About PassThru

PassThru lets you view and monitor live video from cameras, capture cards, windows, and screens on your desktop. Built as a capture card companion, it works with any video or audio source your system recognizes and can record footage or save instant replay clips.

Getting Started

When you first open PassThru, you'll see a placeholder screen with two buttons:

• Open Settings — configure your video and audio sources
• Restore Session — resume your previous source configuration (appears after your first session)

Selecting Sources

Open Settings and go to the Sources tab. You'll see two sections:

Video Source

Choose a source type using the buttons at the top:

Type	Description
Camera	USB cameras, webcams, and capture cards (e.g. Elgato, AVerMedia). Select from the dropdown — the resolution and frame rate options update automatically based on what the device supports. The highest supported option is labeled (Source Max).
Window	Capture a specific application window. Thumbnails are shown for each available window. Full window only (no crop).
Screen	Capture an entire monitor or display. Use the Select Region tile to enter viewfinder mode and frame a specific area.
Select Region	Enters viewfinder mode for screen capture. Reposition and resize the PassThru window to frame the area you want to capture, then click Done in the title bar. If no stream is active, it starts automatically. The dotted border shows the capture area and remains visible while recording.

PassThru does not appear in its own window list. If the captured window is closed, PassThru clears the source so you can open Settings and pick it again after reopening the window.

Audio Source

Select a Primary Audio device from the first dropdown. Optionally select a Secondary Audio device to mix a second source alongside the primary — useful for capturing a microphone and system audio simultaneously.

Use the Test button next to each dropdown to open an inline level meter for that device. Click Stop to close it. Both sources can be tested independently before applying settings.

Each source has an Apply Processing toggle that controls whether the audio processing settings from Tweaks (echo cancellation, noise suppression, auto gain) are applied to that source. Primary defaults to on; Secondary defaults to off. Turn processing off for capture cards, phones, or any source where you want the audio passed through unmodified.

Click Apply Changes to start streaming.

Controls Bar

The controls bar at the bottom of the window provides quick access to common actions:

Control	Description
Play / Pause	Pause and resume the video and audio stream.
Record	Start and stop recording the stream to a file. A timer shows the recording duration, and briefly shows "Saved" or "Save failed" when the file is written. The button pulses red while recording.
Save Clip	Save the contents of the replay buffer as a clip file (only active when the replay buffer is enabled).
Volume	Click the speaker icon to mute or unmute. Use the slider to adjust volume.
Settings	Open the settings overlay.
Fullscreen	Toggle fullscreen mode.

Title Bar

The title bar shows the app name and window controls (minimize, maximize, close). The title bar and controls bar auto-hide after 5 seconds of inactivity and reappear when you move the mouse. The window can be dragged from the title bar area.

Stats Overlay

PassThru includes a real-time performance overlay that can be toggled on and off with a keyboard shortcut (configurable in Settings > Shortcuts). The overlay displays:

Stat	Description
RES	The resolution of the incoming video stream.
FPS	Frames per second being delivered by the source. This is not your game's FPS — it's the rate at which unique frames arrive from the capture device. If your capture card outputs at 60fps, this should read close to 60 regardless of what the game is rendering.
LAT	Estimated video latency in milliseconds, measured from the moment the capture device grabs the frame to when it's displayed on screen. Shows "N/A" for screen and window captures, which don't provide capture timestamps.
DROP	Dropped frames per second. Compares frames received against what's expected based on your configured frame rate. A non-zero value means some frames aren't making it through — try lowering resolution or frame rate.
AUDIO	The audio sample rate and channel mode (e.g. 48kHz Stereo).

Settings

Settings are organized into four tabs:

Sources

Video and audio source selection, as described above.

Tweaks

Capture Quality

• Resolution — dynamically populated based on the selected camera's capabilities. Falls back to standard options (1080p, 720p, 480p, 360p) if detection isn't available. The highest supported option is labeled (Source Max).
• Frame Rate — also dynamically detected. Standard options range from 15 FPS to 144 FPS depending on device support. Defaults to 60 FPS. The highest supported rate is labeled (Source Max).

Display

Setting	Description
Scale Mode	Contain (letterbox), Cover (crop to fill), Stretch (ignore ratio), or Natural (pixel-perfect 1:1).
Aspect Ratio	Override the display ratio: Auto, 16:9, 4:3, 21:9, 32:9, or 1:1.
Mirror	Flip the video horizontally.
Rotation	Rotate the display by 0°, 90°, 180°, or 270°.
Stats Overlay Position	Choose which corner the stats overlay appears in: Top Left, Top Right, Bottom Left, or Bottom Right.

Audio Processing

These settings apply to any audio source that has Apply Processing enabled in Sources.

Setting	Description
Channel Mode	Toggle between mono and stereo. Stereo is the default. Enabling stereo disables the processing options below.
Processing	Echo cancellation, noise suppression, and auto gain control. Disabled when stereo is active. Intended for microphone sources.
Latency	Low (Interactive) for minimum delay, Balanced for general use, or High (Playback) for stability on slower hardware.

Shortcuts

Assign custom keyboard shortcuts for common actions. Click an input field, then press a key combination (e.g. Ctrl+R) to assign it. Press Esc or Backspace to clear a shortcut.

Action	Description
Save Clip	Save the replay buffer as a clip file.
Toggle Recording	Start or stop recording.
Toggle Fullscreen	Enter or exit fullscreen mode.
Toggle Mute	Mute or unmute audio.
Toggle Stats	Show or hide the performance stats overlay.

Advanced

Recording

• Format — choose from supported recording formats (WebM VP9/VP8, MP4 H.264). Only formats your system supports are listed.
• Video quality — High (larger files), Medium, or Low (smaller files). Applies to both recordings and saved clips.
• Save Folder — set a default folder for recordings. If not set, you'll be prompted each time. Files are named with a timestamp, e.g. recording-2026-02-20T14-30-00.webm.

Replay Buffer

The replay buffer continuously records in the background so you can save the last few minutes of footage on demand — even when you're not actively recording. Similar to Nvidia ShadowPlay's Instant Replay.

• Enable — toggle the replay buffer on or off. When enabled, it starts automatically with the stream.
• Buffer Duration — how much footage to keep: 1, 2, 5 (default), or 10 minutes. Longer buffers use more memory.
• Clip Save Folder — set a default folder for clips. Clip files are named like clip-2026-02-20T14-30-00.webm.

Profiles

PassThru supports multiple named settings profiles so you can keep separate configurations for different use cases — for example a camera setup, a screen capture preset, and a podcast layout — and switch between them instantly without opening Settings.

Feature	Description
Title bar switcher	Click the profile name next to the PassThru logo to open a quick-switcher. The active profile is highlighted; the default is marked with a star. Selecting a different profile applies it immediately and restarts the stream.
Manage Profiles	Accessible from the bottom of the switcher popover. Rename, delete, set as default, or create new profiles. New profiles can be seeded from your current settings or from factory defaults.
Settings File	All profiles are stored together in a single settings.json file in the app data folder. The file path is shown in Advanced > Profiles. You can back it up, inspect it, or copy the path to locate it in your file manager.
Export Profile	Save the active profile to a JSON file for backup or transfer to another machine.
Import Profile	Load a previously exported JSON file into the active profile, overwriting its current settings.

Tips for Low Latency

• Set audio latency to Low (Interactive) in Tweaks > Audio.
• Use Stereo mode to bypass audio processing (echo cancellation, noise suppression, auto gain).
• Higher resolutions and frame rates look better but require more processing. If you experience lag, try lowering the resolution or frame rate.
• The biggest latency factor is usually the capture device itself. Software can only optimize what happens after the frame arrives.

Session Persistence

All settings are saved automatically to a JSON file in the app data folder whenever you apply changes. Each named profile is stored independently within that file. When you relaunch PassThru, your previous configuration is available via the Restore Session button. You can also export and import any profile as a JSON file to back up or transfer configurations between machines.