Preview a vertical clip fast: video inspect seek fast, then cut exact

To skim a long vertical clip quickly, ask Sume video inspect for stills with frames.seek: "fast": each still comes from the keyframe at or before its time, so it can be earlier by up to one GOP (roughly 0 to 5 seconds on typical sources) but never later. Use the default precise seek only when a timestamp must be exact, such as before a trim.

The behavior is in the video inspect docs (read 2026-10-06). Sume says quality, resolution, and transcript do not change with fast; only the decode step is skipped.

What does the frames program allow?

The figures are laid out below.

How do I skim a 3-minute Short?

A 180-second clip with the default 8 stills gives one still every 22.5 seconds, mid-bin. For a closer look, send frames: {"fps": 0.1333, "seek": "fast"}, which yields about 24 stills across 180 seconds, or one every 7.5 seconds. Each still carries t, url, width, and height, and the grid reports sample_times (what the tiles show) next to requested_times.

When must I switch back to precise?

Before you cut. If you pick a start time from a fast still, the real frame may be up to a keyframe interval earlier, so use precise seek, or trim with precision: "exact" (the default in video trim) and read actual_start_seconds back from the result. A keyframe trim can start a GOP early too, so re-base your times against that field.