video-comparer
- Repo stars 1,187
- Forks 185
- Author updated Jun 14, 2026, 10:01 AM
- Author repo claude-code-skills
- Domain
- Other
- Compatible agents
-
- Claude Code
- Cursor
- Cline
- Codex
- Windsurf
- Gemini CLI
- +20
- Trust score
- 88 / 100 · community maintained
- Author / version / license
- @daymade · no license declared
- Token usage
- Lean
- Setup complexity
- Guided setup
- External API key
- Not required
- Operating systems
- macOS · Linux · Windows
- Runtime requirements
- Python >=3.8
- Permissions
-
- Read-only
- Write / modify
- Shell exec
- Network behavior
- Local-only
- Install commands
- 26 variants
Profile is derived at build time from SKILL.md and install vectors. Subject to drift from author intent.
Heads up: 未限定 allowed-tools,默认拥有全部工具权限。
---
name: video-comparer
description: This skill should be used when comparing two videos to analyze compression results or quality di…
category: other
runtime: Python
---
# video-comparer output preview
## PART A: Task fit
- Use case: This skill should be used when comparing two videos to analyze compression results or quality differences. Generates interactive HTML reports with quality metrics (PSNR, SSIM) and frame-by-frame visual comparisons. Triggers when users mention "compare videos", "video quality", "compression analysis", "before/after compression", or request quality assessment of compressed videos..
- Inputs: target material, constraints, expected output, and acceptance criteria.
- Evidence boundary: follow “Overview / When to Use This Skill / Core Usage” and do not present inference as author intent.
## PART B: Execution result
- **01** The card summarizes the use case; runtime output centers on “This skill should be used when comparing two videos to analyze compression results or quality differences. Generates interactive HTML reports with quality metrics (PSNR, SSIM) and frame-by-frame visual comparisons. Triggers when users mention "compare videos", "video quality", "compression analysis", "before/after compression", or request quality assessment of compressed videos.”.
- **02** When the source has headings, the agent prioritizes “Overview / When to Use This Skill / Core Usage” so the result follows the author’s structure.
- **03** Typical output includes task judgment, concrete steps, required commands or file edits, validation, and follow-up options.
- **04** Risk context follows the fingerprint: read files, write/modify files, run shell commands; mostly runs locally; usually needs no extra API key.
## Running Rules
- read files, write/modify files, run shell commands; mostly runs locally; usually needs no extra API key.
- Validate with a small sample before expanding scope.
- Return the result, validation criteria, and next iteration options. The source does not require a stable slash command. After installation, invoke the skill by name and describe the task.
Name target files or source material, expected output, forbidden changes, and whether network or shell access is allowed. Permission fingerprint: read files, write/modify files, run shell commands.
Start with a small task and check whether the result follows “Overview / When to Use This Skill / Core Usage”. Inspect diffs, logs, previews, or tests before expanding scope.
Confirm the final output includes a concrete result, evidence, and next action. If it stays generic, tighten inputs, boundaries, and acceptance criteria.
---
name: video-comparer
description: This skill should be used when comparing two videos to analyze compression results or quality di…
category: other
source: daymade/claude-code-skills
---
# video-comparer
## When to use
- This skill should be used when comparing two videos to analyze compression results or quality differences. Generates i…
- Use it when the task has clear inputs, repeatable steps, and validation criteria.
## What to provide
- Target material, scope, expected result, and forbidden changes.
- Whether network, commands, file writes, or external services are allowed.
## Execution rules
- Organize steps around “Overview / When to Use This Skill / Core Usage” and keep inference separate from source facts.
- read files, write/modify files, run shell commands; mostly runs locally; usually needs no extra API key.
- Validate with a small sample before expanding the task.
## Output requirements
- Return the deliverable, key evidence, validation method, and next action.
- Mark missing information as unknown; do not invent commands, platforms, or dependencies. The author source anchors workflow facts; repository files anchor sources and commands; Fluxly only adds fit, limitations, and quality judgment.
skill "video-comparer" {
input -> user goal + target files + boundaries + acceptance criteria
context -> Overview / When to Use This Skill / Core Usage
rules -> SKILL.md triggers / order / output contract
runtime -> Python | read files, write/modify files, run shell commands | mostly runs locally
guardrails -> usually needs no extra API key + small-sample validation + diff/log review
output -> copyable result + checklist + next iteration
} Video Comparer
Overview
Compare two videos and generate an interactive HTML report analyzing compression results. The script extracts video metadata, calculates quality metrics (PSNR, SSIM), and creates frame-by-frame visual comparisons with three viewing modes: slider, side-by-side, and grid.
When to Use This Skill
Use this skill when:
- Comparing original and compressed videos
- Analyzing video compression quality and efficiency
- Evaluating codec performance or bitrate reduction impact
- Users mention "compare videos", "video quality", "compression analysis", or "before/after compression"
Core Usage
Basic Command
python3 scripts/compare.py original.mp4 compressed.mp4
Generates comparison.html with:
- Video parameters (codec, resolution, bitrate, duration, file size)
- Quality metrics (PSNR, SSIM, size/bitrate reduction percentages)
- Frame-by-frame comparison (default: frames at 5s intervals)
Command Options
# Custom output file
python3 scripts/compare.py original.mp4 compressed.mp4 -o report.html
# Custom frame interval (larger = fewer frames, faster processing)
python3 scripts/compare.py original.mp4 compressed.mp4 --interval 10
# Batch comparison
for original in originals/*.mp4; do
compressed="compressed/$(basename "$original")"
output="reports/$(basename "$original" .mp4).html"
python3 scripts/compare.py "$original" "$compressed" -o "$output"
done
Requirements
System Dependencies
FFmpeg and FFprobe (required for video analysis and frame extraction):
# macOS
brew install ffmpeg
# Ubuntu/Debian
sudo apt update && sudo apt install ffmpeg
# Windows
# Download from https://ffmpeg.org/download.html
# Or use: winget install ffmpeg
Python 3.8+ (uses type hints, f-strings, pathlib)
Video Specifications
- Supported formats:
.mp4(recommended),.mov,.avi,.mkv,.webm - File size limit: 500MB per video (configurable)
- Processing time: ~1-2 minutes for typical videos; varies by duration and frame interval
Script Behavior
Automatic Validation
The script automatically validates:
- FFmpeg/FFprobe installation and availability
- File existence, extensions, and size limits
- Path security (prevents directory traversal)
Clear error messages with resolution guidance appear when validation fails.
Quality Metrics
The script calculates two standard quality metrics:
PSNR (Peak Signal-to-Noise Ratio): Pixel-level similarity measurement (20-50 dB scale, higher is better)
SSIM (Structural Similarity Index): Perceptual similarity measurement (0.0-1.0 scale, higher is better)
For detailed interpretation scales and quality thresholds, consult references/video_metrics.md.
Frame Extraction
The script extracts frames at specified intervals (default: 5 seconds), scales them to consistent height (800px) for comparison, and embeds them as base64 data URLs in self-contained HTML. Temporary files are automatically cleaned after processing.
Output Report
The generated HTML report includes:
- Slider Mode: Drag to reveal original vs compressed (default)
- Side-by-Side Mode: Simultaneous display for direct comparison
- Grid Mode: Compact 2-column layout
- Zoom Controls: 50%-200% magnification
- Self-contained format (no server required, works offline)
Important Implementation Details
Security
The script implements:
- Path validation (absolute paths, prevents directory traversal)
- Command injection prevention (no
shell=True, validated arguments) - Resource limits (file size, timeouts)
- Custom exceptions:
ValidationError,FFmpegError,VideoComparisonError
Common Error Scenarios
"FFmpeg not found": Install FFmpeg via platform package manager (see Requirements section)
"File too large": Compress videos before comparison, or adjust MAX_FILE_SIZE_MB in scripts/compare.py
"Operation timed out": Increase FFMPEG_TIMEOUT constant or use larger --interval value (processes fewer frames)
"Frame count mismatch": Videos have different durations/frame rates; script auto-truncates to minimum frame count and shows warning
Configuration
The script includes adjustable constants for file size limits, timeouts, frame dimensions, and extraction intervals. To customize behavior, edit the constants at the top of scripts/compare.py. For detailed configuration options and their impacts, consult references/configuration.md.
Reference Materials
Consult these files for detailed information:
references/video_metrics.md: Quality metrics interpretation (PSNR/SSIM scales, compression targets, bitrate guidelines)references/ffmpeg_commands.md: FFmpeg command reference (metadata extraction, frame extraction, troubleshooting)references/configuration.md: Script configuration options and adjustable constantsassets/template.html: HTML report template for customizing viewing modes and styling
Decide Fit First
Design Intent
How To Use It
Boundaries And Review