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// Copyright (C) 2015 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\example spectrum
\title Spectrum Example
\ingroup multimedia_examples
\examplecategory {Multimedia}
\brief Analyzing a raw audio stream using the FFTReal library.
\e Spectrum demonstrates how the \l{Qt Multimedia} module can be used to
analyze an audio stream while recording it, and also play the recorded
stream.
\image spectrum-demo.png
Because Qt Multimedia allows the application to access the raw audio
stream, the data can either be inspected or modified by the application.
The Spectrum Analyzer example displays three pieces of information while
audio is being either captured or played back:
\list
\li Information about the raw audio stream, shown in the uppermost widget:
\list
\li The amount of data currently in the buffer, shown in blue
\li The segment of data which was most recently analysed to compute
the frequency spectrum, shown in green
\li The raw audio waveform, shown in white and scrolling from right to
left
\endlist
\li A representation of the frequency spectrum, shown at the lower left
\li The current RMS level of the audio stream, and the recent 'high
watermark' level, shown at the lower right
\endlist
Spectrum analysis is performed by calculating the Fast Fourier Transform
(FFT) of a segment of audio data. An open-source library,
\l{http://ldesoras.free.fr/prod.html}{FFTReal} is used to compute the
transform. FFTReal is available under the GNU Library General Public License
2.0 or later.
\include examples-run.qdocinc
*/
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