ffmpeg-video-editing

Cut, trim, concatenate, and split video files - basic video editing operations

Security Scan

This is an instruction-only FFmpeg helper whose commands and requirements match its stated purpose and do not request extra credentials, installs, or unrelated access.

Purpose & Capability

The name/description (cut, trim, concatenate, split videos) aligns with the provided content: concrete ffmpeg commands for cutting, concatenation, splitting, and re-encoding. Nothing requested is outside that scope.

Instruction Scope

SKILL.md contains only shell ffmpeg examples operating on local input/output files (e.g., input.mp4, list.txt). It does not instruct reading unrelated system files, environment variables, or sending data to external endpoints. The instructions are specific and scoped to video editing tasks.

Install Mechanism

No install spec and no code files — the skill is instruction-only. This minimizes risk because nothing is written to disk by the skill itself.

Credentials

No environment variables, credentials, or config paths are requested. The examples assume a local ffmpeg binary but do not demand any secrets or unrelated service access.

Persistence & Privilege

always is false and the skill does not request permanent presence or system configuration changes. It does not modify other skills or agent-wide settings.

Assessment

This skill is an offline cookbook of ffmpeg commands and is coherent with its description. Before using: ensure you have ffmpeg installed and are running commands in a safe working directory (backup originals first). If you allow an agent to run this autonomously, be aware it will execute shell commands that operate on whatever local file paths you give it — restrict file paths and review commands before execution. If you need automatic installs or integration with cloud storage, look for a skill that declares those requirements explicitly.

FFmpeg Video Editing Skill

Basic video editing operations: cutting, trimming, concatenating, and splitting videos.

When to Use

• Cut segments from video
• Trim video length
• Concatenate multiple videos
• Split video into parts
• Extract specific time ranges

Cutting and Trimming

# Cut from 10s to 30s (using -ss and -to)
ffmpeg -ss 00:00:10 -to 00:00:30 -i input.mp4 -c copy output.mp4

# Cut from 10s for 20 seconds duration
ffmpeg -ss 00:00:10 -t 20 -i input.mp4 -c copy output.mp4

# First 60 seconds
ffmpeg -t 60 -i input.mp4 -c copy output.mp4

# Last 30 seconds (need duration first)
ffmpeg -sseof -30 -i input.mp4 -c copy output.mp4

Precise Cutting

# With re-encoding (more precise)
ffmpeg -ss 00:00:10 -i input.mp4 -t 20 -c:v libx264 -c:a aac output.mp4

# Keyframe-accurate (faster, may be less precise)
ffmpeg -ss 00:00:10 -i input.mp4 -t 20 -c copy output.mp4

Concatenation

Method 1: File List (Recommended)

# Create list.txt file:
# file 'video1.mp4'
# file 'video2.mp4'
# file 'video3.mp4'

ffmpeg -f concat -safe 0 -i list.txt -c copy output.mp4

Method 2: Same Codec Files

# If all videos have same codec/format
ffmpeg -i "concat:video1.mp4|video2.mp4|video3.mp4" -c copy output.mp4

Method 3: Re-encode (Different Codecs)

# Re-encode for compatibility
ffmpeg -f concat -safe 0 -i list.txt -c:v libx264 -c:a aac output.mp4

Splitting Video

# Split into 60-second segments
ffmpeg -i input.mp4 -c copy -f segment -segment_time 60 \
  -reset_timestamps 1 output_%03d.mp4

# Split at specific timestamps
ffmpeg -i input.mp4 -ss 00:00:00 -t 00:01:00 -c copy part1.mp4
ffmpeg -i input.mp4 -ss 00:01:00 -t 00:01:00 -c copy part2.mp4

Extract Segment with Re-encoding

# When you need to change quality/codec
ffmpeg -ss 00:00:10 -i input.mp4 -t 20 \
  -c:v libx264 -crf 23 -c:a aac -b:a 192k output.mp4

Multiple Segments

# Extract multiple segments
ffmpeg -i input.mp4 \
  -ss 00:00:10 -t 00:00:05 -c copy segment1.mp4 \
  -ss 00:01:00 -t 00:00:10 -c copy segment2.mp4

Notes

• Use -c copy for speed (no re-encoding)
• -ss before -i is faster but less precise
• -ss after -i is more precise but slower
• Concatenation requires same codec/format for -c copy
• Use file list method for best concatenation results