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Tracks are the fundamental building blocks of your project in Lumix. Each track can contain multiple clips and has its own audio processing chain, controls, and properties.

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Track Types

Lumix supports three types of tracks:

Audio Tracks

For recording and playing back audio files like WAV, MP3, and other audio formats

MIDI Tracks

For MIDI data, virtual instruments, and sequencing

Group Tracks

For organizing and processing multiple tracks together

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Track Type Enum

Lumix/Tracks/Track.cs
public enum TrackType
{
    Audio,
    Midi,
    Group
}

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Core Properties

Every track in Lumix has the following core properties:

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Identity & Naming

Lumix/Tracks/Track.cs
public string Id { get; set; } = Guid.NewGuid().ToString();
public string Name { get; protected set; }
Each track has a unique identifier and a user-customizable name.

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Audio Properties

Lumix/Tracks/Track.cs
public float Volume { get; private set; }
public float Pan { get; private set; }
public bool Enabled { get; private set; } = true;
public bool Solo { get; private set; }
public bool RecordOnStart { get; private set; }
Volume ranges from -90dB to +6dB and is converted to linear gain using the formula: Math.Pow(10, volume / 20)

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Visual Properties

Lumix/Tracks/Track.cs
public Vector4 Color { get; protected set; }
Each track has a customizable color that can be applied to all its clips.

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Clips Collection

Lumix/Tracks/Track.cs
/// <summary>
/// The clips of this track
/// </summary>
public List<Clip> Clips = new();
Tracks contain a collection of clips that are arranged on the timeline.

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Audio Engine

Each track has its own audio processing engine:
Lumix/Tracks/Track.cs
public TrackEngine Engine { get; protected set; }
The engine handles:
  • Audio/MIDI playback
  • Plugin processing chain
  • Recording
  • Volume metering
  • Stereo panning

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Time Selection

Tracks support time-based selection for editing operations:
Lumix/Tracks/Track.cs
/// <summary>
/// Selected time of the track in musical time
/// </summary>
public TimeSelection TimeSelectionArea { get; protected set; } = new();
1

Start Selection

Click on the track to begin a time selection
2

Drag to Extend

Drag to extend the selection area across the timeline
3

Create Clip

Use Ctrl+Shift+M (MIDI tracks) to create a clip from the selected area

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Track Controls

Tracks provide several control methods:

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Volume Control

Volume is controlled via a drag slider that ranges from -90dB to +6dB:
Lumix/Tracks/Track.cs
if (UiElement.DragSlider($"{FontAwesome6.VolumeHigh}##track_volume", 105, ref _volume, 0.1f, -90f, 6f, "%.1f", ImGuiSliderFlags.AlwaysClamp | ImGuiSliderFlags.NoInput))
{
    float linearVolume = (float)Math.Pow(10, _volume / 20);
    Engine.StereoSampleProvider.SetGain(linearVolume);
}
Double-click the volume slider to reset to 0dB (unity gain).

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Panning Control

Pan ranges from -50 (full left) to +50 (full right):
Lumix/Tracks/Track.cs
if (UiElement.DragSlider($"{FontAwesome6.RightLeft}##track_pan", 105, ref _pan, 0.1f, -50f, 50f, "%.0f", ImGuiSliderFlags.AlwaysClamp | ImGuiSliderFlags.NoInput))
{
    float mappedPan = _pan / 50f;
    Engine.StereoSampleProvider.Pan = mappedPan;
}
Double-click the pan slider to reset to center (0).

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Solo Behavior

Lumix/Tracks/Track.cs
if (UiElement.Toggle($"{Fontaudio.Solo}##track_solo", _solo, new Vector4(0.17f, 0.49f, 0.85f, 1f), new(35, 25)))
{
    _solo = !_solo;
    ArrangementView.Tracks.ToList().ForEach(track =>
    {
        if (track == this)
        {
            if (ImGui.IsKeyDown(ImGuiKey.ModCtrl))
                _enabled = !_enabled;
            else
                _enabled = true;
        }
        if (track != this)
        {
            if (!ImGui.IsKeyDown(ImGuiKey.ModCtrl))
            {
                track._enabled = !_solo;
                track._solo = false;
            }
        }
    });
}
Holding Ctrl while clicking solo allows multiple tracks to be soloed simultaneously.

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Audio-Specific Tracks

Audio tracks handle audio file playback:
Lumix/Tracks/AudioTracks/AudioTrack.cs
public class AudioTrack : Track
{
    public override TrackType TrackType => TrackType.Audio;

    public AudioTrack(string name)
    {
        Name = name;
        Vector4 trackCol = ImGuiTheme.GetRandomColor();
        Color = trackCol;
        Engine = new TrackAudioEngine(this, AudioSettings.SampleRate);
        Engine.VolumeMeasured += (sender, e) =>
        {
            _leftChannelGain = e.MaxSampleValues[0];
            _rightChannelGain = e.MaxSampleValues[1];
        };
        ArrangementView.MasterTrack.AudioEngine.AddTrack(Engine);
    }
}

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MIDI-Specific Tracks

MIDI tracks handle MIDI data and virtual instruments:
Lumix/Tracks/MidiTracks/MidiTrack.cs
public class MidiTrack : Track
{
    public override TrackType TrackType => TrackType.Midi;

    public MidiTrack(string name = "")
    {
        Name = name;
        Vector4 trackCol = ImGuiTheme.GetRandomColor();
        Color = trackCol;
        Engine = new TrackMidiEngine(this, AudioSettings.SampleRate);
        Engine.VolumeMeasured += (sender, e) =>
        {
            _leftChannelGain = e.MaxSampleValues[0];
            _rightChannelGain = e.MaxSampleValues[1];
        };
        ArrangementView.MasterTrack.AudioEngine.AddTrack(Engine);
    }
}

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Creating MIDI Clips

MIDI tracks can create clips programmatically:
Lumix/Tracks/MidiTracks/MidiTrack.cs
public void CreateMidiClip(long time)
{
    var clip = new MidiClip(this, time);
    Clips.Add(clip);
}

public void CreateMidiClip(TimeSelection time)
{
    var clip = new MidiClip(this, time);
    Clips.Add(clip);
}
Double-clicking on an empty area of a MIDI track automatically creates a new clip at that position.

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Track Operations

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Duplicating Tracks

Tracks can be duplicated with all their settings and clips:
Lumix/Tracks/Track.cs
if (ImGui.MenuItem("Duplicate", "Ctrl+D"))
{
    if (this is AudioTrack)
    {
        // Create new track and copy data
        var track = ArrangementView.NewAudioTrack(this.Name, ArrangementView.Tracks.IndexOf(this) + 1);
        foreach (AudioClip clip in Clips.Cast<AudioClip>())
        {
            var copy_clip = new AudioClip(track, clip.Clip, clip.StartTick) { 
                Enabled = clip.Enabled,
                Color = clip.Color
            };
            track.Clips.Add(copy_clip);
        }
        track._enabled = this.Enabled;
        track._volume = this.Volume;
        // ... additional properties copied
    }
}

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Reordering Tracks

Tracks can be moved up or down in the arrangement:
Lumix/Tracks/Track.cs
if (UiElement.Button($"{FontAwesome6.ArrowUp}", new(22, 25)))
{
    var copy = this;
    int idx = ArrangementView.Tracks.IndexOf(this);
    if (idx > 0)
    {
        var target = ArrangementView.Tracks[idx - 1];
        ArrangementView.Tracks[idx] = target;
        ArrangementView.Tracks[idx - 1] = copy;
    }
}

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Volume Metering

Each track displays real-time audio level metering:
Lumix/Tracks/Track.cs
// Smooth gain variables (adjusted for smoother transitions)
_smoothLeftChannelGain = Lerp(_smoothLeftChannelGain, _leftChannelGain, smoothingFactor);
_smoothRightChannelGain = Lerp(_smoothRightChannelGain, _rightChannelGain, smoothingFactor);
The meters show stereo levels with smoothing applied for visual stability.

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Keyboard Shortcuts

ShortcutAction
Ctrl+TInsert Audio Track
Ctrl+Shift+TInsert MIDI Track
Ctrl+DDuplicate Track
Ctrl+RRename Track
DelDelete Track
Ctrl+Shift+MCreate MIDI Clip from Selection

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See Also

Clips

Learn about clip management and editing

Timeline

Understand the timeline and arrangement system

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