AgentSkillsCN

video-trimmer

按时间戳精准修剪与切割视频。支持流式复制（速度快）与重新编码（画质优）两种模式。当您需要从视频中提取特定片段、从精彩内容中制作短视频，或剪除不必要部分时，可选用此功能。

SKILL.md
--- frontmatter
name: video-trimmer
description: Trim and cut videos by timestamp with precision. Supports both stream copy (fast) and re-encoding (quality) modes. Use when you need to extract specific segments from videos, create clips from highlights, or cut unwanted portions.
allowed-tools: Bash(ffmpeg:*)
compatibility: Requires FFmpeg
metadata:
  version: "1.0"

Video Trimmer

This skill enables AI agents to trim and cut videos with precision using FFmpeg.

When to Use

  • •User wants to extract a specific segment from a video
  • •Creating clips from highlight timestamps
  • •Removing unwanted portions from videos
  • •Cutting videos for short-form content
  • •Trimming based on detected highlights

Available Scripts

scripts/trim.py

Trim video to specified time range.

Usage:

bash
python skills/video-trimmer/scripts/trim.py <video_path> [options]

Options:

  • •--start, -s: Start time (seconds or HH:MM:SS) - required
  • •--end, -e: End time (seconds or HH:MM:SS) - required
  • •--output, -o: Output video path (default: <video_path>_trimmed.mp4)
  • •--reencode: Re-encode video (higher quality, slower)
  • •--codec: Video codec for re-encoding (default: libx264)
  • •--quality: Quality preset (fast, medium, slow) - default: fast
  • •--copy: Use stream copy (faster, no quality loss)

Examples:

Trim 10-second segment:

bash
python skills/video-trimmer/scripts/trim.py video.mp4 --start 30 --end 40

Trim with timestamp format:

bash
python skills/video-trimmer/scripts/trim.py video.mp4 --start 00:01:30 --end 00:01:45

Re-encode for better quality:

bash
python skills/video-trimmer/scripts/trim.py video.mp4 --start 30 --end 40 --reencode --quality medium

Fast stream copy:

bash
python skills/video-trimmer/scripts/trim.py video.mp4 --start 30 --end 40 --copy

scripts/trim_multiple.py

Trim multiple segments from one video.

Usage:

bash
python skills/video-trimmer/scripts/trim_multiple.py <video_path> --segments <json_file> [options]

Options:

  • •--segments: JSON file with segment list
  • •--output-dir: Output directory (default: ./clips/)
  • •--copy: Use stream copy
  • •--prefix: Filename prefix for clips

Segments JSON Format:

json
[
  {"start": 30, "end": 45},
  {"start": 120, "end": 135},
  {"start": 200, "end": 220}
]

Example:

bash
python skills/video-trimmer/scripts/trim_multiple.py video.mp4 --segments segments.json --prefix highlight

Output

Single Trim

Returns trimmed video file:

code
video_trimmed.mp4

Multiple Trims

Returns multiple clip files:

code
clips/
  highlight_001.mp4
  highlight_002.mp4
  highlight_003.mp4

Modes Explained

Stream Copy (Default, Fast)

  • •Speed: Very fast (seconds)
  • •Quality: No quality loss (exact copy)
  • •Use when: Quick cuts, same codec segments
  • •Limitations: Cut points may not be frame-perfect

Re-encode (High Quality)

  • •Speed: Slower (depends on length)
  • •Quality: Frame-perfect, configurable quality
  • •Use when: Frame-accurate cuts, codec conversion
  • •Options: Adjust CRF for quality vs file size

Time Formats

Supported time formats:

  • •Seconds: 30, 45.5, 120
  • •MM:SS: 1:30, 2:45
  • •HH:MM:SS: 00:01:30, 01:15:30

Integration with Other Skills

After trimming, you can use these skills:

  • •portrait-resizer: Convert to 9:16 portrait format
  • •subtitle-overlay: Add captions to clips
  • •autocut-shorts: Full workflow with all steps

Common Workflow

  1. •User provides video file
  2. •Find highlights using highlight-scanner
  3. •Trim segments using this skill
  4. •Resize to portrait using portrait-resizer
  5. •Add subtitles using subtitle-overlay

Tips

  • •Use --copy for fast processing when quality isn't critical
  • •Use --reencode for frame-perfect cuts
  • •Trimming before resizing is more efficient
  • •Keep 2-3 second buffers around highlights for context
  • •Use JSON input for batch trimming

Error Handling

  • •Invalid timestamps: Returns error with valid range
  • •Out of bounds: Clamps to video duration
  • •File not found: Clear error message
  • •Codec issues: Falls back to re-encoding

Performance

  • •Stream copy: ~1 second per minute of video
  • •Re-encode: ~5-30 seconds per minute (depends on quality)
  • •Batch processing: Processes sequentially

References