Continuum Timeline Export

Here's the mistake this node invites, and the pack author has clearly been bitten by it: you build a lovely cut in Timeline Studio, find the export button, export a movie, then feed that movie back in as H3 guidance. Which throws away source timing, re-encodes your footage and costs you an hour. The node's own description says it plainly - H3 guidance travels through Timeline Project and Continuum Timeline Sampler, not through an exported movie.

So: Continuum Timeline Export is for getting a finished file out. Not for influencing a generation.

What it is

A terminal node. It takes the typed timeline project, renders the project's saved Render [in,out) selection through the composition, and writes a file into ComfyUI's output directory named Timeline_<project_id>_<8-hex>.<ext>. It returns the path as a STRING on output_file, and it's flagged as an output node, so it runs when you hit Queue even if nothing downstream consumes it.

Because it's a real output node, ComfyUI's cache logic treats it as a reason to walk the graph backwards and execute what it needs. That also means: if you're iterating on prompts and this node is still in the graph, you're re-rendering a movie every queue. Bypass or mute it while you work.

Inputs that matter

Required are timeline (the H3_CONTINUUM_TIMELINE_PROJECT socket from Timeline Studio) and format, which is just two choices:

• lossless → FFV1 in MKV, bgr0 pixels plus 32-bit float PCM. Pixel- and sample-preserving after whatever scaling and time-sampling the composition already declared. This is the archival option, and files get large fast.
• h264 → libx264 at CRF 16 with AAC audio in MP4, +faststart, yuv420p. A distribution re-encode. Never bit-exact, and it will refuse odd dimensions.

The optional resolution decides how many pixels you get, and the tooltip is the whole story: timeline uses the H3 sampling canvas; source uses native source pixel dimensions with composition re-encoding. Source mode is the one people get wrong - it needs one unambiguous visible video clip in the export range to take its geometry from. Two clips at different native sizes in one range and it stops with "Multiple source resolutions" rather than picking one for you. Highlight a single clip, or explicitly choose timeline.

One honest caveat from the pack's own notes: a "source" export is still an 8-bit RGB re-encode. You're getting original dimensions, not the original bitstream.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/xmarre/ComfyUI-H3-Continuum-Plus.git ComfyUI-H3-Continuum

then restart. Manager users: search H3 Continuum. Two real dependencies for this node specifically - the pack's requirements.txt pins av>=17.0.0 (PyAV), and the encoder path shells out through PyAV, so install into ComfyUI's own Python environment if its bundled PyAV is older. ffmpeg and ffprobe also need to be on the server's PATH; Timeline Studio's media probing and the Save Take muxer call them directly. On Windows there's install_windows.ps1 in the repo, which copies the checkout into a target ComfyUI/custom_nodes/ComfyUI-H3-Continuum, backs up any existing install, and pip-installs requirements.

Don't install this next to the upstream ukr8b3g-cmyk/ComfyUI-H3-Continuum - overlapping node identifiers, one install at a time.

Troubleshooting

H.264 refuses your project. "H.264 yuv420p requires even source dimensions" is literal. If you exported at source resolution from a clip with an odd width, you get FFV1 or nothing. Round the canvas, or pick FFV1.

"Not enough disk space for sample-exact export audio." The lossless path caches decoded PCM for the whole range before encoding, and it checks free space up front rather than dying at 80%. Export a shorter range, or free space in the output volume. Whole-stream PCM caching being off by default is a deliberate memory/disk trade, and repeated late-source seeks are the visible cost.

The export is refused because of a stale take. Composition won't silently emit generated footage it can't vouch for. Accept a compatible alternative, or rerender the dependent suffix in Studio.

You exported and H3 still ignored your footage. Right - it always would have. In Studio, select the retained clip and use Guide H3 with selected clip, then Queue selection. The video-guidance track references the registered source media and its source-in PTS/speed; nothing is exported or re-imported on that path. Think of Export as the printer and the guidance track as the brief.