OpenParable
Skip to content
← Back to skills

Contact Sheet

Documents
contact-sheet

Contact Sheet is an Agent Skill for documents published in the barefootford/buttercut repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Builds a contact sheet from a video clip — evenly spaced frames laid out in a single grid image, each with its hh:mm:ss timestamp burned in. Use when the user asks for a "contact sheet", "grid", "film strip", or wants a one-image overview of part of a clip.

View on GitHub ↗
QUICK START

How to use this skill

Bring this guide into your coding agent with a prompt tailored to the tool you use.

  1. Open your project in Codex.
  2. Copy and paste the prompt below.
  3. Review files and risks before approving any action.
Prompt to paste
Inspect the Agent Skill at https://github.com/barefootford/buttercut/blob/HEAD/skills/contact-sheet/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/contact-sheet, but wait for my approval before writing files or running scripts.

Copying this prompt does not install or run the skill. Review third-party files before use.

Skill: Contact Sheet

Builds a contact sheet from a slice of a video clip: 16 evenly spaced frames laid out in a 4x4 grid, each annotated with its hh:mm:ss timestamp.

Prerequisite: ffmpeg with drawtext

This skill burns timestamps onto frames with ffmpeg's drawtext filter. ButterCut resolves ffmpeg from the repo's dependencies/ directory first, then PATH, and raises a clear error when it's in neither place. If a run fails with that missing-ffmpeg error, or with No such filter: 'drawtext' (some PATH builds, notably the stock Homebrew formula, omit drawtext), run the setup skill to install a suitable ffmpeg, then retry the contact sheet.

Run

When the clip belongs to a library, always pass --library so the output lands in the standard place:

# Whole clip
ruby lib/buttercut/contact_sheet.rb <video-path> --library libraries/<lib>

# From <start> to the end of the clip
ruby lib/buttercut/contact_sheet.rb <video-path> <start> --library libraries/<lib>

# Explicit range
ruby lib/buttercut/contact_sheet.rb <video-path> <start> <end> --library libraries/<lib>

<start> and <end> accept seconds (e.g. 12.5) or HH:MM:SS / MM:SS.

Options: --library DIR, --output PATH (exact path; overrides --library).

Frame count is chosen automatically: 16 frames in a 4x4 grid for clips longer than 10 seconds, 4 frames in a 2x2 grid for clips of 10 seconds or less (avoids duplicates).

Portrait clips (iPhone, etc.) are auto-rotated using the source's container rotation metadata so timestamps land right-side-up. Variable-frame-rate sources (screen recordings, some action cams) are detected and routed through the slower seek-and-grab path automatically.

Output location

  • With --library DIR: saved to <library>/contact_sheets/<clipname>_<descriptor>.jpg.
    • <descriptor> is full when covering the whole clip, otherwise HH-MM-SS_to_HH-MM-SS (dashes instead of colons).
    • Examples: contact_sheets/DJI_20251126164651_0278_D_full.jpg, contact_sheets/DJI_20251126164651_0278_D_00-00-30_to_00-01-00.jpg.
    • The contact_sheets/ directory is created automatically if missing.
  • Without --library (and no --output): saved next to the source video with the same _<descriptor> suffix. Fine for quick one-off testing, but library work should always pass --library.

After running

Share the output path as a clickable link so the user can open it directly.