<span class="type">qreal</span> rmsLevel<span class="operator">,</span> <span class="type">qreal</span> peakLevel<span class="operator">,</span> <span class="type">int</span> numSamples);
<span class="preprocessor">#ifdef DUMP_DATA</span>
<span class="type">void</span> createOutputDir();
<span class="type">QString</span> outputPath() <span class="keyword">const</span> { <span class="keyword">return</span> m_outputDir<span class="operator">.</span>path(); }
<span class="preprocessor">#endif</span>
<span class="preprocessor">#ifdef DUMP_CAPTURED_AUDIO</span>
<span class="type">void</span> dumpData();
<span class="preprocessor">#endif</span>
<span class="keyword">private</span>:
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>Mode m_mode;
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State m_state;
bool m_generateTone;
SweptTone m_tone;
WavFile<span class="operator">*</span> m_file;
<span class="comment">// We need a second file handle via which to read data into m_buffer</span>
<span class="comment">// for analysis</span>
WavFile<span class="operator">*</span> m_analysisFile;
<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> m_format;
<span class="keyword">const</span> <span class="type">QList</span><span class="operator"><</span><span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">></span> m_availableAudioInputDevices;
<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> m_audioInputDevice;
<span class="type"><a href="qaudioinput.html">QAudioInput</a></span><span class="operator">*</span> m_audioInput;
<span class="type">QIODevice</span><span class="operator">*</span> m_audioInputIODevice;
<span class="type">qint64</span> m_recordPosition;
<span class="keyword">const</span> <span class="type">QList</span><span class="operator"><</span><span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">></span> m_availableAudioOutputDevices;
<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> m_audioOutputDevice;
<span class="type"><a href="qaudiooutput.html">QAudioOutput</a></span><span class="operator">*</span> m_audioOutput;
<span class="type">QString</span> m_audioOutputCategory;
<span class="type">qint64</span> m_playPosition;
<span class="type">QBuffer</span> m_audioOutputIODevice;
<span class="type">QByteArray</span> m_buffer;
<span class="type">qint64</span> m_bufferPosition;
<span class="type">qint64</span> m_bufferLength;
<span class="type">qint64</span> m_dataLength;
<span class="type">int</span> m_levelBufferLength;
<span class="type">qreal</span> m_rmsLevel;
<span class="type">qreal</span> m_peakLevel;
<span class="type">int</span> m_spectrumBufferLength;
<span class="type">QByteArray</span> m_spectrumBuffer;
SpectrumAnalyser m_spectrumAnalyser;
<span class="type">qint64</span> m_spectrumPosition;
<span class="type">int</span> m_count;
<span class="preprocessor">#ifdef DUMP_DATA</span>
<span class="type">QDir</span> m_outputDir;
<span class="preprocessor">#endif</span>
};
<span class="preprocessor">#endif // ENGINE_H</span>
</pre>
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<!-- @@@multimedia/spectrum/app/engine.h -->
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