view transform/FeatureWriter.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.

    Sonic Annotator
    A utility for batch feature extraction from audio files.

    Mark Levy, Chris Sutton and Chris Cannam, Queen Mary, University of London.
    Copyright 2007-2008 QMUL.

    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 _FEATURE_WRITER_H_
#define _FEATURE_WRITER_H_

#include <string>
#include <map>
#include <vector>

#include <QString>

#include "Transform.h"

#include <vamp-hostsdk/Plugin.h>

using std::string;
using std::map;
using std::vector;

class FeatureWriter
{
public:
    virtual ~FeatureWriter() { }

    virtual string getDescription() const = 0;

    struct Parameter { // parameter of the writer, not the plugin
        Parameter() : hasArg(false), mandatory(false) { }
        string name;
        string description;
        bool hasArg;
        bool mandatory;
    };
    typedef vector<Parameter> ParameterList;
    virtual ParameterList getSupportedParameters() const {
        return ParameterList();
    }

    virtual void setParameters(map<string, string> &) {
        return;
    }

    struct TrackMetadata {
        QString title;
        QString maker;
        RealTime duration;
    };
    virtual void setTrackMetadata(QString /* trackid */, TrackMetadata) { }

    class FailedToOpenOutputStream : virtual public std::exception
    {
    public:
        FailedToOpenOutputStream(QString trackId, QString transformId) throw() :
            m_trackId(trackId),
            m_transformId(transformId)
        { }
        virtual ~FailedToOpenOutputStream() throw() { }
        virtual const char *what() const throw() {
            return QString("Failed to open output stream for track id \"%1\", transform id \"%2\"")
                .arg(m_trackId).arg(m_transformId).toLocal8Bit().data();
        }            
        
    protected:
        QString m_trackId;
        QString m_transformId;
    };

    /**
     * Notify the writer that we are about to start extraction for
     * input file N of M (where N is 1..M). May be useful when writing
     * multiple outputs into a single file where some syntactic
     * element is needed to connect them.
     */
    virtual void setNofM(int /* N */, int /* M */) { }

    // may throw FailedToOpenFile or other exceptions
    virtual void write(QString trackid,
                       const Transform &transform,
                       const Vamp::Plugin::OutputDescriptor &output,
                       const Vamp::Plugin::FeatureList &features,
                       std::string summaryType = "") = 0;

    /**
     * Throw FailedToOpenOutputStream if we can already tell that we
     * will be unable to write to the output file.  This is called to
     * test the output stream before processing begins.  The writer
     * may legitimately succeed here but still fail later -- this is
     * really an optimisation to ensure that easy-to-recognise failure
     * cases fail early.
     */
    virtual void testOutputFile(QString /* trackId */, TransformId) { }

    virtual void flush() { } // whatever the last stream was

    virtual void finish() = 0;

    virtual QString getWriterTag() const = 0;
};

#endif