view data/fileio/MP3FileReader.h @ 1881:b504df98c3be

Ensure completion on output model is started at zero, so if it's checked before the input model has become ready and the transform has begun, it is not accidentally reported as complete (affected re-aligning models in Sonic Lineup when replacing the session)

/* -*- 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 SV_MP3_FILE_READER_H
#define SV_MP3_FILE_READER_H

#ifdef HAVE_MAD

#include "CodedAudioFileReader.h"

#include "base/Thread.h"
#include <mad.h>

#include <set>
#include <atomic>

class ProgressReporter;

class MP3FileReader : public CodedAudioFileReader
{
    Q_OBJECT

public:
    /**
     * How the MP3FileReader should handle leading and trailing gaps.
     * See http://lame.sourceforge.net/tech-FAQ.txt for a technical
     * explanation of the numbers here.
     */
    enum class GaplessMode {
        /**
         * Trim unwanted samples from the start and end of the decoded
         * audio. From the start, trim a number of samples equal to
         * the decoder delay (a fixed 529 samples) plus any encoder
         * delay that may be specified in Xing/LAME metadata. From the
         * end, trim any padding specified in Xing/LAME metadata, less
         * the fixed decoder delay. This usually results in "gapless"
         * audio, i.e. with no spurious zero padding at either end.
         */
        Gapless,

        /**
         * Do not trim any samples. Also do not suppress any frames
         * from being passed to the mp3 decoder, even Xing/LAME
         * metadata frames. This will result in the audio being padded
         * with zeros at either end: at the start, typically
         * 529+576+1152 = 2257 samples for LAME-encoded mp3s; at the
         * end an unknown number depending on the fill ratio of the
         * final coded frame, but typically less than 1152-529 = 623.
         *
         * This mode produces the same output as produced by older
         * versions of this code before the gapless option was added,
         * and is present mostly for backward compatibility.
         */
        Gappy
    };
    
    MP3FileReader(FileSource source,
                  DecodeMode decodeMode,
                  CacheMode cacheMode,
                  GaplessMode gaplessMode,
                  sv_samplerate_t targetRate = 0,
                  bool normalised = false,
                  ProgressReporter *reporter = 0);
    virtual ~MP3FileReader();

    QString getError() const override { return m_error; }

    QString getLocation() const override { return m_source.getLocation(); }
    QString getTitle() const override { return m_title; }
    QString getMaker() const override { return m_maker; }
    TagMap getTags() const override { return m_tags; }
    
    static void getSupportedExtensions(std::set<QString> &extensions);
    static bool supportsExtension(QString ext);
    static bool supportsContentType(QString type);
    static bool supports(FileSource &source);

    int getDecodeCompletion() const override { return m_completion; }

    bool isUpdating() const override {
        return m_decodeThread && m_decodeThread->isRunning();
    }

public slots:
    void cancelled();

protected:
    FileSource m_source;
    QString m_path;
    QString m_error;
    QString m_title;
    QString m_maker;
    TagMap m_tags;
    GaplessMode m_gaplessMode;
    sv_frame_t m_fileSize;
    double m_bitrateNum;
    int m_bitrateDenom;
    int m_mp3FrameCount;
    int m_completion;
    bool m_done;

    unsigned char *m_fileBuffer;
    size_t m_fileBufferSize;
    
    float **m_sampleBuffer;
    size_t m_sampleBufferSize;

    ProgressReporter *m_reporter;
    std::atomic<bool> m_cancelled;

    bool m_decodeErrorShown;

    struct DecoderData {
        unsigned char const *start;
        sv_frame_t length;
        bool finished;
        MP3FileReader *reader;
    };

    bool decode(void *mm, sv_frame_t sz);
    enum mad_flow filter(struct mad_stream const *, struct mad_frame *);
    enum mad_flow accept(struct mad_header const *, struct mad_pcm *);

    static enum mad_flow input_callback(void *, struct mad_stream *);
    static enum mad_flow output_callback(void *, struct mad_header const *,
                                         struct mad_pcm *);
    static enum mad_flow filter_callback(void *, struct mad_stream const *,
                                         struct mad_frame *);
    static enum mad_flow error_callback(void *, struct mad_stream *,
                                        struct mad_frame *);

    class DecodeThread : public Thread
    {
    public:
        DecodeThread(MP3FileReader *reader) : m_reader(reader) { }
        void run() override;

    protected:
        MP3FileReader *m_reader;
    };

    DecodeThread *m_decodeThread;

    void loadTags(int fd);
    QString loadTag(void *vtag, const char *name);
};

#endif

#endif