Capture a webcam in Unity with VideoCaptureCoreX¶

Video Capture SDK .Net Media Blocks SDK .Net

The VideoCaptureX scene captures from a local webcam (and microphone) with the high-level VideoCaptureCoreX engine, previews the live frames into a Unity RawImage, and records to an MP4 file at the same time. You can also capture a webcam with the low-level MediaBlocksPipeline API — that recipe is in Capture with the Media Blocks pipeline below. This article assumes you have imported the Unity package and applied the required project settings; see Using VisioForge in Unity first.

The OnVideoFrameUnity event¶

VideoCaptureCoreX exposes the Unity-only OnVideoFrameUnity event: each frame arrives as tightly packed RGBA32 (Stride == Width * 4), ready for Texture2D.LoadRawTextureData with no conversion. Subscribe before StartAsync.

Run the sample¶

1. Connect a webcam, then open Assets/Scenes/SampleScene.unity.
2. In the Hierarchy select the RawImage GameObject — the VideoCaptureXRecorder component is attached to it.
3. In the Inspector set Camera Index and the Output Path.
4. Press ▶ Play — the live camera renders into the Game view. Toggle recording with StartRecordingAsync() / StopRecordingAsync() (for example from a UI button).

Inspector fields¶

The pipeline¶

graph LR;
    cap["VideoCaptureCoreX (headless)"] -->|OnVideoFrameUnity, RGBA32| view["VisioForgeVideoView (Texture2D)"];
    cap -->|record| mp4["MP4Output (H264 + AAC)"];

The core of the preview + record setup:

var cameras = await DeviceEnumerator.Shared.VideoSourcesAsync();

_capture = new VideoCaptureCoreX();
_capture.Video_Source = new VideoCaptureDeviceSourceSettings(cameras[cameraIndex]);

var audioSources = await DeviceEnumerator.Shared.AudioSourcesAsync();
if (audioSources.Length > 0)
    _capture.Audio_Source = audioSources[0].CreateSourceSettingsVC();

// Texture-ready RGBA32 frames straight into the view.
_capture.OnVideoFrameUnity += _videoView.OnFrameBuffer;

// Pre-register the MP4 output (autostart:false) so preview runs without recording.
_capture.Outputs_Add(new MP4Output(outputPath), autostart: false);

await _capture.StartAsync();

Recording is toggled at runtime so the preview keeps running independently of capture-to-file:

await _capture.StartCaptureAsync(0, outputPath); // begin recording
await _capture.StopCaptureAsync(0);              // stop recording

Capture with the Media Blocks pipeline (low-level)¶

VideoCaptureCoreX is the high-level engine. For full control over the pipeline you can capture the same webcam with the low-level MediaBlocksPipeline API — the approach the SimplePlayer / RTSPViewer scenes use. There is no prebuilt webcam scene for this path; add the recipe below to your own MonoBehaviour (model it on the bundled MediaBlocksPlayer):

A TeeBlock splits the camera video so it feeds the preview (BufferSinkBlock) and the recording (MP4OutputBlock, which bundles the H.264 + AAC encoders and the MP4 muxer) at the same time. The microphone is added straight to the MP4 output:

graph LR;
    cam[SystemVideoSourceBlock] --> tee[TeeBlock];
    tee -->|preview| sink["BufferSinkBlock (RGBA)"];
    sink --> view["VisioForgeVideoView (Texture2D)"];
    tee -->|record| mp4["MP4OutputBlock (H264 + AAC)"];
    mic[SystemAudioSourceBlock] -->|record| mp4;

_pipeline = new MediaBlocksPipeline();

// Capture sources
var cameras = await DeviceEnumerator.Shared.VideoSourcesAsync();
var videoSource = new SystemVideoSourceBlock(new VideoCaptureDeviceSourceSettings(cameras[cameraIndex]));

var mics = await DeviceEnumerator.Shared.AudioSourcesAsync();
var audioSource = new SystemAudioSourceBlock(mics[0].CreateSourceSettings());

// Preview: tightly packed RGBA frames into the Unity view
var videoSink = new BufferSinkBlock(VideoFormatX.RGBA);
videoSink.OnVideoFrameBuffer += _videoView.OnFrameBuffer;

// Record: H.264 video + AAC audio muxed to MP4
var mp4 = new MP4OutputBlock(outputPath);

// Tee the camera video to both the preview sink and the recording
var videoTee = new TeeBlock(2, MediaBlockPadMediaType.Video);
_pipeline.Connect(videoSource, videoTee);

// Preview branch — one tee output to the buffer sink
_pipeline.Connect(videoTee.Outputs[0], videoSink.Input);

// Record branch — MP4OutputBlock has no fixed inputs; call CreateNewInput once per stream
_pipeline.Connect(videoTee.Outputs[1], mp4.CreateNewInput(MediaBlockPadMediaType.Video));
_pipeline.Connect(audioSource.Output, mp4.CreateNewInput(MediaBlockPadMediaType.Audio));

await _pipeline.StartAsync();             // preview + recording both run

MP4OutputBlock starts with no input pads — each CreateNewInput(MediaBlockPadMediaType.Video|Audio) call adds a typed input wired to the internal H.264 / AAC encoder, so create exactly one per stream. BufferSinkBlock.OnVideoFrameBuffer has the same VisioForgeVideoView.OnFrameBuffer signature as the engine's OnVideoFrameUnity, so the same view renders the preview. Drop the videoTee / MP4OutputBlock / audio branch to preview only; or use the high-level VideoCaptureCoreX path above, which lets you start and stop recording at runtime without rebuilding the pipeline. This low-level path uses the same device source as the engine, so local-camera capture has the same Windows / macOS scope.

Per-platform Build Settings¶

Frequently Asked Questions¶

How do I record to a file?¶

The sample pre-registers an MP4Output and toggles capture with StartCaptureAsync(0, path) / StopCaptureAsync(0), so the live preview runs whether or not you are recording.

Can I capture from a local camera on Android or iOS?¶

Not in this release. Use the IP / RTSP camera sample on mobile — VideoCaptureCoreX over RTSP works on all four platforms. Local device capture on Android/iOS is planned for a future package.

How do I pick a specific camera?¶

Set Camera Index to the device's position in DeviceEnumerator.Shared.VideoSourcesAsync().

Which encoders does it record with?¶

MP4Output defaults to H.264 video + AAC audio. Adjust the MP4Output settings for custom encoders.

See Also¶

• Using VisioForge in Unity — package overview, setup, and how rendering works
• View an IP / RTSP camera in Unity — VideoCaptureCoreX over RTSP (all platforms)
• Play media in Unity with MediaPlayerCoreX — the high-level player sample
• Edit and render in Unity — the VideoEditCoreX timeline sample