Movie playback and export

For data with more than one timepoint, the existing T slider provides playback, frame stepping, seeking, adjustable speed and looping. Playback defaults to 5 frames per second and does not imply an acquisition interval.

Playback holds the current channel intensity limits and slider bounds fixed. Intensity sliders, numeric limits, AUTO, FIT and HIST stay disabled throughout playback, including while the next frame loads. Statistics refresh resumes when playback pauses, finishes or is stopped by frame stepping/seeking; the selected contrast remains unchanged until the user adjusts it. This applies in 2D and 3D.

Ordinary HTTP-backed images render immediately with their OMERO source ranges, then apply sampled initial AUTO contrast once it is available. Manual ranges and contrast restored from a viewer URL are preserved. Opening an image afresh from OMERO allows the initial AUTO calculation instead of restoring a saved URL.

Export movie renders a selected frame range using the authenticated browser loaders and the current compositor. Encoding runs locally in a browser worker using WebCodecs and the bundled MP4 muxer. No new rendering service is required. Chrome is the playback acceptance target; encoding support is checked separately before starting an export. Progress and cancellation are shown beside export.

The film/download icon in the toolbar opens the export options (tooltip: Export movie). During export, a visible Cancel button remains beside the icon, including when the options panel is closed. Cancellation stops the active export and restores the controls; a late result from a cancelled export is not downloaded.

Exports support intensity channels, slice or declared Z projection, independently ordered overlapping raster-label layers, caller-supplied points and lines, and tracks with explicit table-column mappings. Track gaps remain gaps; observations are never interpolated automatically. Trails and current-position markers are bounded and use stable colors. Crops use source pixel coordinates and preserve their offsets. Scale-bar labels fit the exported panel.

Initial limits are 2000 frames, 2048 by 2048 pixels, and the smaller of 256 MiB or the caller's upload limit. Processing is sequential and decoded frames are not retained for the entire sequence. Projection loading also reduces slices incrementally rather than requesting every slice at once.

For Z projections, raster labels use the same categorical projection as the viewer: the first nonzero object ID along Z is retained at each pixel, after any focused-ID filtering. This applies to MIP, mean and minimum intensity projections; IDs are never averaged. Slice exports retain the selected Z plane.

The additive render recipe uses version: 2 and a sequence declaration with version: 1, start, end, optional step, and optional fps (default 5). In Analysis use source: {kind: "image-input"} to select a workspace Image by its OMERO ID, independently of the table supplying tracks. No workflow/result metadata is required. current-image remains an alias and explicit UUID recipes remain supported. Source access and image changes are checked again on authorization refresh. The recipe retains frame range, playback speed, crop, dimensions, channel/contrast settings, overlays, source identity and renderer provenance. Acquisition units are preserved when available; otherwise timepoints are frames.

The authenticated zarr-movie-v1 capability exposes the same renderer to OMERO.Analysis Methods and Notebooks. Their render request declares omero_analysis_render_format="mp4". Existing PNG/SVG recipes and ordinary viewer links remain supported. The bundled use-omero-zarr-viewer skill (v7) documents both formats; its canonical source is under _agents/skills/, with the packaged copy checked by scripts/sync_analysis_skills.py --check.

Rendered 3D movies

The viewer also exports Volume, Slice and Orthogonal layouts in Neuroglancer and Viv. These exports capture the current screen view with its camera, visible layers and scale bars, and fit within the same 2048 × 2048 limit. They are not native-resolution 3D stacks. Neuroglancer can include label surfaces; Viv renders intensities. Export waits for each frame, permits cancellation and restores the original timepoint. The fixed background is shared with the viewer.

Recipes record viewCapture, engine, layout, quality, camera and display settings. The Analysis integration's native 2D renderer cannot replay these screen-space recipes. Playback FPS is independent of acquisition timing.

Acceptance

The real Chrome smoke test covers four ordered frames at 5 FPS (0.8 seconds), seeking/replay, odd-size encoder padding, crop offsets, overlapping red/green labels, and mapped tracks with a missing observation. Frontend recipe tests cover bounded sequences and overlay validation. Live local OMERO checks also generated an annotated Image 66 movie through Analysis, saved the movie/poster/ recipe, and restored those artifacts from OMERO in fresh browser storage.

Run npm run smoke:movie from frontend with Chrome installed (or set CHROME_PATH). Screenshots, the MP4 and trace/report evidence are retained in frontend/test-results/; CI uploads that evidence. Current test and check results for this branch are available on its pull request.