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Diffstat (limited to 'doc/src/demos/spectrum.qdoc')
| -rw-r--r-- | doc/src/demos/spectrum.qdoc | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/doc/src/demos/spectrum.qdoc b/doc/src/demos/spectrum.qdoc index b720ce1..d5a3f85 100644 --- a/doc/src/demos/spectrum.qdoc +++ b/doc/src/demos/spectrum.qdoc @@ -28,8 +28,34 @@ /*! \example demos/spectrum \title Spectrum Analyzer -This application is a demo which uses the QtMultimedia APIs to capture and -play back PCM audio. While either recording or playback is ongoing, the -application performs real-time level and frequency spectrum analysis, -displaying the results in its main window. + + The Spectrum Analyzer demo shows how the \l{QtMultimedia Module} can be + used in Qt applications to capture and then play back an audio stream. + + \image spectrum-demo.png + + Because QtMultimedia allows the application to access the raw audio + stream, the data can either be inspected or modified by the application. + The Spectrum Analyzer demo displays three pieces of information while + audio is being either captured or played back: + + \list + \o Information about the raw audio stream, shown in the uppermost widget: + \list + \o The amount of data currently in the buffer, shown in blue + \o The segment of data which was most recently analysed to compute + the frequency spectrum, shown in green + \o The raw audio waveform, shown in white and scrolling from right to + left + \endlist + \o A representation of the frequency spectrum, shown at the lower left + \o 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}, against which the + application is dynamically linked, is used to compute the transform. */ + |