agent-bank: Skill for OpenCode

.opencode/skill/video-subtitle-cutter/SKILL.md

video-subtitle-cutter is a skill for OpenCode from different-ai/agent-bank. It costs 27 tokens per session (4,588 once invoked), scanned B, original, MIT.

A video-editing workflow that turns speech into timestamped subtitles, uses AI to identify unwanted parts, and creates a shorter video. It can target filler words, pauses, and mistakes, then produce subtitles for the result.

In plain words
What is it for?
Transcribing videos, finding filler words and mistakes, cutting and joining clean sections with FFmpeg, and creating SRT subtitle files.
Why use it?
It reduces the manual work of finding and cutting unwanted speech. Re-encoding the video helps avoid frozen frames and audio or video sync problems at cut points.

Skill for OpenCode

Written for OpenCode: installed under .opencode/. Also seen: mentions OpenCode.

This is different-ai/agent-bank's own configuration. It tells OpenCode how to work on agent-bank itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything agent-bank configures →

Reuse

Borrowing it

Nothing to install: this file belongs to different-ai/agent-bank. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/different-ai/agent-bank/main/.opencode/skill/video-subtitle-cutter/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/different-ai/agent-bank

Made for: OpenCode.

Wrote this? Show the measurements

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agentmods badge for video-subtitle-cutter

README.md
[![agentmods](https://agentmods.dev/badge/skills/different-ai/agent-bank/video-subtitle-cutter/github.svg)](https://agentmods.dev/skills/different-ai/agent-bank/video-subtitle-cutter)
Your own site
<a href="https://agentmods.dev/skills/different-ai/agent-bank/video-subtitle-cutter"><img src="https://agentmods.dev/badge/skills/different-ai/agent-bank/video-subtitle-cutter/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/different-ai/agent-bank/video-subtitle-cutter"><img src="https://agentmods.dev/badge/skills/different-ai/agent-bank/video-subtitle-cutter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,588 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 3 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00027 $0.04588
Opus 5 $0.00014 $0.02294
Sonnet 5 $0.00005 $0.00918
Haiku 4.5 $0.00003 $0.00459

Measured 11d ago against content hash 5da7df0f1f73, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

video-subtitle-cutter scanned grade B with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo apt install ffmpeg # Linux

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl https://api.openai.com/v1/audio/transcriptions \

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

subprocess.run(cmd, capture_output=True)
.opencode/skill/video-subtitle-cutter/SKILL.md · 623 lines

How it starts

The opening of the file, as written. The whole thing — 623 lines — stays where its author put it; the contents beside it link to each section on GitHub.

What I Do

Automate video editing by:

  1. Transcribing video to timestamped subtitles (Whisper)
  2. Analyzing transcript with AI to identify cuts (filler words, pauses, mistakes)
  3. Generating FFmpeg commands to cut and concatenate clean segments
  4. Generating subtitles (SRT) for the final video

CRITICAL: Always Re-encode (Never Use -c copy)

The #1 mistake is using -c copy for cutting. This causes:

  • Frozen frames at cut points (1-8 seconds of freeze)
  • Audio/video sync issues
  • Glitchy playback

Why? H.264 video uses keyframes (I-frames) every 2-10 seconds. -c copy can only cut at keyframes, so FFmpeg includes extra frames that display as frozen.

Solution: Always re-encode segments with quality settings:

# WRONG - causes freeze frames
ffmpeg -ss 10 -i video.mp4 -t 5 -c copy segment.mp4

# CORRECT - smooth cuts at any timestamp
ffmpeg -ss 10 -i video.mp4 -t 5 \
  -c:v libx264 -preset fast -crf 18 \
  -c:a aac -b:a 192k \
  -avoid_negative_ts make_zero \
  segment.mp4

Quality presets (CRF = Constant Rate Factor):

  • crf 15-17 = Near lossless (large files)
  • crf 18-20 = High quality (recommended)
  • crf 21-23 = Good quality (smaller files)
  • crf 24-28 = Medium quality (much smaller)

Prerequisites

# Install Whisper (choose one)
pip install openai-whisper          # Local (requires Python 3.9+)
# OR use OpenAI API (no local install needed)

# Install FFmpeg
brew install ffmpeg                  # macOS
sudo apt install ffmpeg              # Linux

Quick Start

Step 1: Transcribe Video

Option A: Local Whisper (free, slower)

whisper video.mp4 --model medium --output_format json --output_dir ./

Option B: OpenAI Whisper API (fast, paid)

curl https://api.openai.com/v1/audio/transcriptions \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -F file="@video.mp4" \
  -F model="whisper-1" \
  -F response_format="verbose_json" \
  -F timestamp_granularities[]="segment" \
  > transcript.json

Read the full file on GitHub · 623 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 623 lines · 27 tokens per session scan B 5da7df0f1f73

Subscribe to this mod's changes

video-subtitle-cutter is a skill published in the GitHub repository different-ai/agent-bank (249 stars, last pushed 5mo ago), licensed MIT. It adds 27 tokens to every session and 4,588 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 3 findings (asks for root, makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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