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

Constructors

Constructor

new VideoSource(): VideoSource

Constructor

Returns

VideoSource

Overrides

EventEmitterT.constructor

Properties

aspectRatio?

protected optional aspectRatio: number

Aspect ratio

buffer

buffer: ImageBuffer

Context of original stream

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

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

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

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

dispose()

dispose(): void

Dispose video source object

Returns

void

emit()

emit<E>(event, …args): boolean

Synchronously calls each of the listeners registered for the event

Type Parameters

E

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

eventNames()

eventNames(): (string | symbol)[]

List of emitter’s events

Returns

(string | symbol)[]

List of emitter’s events

Inherited from

EventEmitterT.eventNames

getMaxListeners()

getMaxListeners(): number

Maximum number of listeners per event

Returns

number

Maximum number of listeners per event

Inherited from

EventEmitterT.getMaxListeners

listenerCount()

listenerCount<E>(event): number

The number of listeners listening to the event

Type Parameters

E

E extends "resize"

Parameters

event

E

The name of the event

Returns

number

Number of listeners

Inherited from

EventEmitterT.listenerCount

listeners()

listeners<E>(event): Function[]

Copy of the array of listeners for the event

Type Parameters

E

E extends "resize"

Parameters

event

E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.listeners

off()

off<E>(event, listener): this

Removes the listener from the listener array for the event

Type Parameters

E

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

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

once()

once<E>(event, listener): this

Adds a one-time listener function for the event

Type Parameters

E

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

pause()

pause(): void

Pause video capture

Returns

void

prependListener()

prependListener<E>(event, listener): this

Adds the listener function to the beginning of the listeners array

Type Parameters

E

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

prependOnceListener()

prependOnceListener<E>(event, listener): this

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

Type Parameters

E

E extends "resize"

Parameters

event

E

The name of the event

listener

CaptureEvents[E]

The callback function

Returns

this

Inherited from

EventEmitterT.prependOnceListener

ratio()

ratio(): number

Aspect ratio of the video stream

Returns

number

Aspect ratio of the video stream

rawListeners()

rawListeners<E>(event): Function[]

Copy of the array of listeners for the event including wrappers

Type Parameters

E

E extends "resize"

Parameters

event

E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.rawListeners

removeAllListeners()

removeAllListeners<E>(event?): this

Removes all listeners, or those of the specified event

Type Parameters

E

E extends "resize"

Parameters

event?

E

The name of the event

Returns

this

This EventEmitter

Inherited from

EventEmitterT.removeAllListeners

removeListener()

removeListener<E>(event, listener): this

Removes the specified listener from the listener array

Type Parameters

E

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

reset()

reset(): void

Reset video capture

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

Returns

void

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

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. Additional fine-grained MediaStreamConstraints can be passed via opts field providing the most flexible way to setup video stream (for example, by requesting specific deviceId). Stream constraints have higher priority than rest or params. Another options are an external MediaStream allowing custom video sources (e.g. remote stream) or a media file defined by url or FileParams that allows to limit 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

size()

size(): Size

Resolution of the video stream

Returns

Size

Resolution of the video stream

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

updateSize()

protected updateSize(size): void

Update callback on video resize

Parameters

size

Size

New size of the video stream

Returns

void