lib/stream-stats

What a dashboard shows of the session, gathered in one place for both cores and published on window under one contract.

window.stream_info is what the server said of the stream: the capture path and whether it is zero-copy, the encoder and whether it is hardware, the GPU, and the reason a faster path was declined (stream_stats.py on the server). It arrives once and again on a change, whether or not anybody looks. window.stream_client is this page's half: the transport and the path it took, the codec and resolution, and the decoder with the evidence for calling it hardware or software.

Everything that moves is gathered only while a dashboard has its stats on screen. It says so with a statsOpen window message; the collector then asks the server for stream_stats (the _stats verb), the core samples its own side once a second, and each second's figures land in window.stream_stats: latest, and history, which starts empty when the stats open and grows while they stay open, up to HISTORY_MAX seconds. Shut, nothing is sampled, nothing is sent and the server sends nothing. A shared viewer never subscribes.

Classes

StreamStats

Defined in: lib/stream-stats.js:138

Constructors

Constructor

new StreamStats(options): StreamStats;

Defined in: lib/stream-stats.js:145

Parameters

Parameter	Type	Description
`options`	{ `transport`: `"webrtc"` \| `"websockets"`; `send`: (`arg0`) => `void`; `isViewer`: () => `boolean`; `onOpenChange`: (`arg0`) => `void`; }	`send` puts one text message on the session connection; `onOpenChange` lets the core start and stop its own sampling.
`options.transport`	`"webrtc"` \| `"websockets"`	-
`options.send`	(`arg0`) => `void`	-
`options.isViewer`	() => `boolean`	-
`options.onOpenChange`	(`arg0`) => `void`	-

Returns

StreamStats

Accessors

open

Get Signature

get open(): boolean;

Defined in: lib/stream-stats.js:165

Whether a dashboard has its stats on screen.

Returns

boolean

Methods

setOpen()

setOpen(open): void;

Defined in: lib/stream-stats.js:173

A dashboard opened or shut its stats. Opening starts a fresh history.

Parameters

Parameter	Type	Description
`open`	`boolean`	-

Returns

void

subscribe(): void;

Defined in: lib/stream-stats.js:185

Tells the server what this page wants; a fresh connection has to be told again.

Returns

void

disconnected()

disconnected(): void;

Defined in: lib/stream-stats.js:197

The connection went away, and the subscription with it.

Returns

void

setInfo()

setInfo(info): void;

Defined in: lib/stream-stats.js:202

Parameters

Parameter	Type	Description
`info`	`StreamInfo`	The server's `stream_info`.

Returns

void

setClient()

setClient(description): void;

Defined in: lib/stream-stats.js:207

Parameters

Parameter	Type	Description
`description`	`Partial`<`StreamClient`>	What the core learned of its own side.

Returns

void

serverSample()

serverSample(stats): void;

Defined in: lib/stream-stats.js:212

Parameters

Parameter	Type	Description
`stats`	{ }	The server's `stream_stats`.

Returns

void

noteBytes()

noteBytes(bytes): void;

Defined in: lib/stream-stats.js:218

Parameters

Parameter	Type	Description
`bytes`	`number`	Stream bytes that arrived, for the bandwidth figure.

Returns

void

clientSample()

clientSample(figures): void;

Defined in: lib/stream-stats.js:227

One second's figures from the core, merged with the server's and appended to the history. mbps comes from noteBytes unless the core measured it.

Parameters

Parameter	Type	Description
`figures`	{ }	-

Returns

void

Variables

HISTORY_MAX

const HISTORY_MAX: 600 = 600;

Defined in: lib/stream-stats.js:32

Seconds of history kept for the graphs.

SERVER_FRESH_MS

const SERVER_FRESH_MS: 3000 = 3000;

Defined in: lib/stream-stats.js:34

Server figures older than this are left out of a sample, in ms.

Functions

decoderOfFormat()

function decoderOfFormat(format): "hardware" | "software" | "unknown";

Defined in: lib/stream-stats.js:92

What a decoded frame's pixel format says of the decoder behind it. A hardware decoder hands out NV12 or an opaque frame, a software one planar I4xx.

Parameters

Parameter	Type	Description
`format`	`string`	`VideoFrame.format`; undefined where no frame was seen.

Returns

"hardware" | "software" | "unknown"

webcodecsDecoder()

function webcodecsDecoder(evidence): object;

Defined in: lib/stream-stats.js:107

The WebCodecs decoder verdict from everything the page can know: a software preference is certain, an engine that refuses the stream's configuration with hardware required has none, and otherwise the frames say which kind made them.

Parameters

Parameter	Type	Description
`evidence`	{ `forcedSoftware`: `boolean`; `hardwareSupported`: `boolean`; `format`: `string`; }	`hardwareSupported` is `VideoDecoder.isConfigSupported` with `prefer-hardware`, null where unasked.
`evidence.forcedSoftware`	`boolean`	-
`evidence.hardwareSupported`	`boolean`	-
`evidence.format`	`string`	-

Returns

object

decoder

decoder: "hardware" | "software" | "unknown";

decoder_evidence

decoder_evidence: string;

webrtcDecoder()

function webrtcDecoder(evidence): object;

Defined in: lib/stream-stats.js:124

The WebRTC decoder verdict from the inbound video report. Engines name the decoder only to a page that holds a capture permission, so without one the verdict falls back to whether the engine has an efficient decoder at all.

Parameters

Parameter	Type	Description
`evidence`	{ `implementation`: `string`; `powerEfficient`: `boolean`; `capable`: `boolean`; }	`capable` is `MediaCapabilities.decodingInfo().powerEfficient` for the stream.
`evidence.implementation`	`string`	-
`evidence.powerEfficient`	`boolean`	-
`evidence.capable`	`boolean`	-

Returns

object

decoder

decoder: "hardware" | "software" | "unknown";

decoder_evidence

decoder_evidence: string;

lib/stream-stats

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