Video Compose

Overlays multiple videos on top of a primary reference stream

Component Configuration

Option Description Required Environment override

Option	Description	Required	Environment override
id	A unique identifier for the component instance	✓
displayName	The name shown in the Studio UI of this component	✓
preview	How this component's two preview monitors are delivered. A STREAMED preview needs H264, so Norsk creates an encoder for it automatically — and because that encoder belongs to this component, if it cannot keep up it back-pressures the whole workflow, not just the preview. A 1080p50 stream preview can therefore throttle your programme output. Use a lower frame rate, JPEG stills, or off if you do not need a live monitor. Does not affect the per-source thumbnails.	✓
thumbnailResolution	Resolution of the per-source thumbnails used to draw the layout diagram (the 'Current Layout' pane and the preset previews). These are PNG stills, one per source per second, so a source with transparency keeps its alpha and does not hide the layers beneath it. Larger is sharper but pushes bigger stills to every open browser pane. (default: "480x270")	✗
previewTransport	Deprecated — superseded by the Preview setting.	✓
sources	Automaticaly maintained by component, list of the sources that are subscribed to	✓
reference	Source name (NOT component id) of the reference stream that will drive the output. For input.srt-listener, this is the connection's streamId, which may differ from the component id.	✗
pixelFormat	Pixel format of the composed output. Leave unset and the engine composes to 4:2:0 8-bit whatever the reference carries — a 4:2:2 or 10-bit reference is subsampled back here. Pick 4:2:2 / 4:4:4 to keep chroma, or a 10-bit format to keep precision, through the composition. Software path only.	✗
hardwareAcceleration	Override the global hardware acceleration setting	✗	`<COMPONENT_ID>_HARDWAREACCELERATION`
pipelineHints	Quadra-only hardware pipeline hints (ignored on other hardware)	✗
notes	Notes about this component	✗

A unique identifier for the component instance

✓

displayName

The name shown in the Studio UI of this component

✓

preview

How this component's two preview monitors are delivered. A STREAMED preview needs H264, so Norsk creates an encoder for it automatically — and because that encoder belongs to this component, if it cannot keep up it back-pressures the whole workflow, not just the preview. A 1080p50 stream preview can therefore throttle your programme output. Use a lower frame rate, JPEG stills, or off if you do not need a live monitor. Does not affect the per-source thumbnails.

✓

thumbnailResolution

Resolution of the per-source thumbnails used to draw the layout diagram (the 'Current Layout' pane and the preset previews). These are PNG stills, one per source per second, so a source with transparency keeps its alpha and does not hide the layers beneath it. Larger is sharper but pushes bigger stills to every open browser pane. (default: "480x270")

✗

previewTransport

Deprecated — superseded by the Preview setting.

✓

sources

Automaticaly maintained by component, list of the sources that are subscribed to

✓

reference

Source name (NOT component id) of the reference stream that will drive the output. For input.srt-listener, this is the connection's streamId, which may differ from the component id.

✗

pixelFormat

Pixel format of the composed output. Leave unset and the engine composes to 4:2:0 8-bit whatever the reference carries — a 4:2:2 or 10-bit reference is subsampled back here. Pick 4:2:2 / 4:4:4 to keep chroma, or a 10-bit format to keep precision, through the composition. Software path only.

✗

hardwareAcceleration

Override the global hardware acceleration setting

✗

<COMPONENT_ID>_HARDWAREACCELERATION

pipelineHints

Quadra-only hardware pipeline hints (ignored on other hardware)

✗

notes

Notes about this component

✗

Options with an environment override can be set when Studio starts, without editing the workflow. <COMPONENT_ID> is this component’s id in your workflow, uppercased, with spaces and dashes replaced by underscores and other punctuation removed — a component named SRT Input reads SRT_INPUT_PORT. Renaming a component changes its id, and so changes these variable names.

Preview (Off (no preview monitors))

Option	Description	Required
type	"off"	✓

Option

Description

Required

type

"off"

✓

Preview (JPEG stills (1 fps, cheapest))

Option	Description	Required
type	"jpeg"	✓

Option

Description

Required

type

"jpeg"

✓

Preview (Live stream)

Option	Description	Required
type	"stream"	✓
transport	WebRTC serves the monitors over WHEP; MoQ serves them over WebTransport instead, and requires the global MoQ Preview listener (cert + key) to be configured. (default: "webrtc")	✗
frameRate	Frame rate of the preview stream. 'Source rate' is the most expensive — a 1080p50 compose gets a 1080p50 preview encode. A lower rate cuts that encoder's work proportionally. (default: {"type":"source"})	✗
resolution	Resolution of the preview stream. 'Source resolution' encodes at the compose's full output size — a 1080p encode feeding a monitor a few hundred pixels wide. Encoder cost scales with pixel count, so this is usually a bigger saving than the frame rate, and the preview encoder does the resize itself at no extra cost. (default: {"type":"source"})	✗

Option

Description

Required

type

"stream"

✓

transport

WebRTC serves the monitors over WHEP; MoQ serves them over WebTransport instead, and requires the global MoQ Preview listener (cert + key) to be configured. (default: "webrtc")

✗

frameRate

Frame rate of the preview stream. 'Source rate' is the most expensive — a 1080p50 compose gets a 1080p50 preview encode. A lower rate cuts that encoder's work proportionally. (default: {"type":"source"})

✗

resolution

Resolution of the preview stream. 'Source resolution' encodes at the compose's full output size — a 1080p encode feeding a monitor a few hundred pixels wide. Encoder cost scales with pixel count, so this is usually a bigger saving than the frame rate, and the preview encoder does the resize itself at no extra cost. (default: {"type":"source"})

✗

Pipeline Hints

Option	Description	Required
type		✓
rescaler	Quadra rescaler algorithm (ffmpeg ids: 0=default, 1=filterblit, 2=bicubic) (default: "default")	✗

Option

Description

Required

type

✓

rescaler

Quadra rescaler algorithm (ffmpeg ids: 0=default, 1=filterblit, 2=bicubic) (default: "default")

✗

Global Configuration

Moq Preview

Environment override: GLOBAL_MOQ_PREVIEW (sets this global option as a whole).

Option	Description	Required
quicServerPort	QUIC listener port for native MoQT subscribers (optional — only needed for non-browser clients)	✗
webTransportPort	WebTransport listener port for browser MoQ players. Defaults to 4443. (default: 4443)	✗
publicHost	The hostname browsers reach MoQ on, when it is not the public hostname (PUBLIC_URL_PREFIX): e.g. a host whose web UI is reached over an SSH tunnel while its media ports are public. Applies to the listener above and, when no Relay public URL is set, to the relay.	✗
quicServerCert	TLS certificate file path. If omitted, a self-signed cert is auto-generated (14-day validity, rotated every 10 days).	✗
quicServerKey	TLS private key file path. If omitted, auto-generated alongside the cert.	✗
serveFingerprint	Publishes the cert SHA-256 so the moq-js player can trust it via WebTransport's serverCertificateHashes. Defaults on. Turn it off when the certificate is CA-issued and the browser trusts it already. (default: true)	✗
relayUrl	Publish through a shared MoQ relay instead of binding a listener here. Setting this switches every MoQ component to relay mode and the ports/cert above are no longer used, so several Norsk instances on one host can share a single MoQ port. This is how NORSK reaches the relay, which behind a proxy is an internal address.	✗
relayPublicUrl	What the BROWSER connects to, if that differs from the Relay URL. Leave blank to use the public hostname (PUBLIC_URL_PREFIX) with the Relay URL's port.	✗
relayNamespacePrefix	Prepended to every namespace this instance publishes to the relay, so instances sharing one relay stay distinct. Usually the instance name.	✗
relayDisableTlsVerify	Skip TLS verification when connecting to the relay. Needed only for a relay with a self-signed certificate. (default: false)	✗

Option

Description

Required

quicServerPort

QUIC listener port for native MoQT subscribers (optional — only needed for non-browser clients)

✗

webTransportPort

WebTransport listener port for browser MoQ players. Defaults to 4443. (default: 4443)

✗

publicHost

The hostname browsers reach MoQ on, when it is not the public hostname (PUBLIC_URL_PREFIX): e.g. a host whose web UI is reached over an SSH tunnel while its media ports are public. Applies to the listener above and, when no Relay public URL is set, to the relay.

✗

quicServerCert

TLS certificate file path. If omitted, a self-signed cert is auto-generated (14-day validity, rotated every 10 days).

✗

quicServerKey

TLS private key file path. If omitted, auto-generated alongside the cert.

✗

serveFingerprint

Publishes the cert SHA-256 so the moq-js player can trust it via WebTransport's serverCertificateHashes. Defaults on. Turn it off when the certificate is CA-issued and the browser trusts it already. (default: true)

✗

relayUrl

Publish through a shared MoQ relay instead of binding a listener here. Setting this switches every MoQ component to relay mode and the ports/cert above are no longer used, so several Norsk instances on one host can share a single MoQ port. This is how NORSK reaches the relay, which behind a proxy is an internal address.

✗

relayPublicUrl

What the BROWSER connects to, if that differs from the Relay URL. Leave blank to use the public hostname (PUBLIC_URL_PREFIX) with the Relay URL's port.

✗

relayNamespacePrefix

Prepended to every namespace this instance publishes to the relay, so instances sharing one relay stay distinct. Usually the instance name.

✗

relayDisableTlsVerify

Skip TLS verification when connecting to the relay. Needed only for a relay with a self-signed certificate. (default: false)

✗

Tags: compose overlay pip picture-in-picture layout