c@126: 
c@126: Constant-Q Library
c@126: ==================
c@126: 
c@130: A C++ library and Vamp plugin implementing the Constant-Q transform
c@130: of a time-domain signal.
c@126: 
c@126: https://code.soundsoftware.ac.uk/projects/constant-q-cpp
c@126: 
c@126: The Constant-Q transform is a time-to-frequency-domain transform
c@126: related to the short-time Fourier transform, but with output bins
c@126: spaced logarithmically in frequency, rather than linearly. The output
c@126: bins are therefore linearly spaced in terms of musical pitch.
c@126: 
c@193: This implementation is reasonably fast and is causal, operating
c@193: block-by-block on the input, though with quite high latency depending
c@193: on the frequency range specified. By default it produces output at a
c@193: higher time resolution than some other implementations, using multiple
c@193: kernel atoms per time block. The inverse transform is approximate
c@193: rather than exact (see the paper cited below for details).
c@193: 
c@193: 
c@193: About this library
c@193: ------------------
c@193: 
c@126: This library provides:
c@126: 
c@126:  * Forward transform: time-domain to complex Constant-Q bins
c@126:  * Forward spectrogram: time-domain to interpolated Constant-Q
c@126:    magnitude spectrogram
c@126:  * Inverse transform: complex Constant-Q bins to time domain
c@126: 
c@163: The Vamp plugin provides:
c@163: 
c@163:  * Constant-Q magnitude spectrogram with high and low frequency
c@163:    extents defined in Hz
c@163:  * Constant-Q magnitude spectrogram with high and low frequency
c@163:    extents defined as MIDI pitch values
c@163:  * Pitch chromagram obtained by folding a Constant-Q spectrogram
c@163:    around into a single-octave range
c@163: 
c@193: 
c@193: Building the library and plugin
c@193: -------------------------------
c@193: 
c@193: To compile this code, use "make -f <file>" where <file> is one of
c@193: Makefile.linux, Makefile.osx, Makefile.mingw32 depending on
c@193: platform. These files set up some flags and include Makefile.inc,
c@193: which defines the input files and so forth. You could equally write
c@193: your own Makefile which does the same.
c@193: 
c@193: The Vamp plugin part of the build expects to find a compiled version
c@193: of the Vamp Plugin SDK in a neighbouring folder (../vamp-plugin-sdk).
c@193: The unit tests also require Boost headers to be available.
c@193: 
c@193: Note that this code uses the KissFFT library (compiled from source
c@193: bundled here) in its non-default double-precision mode via the use of
c@193: the flag -Dkiss_fft_scalar=double in Makefile.inc. If you want to
c@193: build this code using an external KissFFT library or custom build
c@193: scripts, you may need to do some work to ensure you have the right
c@193: configuration.
c@193: 
c@193: 
c@193: Credits
c@193: -------
c@193: 
c@126: The method is drawn from Christian Schörkhuber and Anssi Klapuri,
c@126: "Constant-Q transform toolbox for music processing", SMC 2010. See the
c@126: file CITATION for details. If you use this code in research work,
c@126: please cite this paper.
c@126: 
c@182: The C++ implementation is by Chris Cannam, Copyright 2014-2015 Queen
c@182: Mary, University of London.
c@126: 
c@126: The library is provided under a liberal BSD/MIT-style open source
c@126: licence. See the file COPYING for more information.
c@126: