QtFM::MidiPlayer Class

The MidiPlayer class plays a MidiFile on an Engine with FM instruments. More…

List of all members, including inherited members

Public Functions

Signals

Detailed Description

The player streams the notes into the engine a fraction of a second ahead of time, placing each on its own sample with Engine::playAt(), so the timing is exact whatever the event loop does. Instruments come from a PatchBank, by default PatchBank::generalMidi(): for a note of program n, the patch named program-n if the bank has one, else the patch of its General MIDI family; on channel 10, drum-k for key k, else the kit's drum for that key.

QString error;
const MidiFile song = MidiFile::fromData(data, &error);
if (!song.isValid()) {
    std::fprintf(stderr, "fmplay: %s\n", qPrintable(error));
    return 1;
}
EngineConfig config;
config.sampleRate = rate;
config.maxVoices = 64; // one voice per sounding note
if (chip == ChipType::OPL2 || chip == ChipType::OPL3)
    config.chips = {ChipType::OPL3}; // eighteen channels, like a Sound Blaster 16
Engine engine(config);
MidiPlayer player(&engine);
player.setInstruments(PatchBank::generalMidi(chip)); // the native bank for ChipType::None
player.setFile(song);

For an engine that is not started, call schedule() before each Engine::render().

Differences from Qt

Member Function Documentation

[explicit] QtFM::MidiPlayer::MidiPlayer(Engine *engine, QObject *parent = nullptr)

Constructs a player for engine, with parent.

[override] QtFM::MidiPlayer::~MidiPlayer()

Destroys the player, releasing its notes.

MidiFile QtFM::MidiPlayer::file() const

Returns the music.

[signal] void QtFM::MidiPlayer::finished()

This signal is emitted when music that does not loop has ended.

float QtFM::MidiPlayer::gain() const

Returns the gain of the music in decibels.

Patch QtFM::MidiPlayer::instrument(int channel, int program, int key) const

Returns the patch that plays key key of program program on channel.

PatchBank QtFM::MidiPlayer::instruments() const

Returns the instruments.

bool QtFM::MidiPlayer::isPlaying() const

Returns true while the music plays.

bool QtFM::MidiPlayer::loops() const

Returns true if the music loops.

void QtFM::MidiPlayer::play()

Plays the music from its start.

double QtFM::MidiPlayer::position() const

Returns the position in the music in seconds; for looping music, within the current pass.

void QtFM::MidiPlayer::schedule(quint64 untilFrame)

Starts the notes that begin before the engine's frame untilFrame. A started engine is fed by a timer; for an engine that is pulled with Engine::render(), call it before each render with the frame the render will reach. Emits finished() once the music has ended.

void QtFM::MidiPlayer::setFile(const MidiFile &file)

Sets the music to file, stopping what plays.

void QtFM::MidiPlayer::setGain(float dB)

Sets the gain of the music to dB, for the notes not yet started.

void QtFM::MidiPlayer::setInstruments(const PatchBank &bank)

Sets the instruments to the patches of bank.

void QtFM::MidiPlayer::setLoops(bool loops)

Sets whether the music starts again when it ends to loops.

void QtFM::MidiPlayer::setTranspose(int semitones)

Sets the transposition of every note but the drums to semitones.

void QtFM::MidiPlayer::stop()

Stops the music, releasing its notes.

int QtFM::MidiPlayer::transpose() const

Returns the transposition in semitones.