Protoface Pika 2.2 Transition

Pika 2.2's transition operation takes a stack of stills and animates between them, which means the number of transitions is never the number of images - it's one fewer. This helper node holds a single transition: how long it lasts, and optionally what it should be. Two fields, and a set of constraints that will reject your graph before you're charged if you get the count wrong.

What it's for

The Pika 2.2 model node in this pack has a transitions list control. You switch it to Set, connect one Protoface Pika 2.2 Transition helper per gap, and the pack assembles the list from your items in order. The same generated-helper pattern the pack uses for Kling shots and Aleph keyframe positions: a small typed node per list entry, with its own socket type so it can only ever land in the right list.

The two fields

duration is a FLOAT, default 5, minimum 5, maximum 25, step 0.1. So you can ask for a 7.3-second crossfade but not a 2-second one - the API's floor is 5.

prompt is optional and sits in Default/Set mode. Default means the field is omitted from the request and the transition inherits the global prompt on the Pika node. Set it to override per transition: "the camera whips right and the scene becomes a snowfield" for gap one, something else for gap two. That per-gap prompt is the whole reason transitions are list items rather than one global setting.

The output is value_out, typed PROTOFACE_VALUE_02e373ae03962e76 - a digest of this exact item schema, so it fits Pika 2.2's transitions control and nothing else.

The constraints, which are the real content here

The pack validates before upload, so these fail fast rather than costing credits:

• One transition per gap. The list length must equal len(images) - 1. Three stills means two transitions. Not three.
• Twenty-five seconds total, across all transitions. Three 10-second transitions is 30, and that's over budget even though each one is individually legal.
• Five images max, so five transitions max.

Nothing enforces a minimum - leave the control on Default and you get the API's default five-second transitions using the global prompt, which is a perfectly good way to test the idea before you start designing each gap.

The other thing to internalise: Pika's pricing is per output second at roughly 20 credits, and transition durations are output seconds. Total your transitions plus the rest of the clip length before queueing, or a five-image chain quietly becomes an expensive one.

Inputs and outputs, plainly

• duration (FLOAT, 5–25): how long this gap takes.
• prompt (STRING, optional): per-transition override.
• value_out (typed PROTOFACE_VALUE_02e373ae03962e76): into Pika 2.2's transitions list.

It's not an output node, it makes no API call, and it needs no key of its own.

Install

Ships with the pack:

cd ComfyUI/custom_nodes
git clone --branch v0.1.0 --depth 1 https://github.com/protoface-ai/protoface-comfyui.git protoface
python -m pip install -r protoface/requirements.txt

or Manager → Protoface → protoface-nodes → restart → reload the browser. ComfyUI 0.41.0+, Python 3.10+, pip with ComfyUI's interpreter. The Pika node downstream needs an API key from the Protoface panel in the lower right (or PROTOFACE_API_KEY); the helper itself doesn't.

Where people get stuck

Off-by-one counts. The single most common wiring mistake with this node: four images with four transitions, which fails length validation. Count your gaps, not your pictures.

Item ordering. The pack numbers autogrow sockets item_1, item_2, … and sorts numerically, so the helper on item_1 is the transition from image 1 to image 2. Keep that mapping stable while you edit durations, or you'll tune the wrong gap.

Same-name helper confusion. The pack has several "Structured Controls" helpers of similar shape. If the socket won't connect to transitions, you grabbed a Kling shot or an Aleph keyframe position instead. The type name tells you: only PROTOFACE_VALUE_02e373ae03962e76 is Pika 2.2's.