VideoSource

Video source

General class of video capture objects providing functionality to grab images from various sources. It implements basic interfaces like setup, start, stop of the video capture, and grabbing of frames. Internally utilizes ImageBuffer as storages.

Extends

• EventEmitterT<CaptureEvents>

Extended by

• VideoCapture
• ImageCapture

Constructors

new VideoSource()

new VideoSource(): VideoSource

Constructor

Returns

VideoSource

Overrides

EventEmitterT.constructor

Properties

buffer

buffer: ImageBuffer

Context of original stream

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captureTime

captureTime: number = 0

Timestamp of the last captured frame

---

clipRect?

protected optional clipRect: ClipRect

Clipping rectangle

---

sizeMax?

protected optional sizeMax: number

Maximum capture resolutions

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transpose?

protected optional transpose: boolean

Transpose frames

Methods

addListener()

addListener<E>(event, listener): this

Adds the listener function to the end of the listeners array

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.addListener

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capture()

capture(): boolean

Grab the next video frame

VideoSource grabs the static image permanently stored in embedded ImageBuffer object.

Returns

boolean

True if next frame was available and grabbed

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dispose()

dispose(): void

Dispose video source object

Returns

void

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emit()

emit<E>(event, …args): boolean

Synchronously calls each of the listeners registered for the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• …args: Args<CaptureEvents[E]>

Arguments passed to the listeners

Returns

boolean

True if the event had listeners, False otherwise

Inherited from

EventEmitterT.emit

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eventNames()

eventNames(): (string | symbol)[]

List of emitter’s events

Returns

(string | symbol)[]

List of emitter’s events

Inherited from

EventEmitterT.eventNames

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getMaxListeners()

getMaxListeners(): number

Maximum number of listeners per event

Returns

number

Maximum number of listeners per event

Inherited from

EventEmitterT.getMaxListeners

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listenerCount()

listenerCount<E>(event): number

The number of listeners listening to the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

Returns

number

Number of listeners

Inherited from

EventEmitterT.listenerCount

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listeners()

listeners<E>(event): Function[]

Copy of the array of listeners for the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.listeners

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off()

off<E>(event, listener): this

Removes the listener from the listener array for the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.off

---

on()

on<E>(event, listener): this

Adds the listener function to the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.on

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once()

once<E>(event, listener): this

Adds a one-time listener function for the event

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.once

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pause()

pause(): void

Pause video capture

Returns

void

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prependListener()

prependListener<E>(event, listener): this

Adds the listener function to the beginning of the listeners array

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.prependListener

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prependOnceListener()

prependOnceListener<E>(event, listener): this

Adds a one-time listener function to the beginning of the listeners array

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

Inherited from

EventEmitterT.prependOnceListener

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ratio()

ratio(): number

Aspect ratio of the video stream

Returns

number

Aspect ratio of the video stream

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rawListeners()

rawListeners<E>(event): Function[]

Copy of the array of listeners for the event including wrappers

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.rawListeners

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removeAllListeners()

removeAllListeners<E>(event?): this

Removes all listeners, or those of the specified event

Type Parameters

• E extends "resize"

Parameters

• event?: E

The name of the event

Returns

this

This EventEmitter

Inherited from

EventEmitterT.removeAllListeners

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removeListener()

removeListener<E>(event, listener): this

Removes the specified listener from the listener array

Type Parameters

• E extends "resize"

Parameters

• event: E

The name of the event

• listener: CaptureEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.removeListener

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reset()

reset(): void

Reset video capture

After reset() capture may be started again only after setup().

Returns

void

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setMaxListeners()

setMaxListeners(n): this

Sets maximum number of listeners per event

Parameters

• n: number

Maximum number of listeners

Returns

this

This EventEmitter

Inherited from

EventEmitterT.setMaxListeners

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setup()

setup(params?): Promise<boolean>

Setup video source

Sets up capture, overridden for particular video source. Video source can be setup by simplified VideoParams opening default front/rear camera with provided resolution, custom MediaStreamConstraints providing the most flexible way to setup video stream (e.g. set deviceId), or external MediaStream allowing custom video sources (e.g. from file). Video source can also be a media file provided by url or FileParams that additionally allows to set maximum capture size in cases resolution is too big for a device. Default implementation sets video resolution according to size in VideoParams or 1920x1080 as the fallback. It captures static image, canvas is filled by white color.

Parameters

• params?: VideoSourceParams

Parameters of video capture

Returns

Promise<boolean>

Promise resolved to the status of setup when done

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size()

size(): Size

Resolution of the video stream

Returns

Size

Resolution of the video stream

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start()

start(): Promise<void>

Start video capture

Video capture can be started only after successful setup().

Returns

Promise<void>

Promise resolved when capture is started

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updateSize()

protected updateSize(size): void

Update callback on video resize

Parameters

• size: Size

New size of the video stream

Returns

void