useFrameOutput

function useFrameOutput(__namedParameters: UseFrameOutputProps): CameraFrameOutput

Use a CameraFrameOutput.

The onFrame(...) callback will be called for every Frame the Camera sees. It is a synchronous JS function running on the CameraFrameOutput's thread - aka a "worklet".

Discussion

You must dispose the Frame after your Frame Processor has finished processing, otherwise subsequent Frames may be dropped (see onFrameDropped(...)).

Discussion

Choosing an appropriate pixelFormat depends on your Frame Processor's usage. While the most commonly used format in visual recognition models is 'rgb', it is by far not the most efficient format for a Camera pipeline as it requires an additional conversion and uses ~2.6x more bandwidth than 'yuv'.

If you render to native Surfaces (e.g. via GPU pipelines or Media Encoders), you may also be able to use 'native', which chooses whatever the currently selected CameraFormat's nativePixelFormat is, and requires zero conversions. Use 'native' with caution, as your CameraFormat's nativePixelFormat might also be a RAW format like 'raw-bayer-packed96-12-bit', or a vendor-specific private format ('private').

Examples:

• MLKit natively supports YUV, so streaming in 'yuv' is most efficient.
• OpenCV natively supports YUV, so streaming in 'yuv' is most efficient.
• LiteRT supports YUV, but converts to RGB internally - so streaming in 'rgb' directly is more efficient as conversion is handled in the Camera pipeline.
• react-native-skia supports both YUV and RGB, so streaming in 'yuv' is more efficient.

See

• TargetVideoPixelFormat
• VideoPixelFormat

Example

const frameOutput = useFrameOutput({
  onFrame(frame) {
    'worklet'
    // some frame processing
    frame.dispose()
  }
})