Renders a node in isolation at one or more timeline positions and merges them into contact sheets: up to 12 positions per PNG, each cell labelled with the timecode of the frame actually rendered and drawn as large as the sheet allows, so a few positions arrive as one high-resolution picture instead of a directory to open one by one. --separate writes a PNG per position instead. The node is drawn offscreen, tightly framed to its own bounds; siblings and overlapping scene content are not included, so capture a scene id to check composition. To grab a video asset's own pixels instead of the composited node, use media grab.
<id>: node id to capture (required)-t, --time <time...>: one or more positions to capture, relative to the node's start (0= its first visible frame), each aTimevalue (optional; default0)-S, --separate: write one PNG per position instead of merging them into contact sheets (optional). Each is rendered at 720p height on a transparent background and named after its timecode (e.g.01s12f.png). The way to keep the alpha channel.--per-sheet <n>: positions per contact sheet, 1 to 12 (optional; default as many as fit). Fewer positions per sheet means a larger cell each. Sheets are balanced, so 13 positions become 7 + 6 rather than 12 + 1.-o, --output <dir>: directory to write the PNGs into (optional; default a freshdapi-capture-*directory in the system temp directory, so runs never overwrite each other). Writing into the same directory twice overwrites images whose name matches; with--separate, requested times that land on the same frame share one file.
Cell labels, the timecode field, and the filenames all use the same stamp, which drops its zero segments: 08s10f is 8 seconds and 10 frames, 01m05s is 65 seconds, and the node's first visible frame is 0f. Each segment carries its unit, so nothing is ambiguous once the empty ones are gone.
A sheet never exceeds 2576x1456, the largest image a vision model reads at full detail. Within that budget the grid is the one that draws each frame largest, and the last row may be partially filled. Cells render at their own size rather than the flat 720p of --separate, so a few positions are sharper than a standalone capture and never coarser; a node smaller than 1080p tall is rendered up to that height, and nothing is rendered beyond it. Sheets are named after the span they cover, e.g. 0f-11s.png. For a 16:9 scene the cell sizes are:
| Positions | Grid | Per-frame |
|---|---|---|
| 1 | 1x1 | 1920x1080 |
| 2-4 | 2x1, 2x2 | 1280x720 |
| 5-9 | 3x2, 3x3 | 850x478 |
| 10-12 | 4x3 | 636x357 |
Sheets are opaque: the node's transparent background composites onto flat grey, and the gutters between cells use the same grey. Use --separate when the alpha channel itself matters.
JSON Lines, one object per written image: a contact sheet by default, a position with --separate.
{ timecode: string; path: string } // e.g. { "timecode": "0f-01s15f", "path": "/tmp/dapi-capture-3f2c1a8e/0f-01s15f.png" }A sheet's timecode is the span it covers; a single position's is its own. Sheets come in timeline order, and their cells in the order the positions were requested in.
Exits non-zero if the id is unknown, the node has no timeline clock of its own (capture its scene instead), the node is not visible at any requested position, --per-sheet is outside 1 to 12, or a PNG can't be written.