Stream templates¶

Once you have dozens of streams, nobody wants to retype the same transcoder and archive settings into each one. A template is a set of defaults for stream config sections. A stream points at one template, and the template's sections apply wherever the stream has none of its own.

A template is not a schedule and not a group: it starts nothing and owns no streams. All it does is supply values to the streams that pointed at it.

Which sections a template defines¶

A template can define six config sections, and only those:

• Transcoder — ladder, presets, audio rules, GOP; see Transcoding and MBR.
• DVR — archive recording: depth, disks, retention; see Archive (DVR).
• Thumbnails — see Thumbnails.
• Source timeouts — behaviour when an input goes away; see Input failover.
• Live window — the length of the live window in segments.
• Speech to text — the section exists in the template contract, but the console has no form for it yet: it cannot be set through the interface.

Everything else — sources, the name, the reference to an authorization backend — a template does not define: those are properties of a particular stream.

The resolution rule: an own section wins whole¶

There is no field-by-field merge. A section is taken whole: if the stream has its own transcoder section, not a single field of the template's one applies. If it has none, the template's section is in force.

Two practical consequences follow:

• To change one field relative to the template, the stream has to carry the entire section — the rest of its fields included.
• An empty section and a missing section are the same thing. An empty thumbnail list and null both count as undefined, and the template takes over in their place.

A reference to a template that does not exist is equivalent to no reference at all: the stream runs on its own sections. The stream page says so — Template {name} does not exist.

The template list¶

The Templates screen holds every template of the installation. Type a name into New Template Name and press Create. The Sections column shows which sections the template actually defines — an empty template affects nothing.

Deleting a template that something still references is rejected: Cannot delete: streams still reference this template. Clear the reference on them first. This guards against silently losing the settings of dozens of streams at once.

The template page¶

The tabs mirror the sections: Transcoder, DVR, Thumbnails, Source timeouts (which also carries the Live window field) and Streams using this template.

The forms are the same ones as on the stream page, with one caveat: a template has no input by definition. The transcoder ladder is edited without hints from the source tracks, and there is no input preview or substitution from a real feed — there is nowhere to take it from.

A dot on a tab means unsaved edits in that section. Save and Cancel behave as on the stream page: Save is active only while there are unsaved edits, Cancel rolls back to the accepted baseline.

The Streams using this template tab lists the referencing streams; on a long list it says that the first N are shown. Look at it before editing: editing a template changes the behaviour of all those streams at once.

The template seen from a stream¶

The template is chosen on the stream's basic settings tab with the Template field (No template clears the reference). The stream list has a Template column.

Every section on the stream page is in one of four states:

• Own — the section is set on the stream and the template does not define it.
• From template {name} — there is no own section, so the template's one is in force. Shown read-only.
• Overrides template {name} — the section is set in both places, and the stream's one wins. This state is called out deliberately: otherwise a conscious departure from the template is indistinguishable from a stream that knows nothing about templates.
• Empty — neither the stream nor the template defines the section.

Two buttons switch the state:

• Override — copies the template's section into the stream and makes it editable. The section becomes overriding.
• Revert to template — deletes the stream's own section, and the template's one is in force again.

The stream list and the columns that read sections — transcoder, DVR, input failover — show the effective values, that is with the template already substituted, not the raw stream document.