Skip to main content

Interface: Frame

A single frame, as seen by the camera. This is backed by a C++ HostObject wrapping the native GPU buffer. At a 4k resolution, a raw Frame can be 12MB in size.

Example

const frameProcessor = useFrameProcessor((frame) => {
  'worklet'
  console.log(`Frame: ${frame.width}x${frame.height} (${frame.pixelFormat})`)
}, [])

Hierarchy​

Properties​

bytesPerRow​

• Readonly bytesPerRow: number

Returns the amount of bytes per row.

Defined in​

types/Frame.ts:33

height​

• Readonly height: number

Returns the height of the frame, in pixels.

Defined in​

types/Frame.ts:29

isMirrored​

• Readonly isMirrored: boolean

Returns whether the Frame is mirrored (selfie camera) or not.

Defined in​

types/Frame.ts:41

isValid​

• Readonly isValid: boolean

Whether the underlying buffer is still valid or not. A Frame is valid as long as your Frame Processor (or a runAsync(..) operation) is still running

Defined in​

types/Frame.ts:21

orientation​

• Readonly orientation: Orientation

Represents the orientation of the Frame, relative of what the desired output orientation is.

For example, if the phone is held in 'portrait' mode and the Frame's orientation is 'landscape-left', it is 90° rotated relative to the phone's rotation.

To make the frame appear up-right, one would need to counter-rotate it by 90°. Such counter-rotations should not actually rotate pixels in the buffers, but instead be handled via flags or transforms to avoid any performance overheads.

For example in MLKit, the caller just needs to pass the Frame's orientation to it's detect(...) function and it will interpret buffers in that target orientation.

See

See "Orientation"

Defined in​

types/Frame.ts:61

pixelFormat​

• Readonly pixelFormat: PixelFormat

Represents the pixel-format of the Frame.

Defined in​

types/Frame.ts:65

planesCount​

• Readonly planesCount: number

Returns the number of planes this frame contains.

Defined in​

types/Frame.ts:37

timestamp​

• Readonly timestamp: number

Returns the timestamp of the Frame relative to the host sytem's clock.

Defined in​

types/Frame.ts:45

width​

• Readonly width: number

Returns the width of the frame, in pixels.

Defined in​

types/Frame.ts:25

Methods​

getNativeBuffer​

â–¸ getNativeBuffer(): NativeBuffer

Get the native platform buffer of the Frame.

  • On Android, this is a AHardwareBuffer*
  • On iOS, this is a CVPixelBufferRef

The native buffer needs to be manually deleted using NativeBuffer.delete(), and this Frame needs to be kept alive as long as-, or longer than the NativeBuffer.

Returns​

NativeBuffer

Defined in​

types/Frame.ts:106

toArrayBuffer​

â–¸ toArrayBuffer(): ArrayBuffer

Get the underlying data of the Frame as a uint8 array buffer.

The format of the buffer depends on the Frame's pixelFormat.

Note that Frames are allocated on the GPU, so calling toArrayBuffer() will copy from the GPU to the CPU.

Returns​

ArrayBuffer

Example

const frameProcessor = useFrameProcessor((frame) => {
  'worklet'

  if (frame.pixelFormat === 'rgb') {
    const buffer = frame.toArrayBuffer()
    const data = new Uint8Array(buffer)
    console.log(`Pixel at 0,0: RGB(${data[0]}, ${data[1]}, ${data[2]})`)
  }
}, [])

Defined in​

types/Frame.ts:87

toString​

â–¸ toString(): string

Returns a string representation of the frame.

Returns​

string

Example

console.log(frame.toString()) // -> "3840 x 2160 Frame"

Defined in​

types/Frame.ts:95