view data/fileio/AudioFileReaderFactory.h @ 1196:c7b9c902642f spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef AUDIO_FILE_READER_FACTORY_H
#define AUDIO_FILE_READER_FACTORY_H

#include <QString>

#include "FileSource.h"
#include "base/BaseTypes.h"

class AudioFileReader;
class ProgressReporter;

class AudioFileReaderFactory
{
public:
    /**
     * Return the file extensions that we have audio file readers for,
     * in a format suitable for use with QFileDialog.  For example,
     * "*.wav *.aiff *.ogg".
     */
    static QString getKnownExtensions();

    /**
     * Return an audio file reader initialised to the file at the
     * given path, or NULL if no suitable reader for this path is
     * available or the file cannot be opened.
     *
     * If targetRate is non-zero, the file will be resampled to that
     * rate (transparently).  You can query reader->getNativeRate()
     * if you want to find out whether the file is being resampled
     * or not.
     *
     * If normalised is true, the file data will be normalised to
     * abs(max) == 1.0. Otherwise the file will not be normalised.
     *
     * If a ProgressReporter is provided, it will be updated with
     * progress status.  Caller retains ownership of the reporter
     * object.
     *
     * Caller owns the returned object and must delete it after use.
     */
    static AudioFileReader *createReader(FileSource source,
                                         sv_samplerate_t targetRate = 0,
                                         bool normalised = false,
                                         ProgressReporter *reporter = 0);

    /**
     * Return an audio file reader initialised to the file at the
     * given path, or NULL if no suitable reader for this path is
     * available or the file cannot be opened.  If the reader supports
     * threaded decoding, it will be used and the file decoded in a
     * background thread.
     *
     * If targetRate is non-zero, the file will be resampled to that
     * rate (transparently).  You can query reader->getNativeRate()
     * if you want to find out whether the file is being resampled
     * or not.
     *
     * If normalised is true, the file data will be normalised to
     * abs(max) == 1.0. Otherwise the file will not be normalised.
     *
     * If a ProgressReporter is provided, it will be updated with
     * progress status.  This will only be meaningful if threading
     * mode is not used because the file reader in use does not
     * support it; otherwise progress as reported will jump straight
     * to 100% before threading mode takes over.  Caller retains
     * ownership of the reporter object.
     *
     * Caller owns the returned object and must delete it after use.
     */
    static AudioFileReader *createThreadingReader(FileSource source,
                                                  sv_samplerate_t targetRate = 0,
                                                  bool normalised = false,
                                                  ProgressReporter *reporter = 0);

protected:
    static AudioFileReader *create(FileSource source,
                                   sv_samplerate_t targetRate,
                                   bool normalised,
                                   bool threading,
                                   ProgressReporter *reporter);
};

#endif