Backtracking User Guide

Choose what to capture

On Windows, route the source to the default playback device. If a DAW uses ASIO, exclusive mode, or another direct output path, use the plug-in to sample its track signal. On macOS, grant system audio recording permission when the desktop app first prompts you. Windows WASAPI · Apple Core Audio

Open settings

Click the gear in the toolbar or right-click inside the Backtracking window to open Options. The desktop app opens a separate window. VST3 and CLAP open Options inside the DAW's plug-in editor. The controls are grouped by category, including capture, theme accent, history length, auto-resume, transparency, WAV format, and folders. On desktop, you can also toggle Keep on top from the toolbar.

Choose a category on the left, then use the vertical settings list on the right. Larger bold titles, group headings, and body/control text of at least 15 distinguish hierarchy. History, auto-resume, transparency, and WAV format use dropdowns sized to their item count, up to ten rows before scrolling. Scroll the details pane for longer content. Desktop Options can be resized and keeps Close visible. The plug-in requests a larger editor and restores its prior size when closed.

Operating instructions live in this guide; the UI keeps controls, headings, labels, values, and necessary status/error/path information.

Keep quiet sections

Enable Keep quiet sections under Options → Capture (macOS label: 保留安靜片段). It defaults to Off, including older settings/projects without this field.

• Off: existing silence compression omits long below-threshold gaps from the retained duration.
• On: retain subsequent quiet input, digital zeros, and silence established by a known source clock. Quiet sections consume History and can displace older audio sooner.
• Toggling changes future capture only. It preserves retained history, fixed editing material/aligned A/B ranges, and capture state. It neither retroactively compresses existing material nor restores discarded quiet audio.
• Manual Pause, unavailable sources, and disconnected Senders retain their own behavior. Enabling the option does not invent unknown audio or DAW timing without a valid source/clock.

Windows handles eligible no-packet silence with periodic padding. With no callback on macOS, a real subsequent timestamp is needed to establish the interval; immediate trailing padding is not promised. Platform validation is tracked in the current plan, separately from older benchmarks. Desktop preferences and individual plug-in instances store the option.

In the macOS desktop app, use a mouse right-click or the trackpad's secondary click to open the menu. Use Control with a click and drag over the waveform to select audio.

The settings menu offers five background transparency levels. Choose 0%, 25%, 50%, 75%, or 100%, where 0% is opaque and 100% is clear. On the desktop apps, you can open Settings and adjust the value even at 100%. In VST3 and CLAP, Panel transparency fades the waveform panel's fill. The DAW provides the background behind it.

Sources, waveforms, and flags

• Choose system playback, a microphone, or a specific app in desktop Options. App capture requires Windows OS build 20348 or later. On macOS, grant the relevant system audio or microphone permission when prompted.
• The source list updates each time you open the drop-down. Windows lists apps with an open playback stream, including paused streams. macOS lists apps that Core Audio identifies as playback sources. If an app is missing, play some audio in it and reopen the list. Microphone entries come from the input devices the system currently makes available.
• Enable A and B to capture two routes. For each, choose a source and Left, Right, Center, Mid, Side, or Merged. Merged uses the source's mono or stereo output format. Center requires a native center channel.
• On Windows, A/B routes from the same source, such as System Side and System Mid, use the device's native sample rate. Export converts the whole selection if the WAV rate differs. Capture also smooths the splice when you resume after a pause.
• For one source, choose a merged waveform or two L/R rows. With A/B enabled, A and B each use half the waveform area and have independent meters.
• Flags mark range boundaries. Shift-drag directly creates a snapped selection; Ctrl on Windows / Option on macOS keeps free selection, with optional Shift for snapping. Targets prioritize visible flags, then painted bars, then painted seconds; the moving handle excludes itself. Only painted targets are eligible. Fully transparent backgrounds hide guides but retain interactive flags.
• Selecting, adjusting flags, zooming, or panning fixes the original editing material/view while background capture continues. The selected samples and aligned A/B boundaries survive live rollover or a shorter history limit. Finishing/canceling returns to live view without changing manual Pause.
• Waveform bins, strokes, and guide density adapt to the actual audio rectangle, visible duration, and interaction state.
• Wider views use a continuous filled min/max envelope and outline; close views connect the original samples with a polyline. The width-based zoom limit allows about four logical pixels per sample. Resizing preserves the view; subsequent zooming follows valid limits. Drawing does not change selected or exported samples; see the current-round record for validation status.
• Save snapshot, the global snapshot shortcut, and accepted drops export both tracks with the same boundaries and sample rate. If your DAW prompts for placement, choose separate tracks at the same start position.

Desktop update settings

Show waveform only

Turn on Show waveform only to shrink the native Windows/macOS desktop window to the waveform panel plus its visible border and disable the native shadow. Background transparency still follows Options: opaque, translucent, or fully transparent. Waveforms and flags remain visible and interactive at 100% transparency. Plug-ins can request a smaller editor; the DAW manages its outer frame, shadow, and background. This setting defaults to Off and is saved with the desktop preferences or the plug-in's DAW project settings.

Right-click the waveform to open Options. Choose Play (開始錄音 in the macOS app) when capture is paused, or Pause (暫停錄音) when capture is armed or recording.

When you switch modes, the desktop window fits the waveform panel's existing height and removes excess transparent space above and below it. Drag either inside side edge to adjust the width or the top and bottom edges to adjust the height. A narrower window shows the same retained duration over a shorter distance, reducing the number of pixels the waveform scrolls per second. The waveform shrinks to fit a shorter window. Turning the mode off restores the previous full-interface window size.

To restore the full interface, right-click the waveform and turn off Show waveform only. Windows/macOS native shadows are disabled in this mode; the optional thin border is controlled separately in Appearance Options.

Move and resize the desktop window

The Windows and macOS desktop apps use a frameless window. The gestures below move and resize it without automatic snapping near screen edges. The DAW manages the outer window for VST3 and CLAP. To close the desktop app, choose Quit from Settings.

With Keep on top enabled on Windows, Backtracking reasserts its position when the taskbar or another window on the same desktop covers it, while leaving input focus where it is. Windows manages the secure desktop and protected system surfaces.

Use the Windows system tray icon to show or hide the window. Capture can continue while the window is hidden. Choose Quit from the tray or Settings to exit. Place Backtracking.exe in a permanent location and enable Start with Windows to open Backtracking at its last window position when you sign in.

On macOS, use the menu bar item to show, hide, or quit Backtracking, or enable launch at login. If macOS asks for approval, allow the Backtracking login item in System Settings.

Read the waveform and capture status

In the full interface, the toolbar's Play/Pause icon shows the available action: Start capture or Pause capture.

• Waiting for sound. Armed capture waits for the silence threshold when Keep quiet sections is Off. With it On, known silence from a valid source can be retained; unavailable sources are handled separately.
• Recording. The red indicator blinks. The newest audio appears on the right. Once the buffer fills, new audio gradually replaces the oldest samples.
• Paused. Pause stops background capture and skips incoming audio. Play and existing auto-resume control capture separately; manual Pause remains at the zero-second setting. Selection, flags, zoom, and export preparation fix the editing view without implicitly pausing or forcing capture to resume.
• Capture unavailable. If the desktop recorder loses its connection, press Play to retry.

History / Buffer offers 10/20/30/60 seconds or 3/5/10 minutes and defaults to 20 seconds. With default silence compression, two five-second sounds a minute apart join with only a short gap; Keep quiet sections also counts known silence against History. Very quiet input may fall below the default gate. Shortening trims the oldest live audio; lengthening gives future audio more room. Fixed editing material is not recut.

Live audio meter

The meter next to the gear reads the incoming audio signal and defaults to dBFS. Choose the unit in the gear menu. In the macOS desktop app, you can also click the readout to switch units. The meter displays — while paused or when a reading is unavailable.

Loudness measurement references. ITU-R BS.1770 · EBU Tech 3341

Select and drag out

In the full interface, hover over an unselected waveform to preview all retained audio. Drag from anywhere on the waveform outside Backtracking onto a WAV target to export that range. For example, a full 20-second buffer exports 20 seconds; if only 7 seconds have been captured, the WAV is 7 seconds long. Both display modes invert the waveform-line color inside free or Shift-snapped selections. The selected range is used for export.

Clicking, selecting, and dragging within the window only affect the waveform. To export a selected clip, drag it out and drop it on a target that accepts WAV files, or choose Save snapshot in Options. Canceled or rejected drops, including drops back in the source window, leave no export file. Keep the mouse button held while an export finishes preparing. If the DAW rejects the drop, choose Save snapshot in Options and import the WAV from the saved snapshots folder.

With Backtracking focused, press Esc or Backspace to cancel editing and return to live view without writing a file. Background capture keeps its prior state; a manual Pause is not cleared.

Save a snapshot

Choose Save snapshot in Options to save from the current recorder. A selection uses its original fixed samples with the same A/B sample boundaries. With no selection, it saves all audio retained when triggered. Saving neither implicitly pauses capture nor forces manual Pause to resume. Selected-range completion can return to live view; completion of a background full-history save does not cancel a selection created afterward.

On Windows, press Alt plus the physical key to the left of 1 (the ~ / grave key, without Shift). On macOS, press Fn/Globe plus that same physical key. The global shortcut works from the background, without focusing Backtracking or the plug-in editor. On Linux, use the snapshot shortcut helper. Options can select one plug-in instance as the global shortcut target. Backtracking does not bind Ctrl+S; it remains available to save the DAW project.

Arm, pause, and auto-resume capture

Choose Play to arm capture or Pause to pause it manually. Use the toolbar in the full interface or right-click to open Options in waveform-only mode. Play preserves fixed editing material/selection; canceling, an ordinary click, or export completion returns to live view. Once re-armed, the next sound appends to live history within the limit.

Auto-resume retains 0/5/10 seconds and its 10-second default. Editing fixes material/view without implicitly pausing capture. Canceling, an ordinary waveform click, or export completion returns live without forcing manual Pause to resume. Play and existing auto-resume control capture separately: manual Pause remains at zero seconds; 5/10 seconds retain their timer rules. Keep quiet sections determines whether quiet/zero input is retained while armed.

Existing Off, 20-second, and 30-second settings use the 10-second default.

Clear the current recording

Click the trash icon in the toolbar. It is labeled Clear capture on Windows desktop and Clear captured audio in the plug-ins. This empties the waveform, selection, and audio held in memory. If capture is armed, incoming sound starts filling the waveform again. You can find previously exported WAVs in the save folder.

Output location and file format

You can choose and open both folders from Options. Successful drops use the default export folder. The global snapshot shortcut and Save snapshot use the saved snapshots folder. Existing export destinations are carried forward.

Choose the sample rate and encoding independently in the gear menu.

Snapshot saves and drag-and-drop exports use the current WAV settings. Any sample rate conversion happens during export. On desktop, Left and Right export as stereo with audio on the corresponding side, Side exports as stereo with an inverted right channel, and Mid and Center export as mono. Merged and the plug-ins use the captured channel count.

Enable Export every file as mono to export each WAV in mono. Stereo Merged and stereo plug-in captures average the left and right channels. Side exports the captured Side signal. A and B still export as individual files. The option defaults to Off. The rolling history lives in memory, so export any clips you need before closing the app or removing the plug-in.

Save and restore settings

The Windows and macOS desktop apps save your history length, auto-resume delay, theme accent, background transparency, meter mode, WAV export settings, both folders, keep-on-top setting, and waveform-only mode as you change them. Those preferences are restored the next time you open the app.

• Windows. Settings are stored in %LOCALAPPDATA%\Backtracking\Settings, with %APPDATA%\Backtracking\Settings as a fallback when LOCALAPPDATA is unavailable. The app restores its previous window position.
• macOS. Settings are stored in the macOS user preferences. The app also restores the desktop window's size and position.

For VST3 and CLAP, the DAW project stores each plug-in instance's history length, auto-resume delay, theme accent, panel transparency, meter mode, WAV export settings, both folders, and waveform-only mode. Save the project manually after making changes. When you reopen that project, the DAW restores each instance's settings.

Troubleshooting

Offline rendering. CLAP skips capture when the host reports offline mode. The nice-plug 0.4.2 VST3 wrapper can pass the previous processing mode to Backtracking, so an offline render may enter the capture history. Export important clips before rendering. To stop capture for the entire render, set auto-resume to 0 seconds, then press Pause, avoiding the 5/10-second timer. A fixed editing view alone does not stop recording.