9b724f33e3
## New Skill: video-comparer v1.0.0 - Compare original and compressed videos with interactive HTML reports - Calculate quality metrics (PSNR, SSIM) for compression analysis - Generate frame-by-frame visual comparisons (slider, side-by-side, grid) - Extract video metadata (codec, resolution, bitrate, duration) - Multi-platform FFmpeg support with security features ## transcript-fixer Enhancements - Add async AI processor for parallel processing - Add connection pool management for database operations - Add concurrency manager and rate limiter - Add audit log retention and database migrations - Add health check and metrics monitoring - Add comprehensive test suite (8 new test files) - Enhance security with domain and path validators ## Marketplace Updates - Update marketplace version from 1.8.0 to 1.9.0 - Update skills count from 15 to 16 - Update documentation (README.md, CLAUDE.md, CHANGELOG.md) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
3.5 KiB
3.5 KiB
FFmpeg Commands Reference
Contents
- Video Metadata Extraction - Getting video properties with ffprobe
- Frame Extraction - Extracting frames at intervals
- Quality Metrics Calculation - PSNR, SSIM, VMAF calculations
- Video Information - Duration, resolution, frame rate, bitrate, codec queries
- Image Processing - Scaling and format conversion
- Troubleshooting - Debugging FFmpeg issues
- Performance Optimization - Speed and resource management
Video Metadata Extraction
Basic Video Info
ffprobe -v quiet -print_format json -show_format -show_streams input.mp4
Stream-specific Information
ffprobe -v quiet -select_streams v:0 -print_format json -show_format -show_streams input.mp4
Get Specific Fields
ffprobe -v quiet -show_entries format=duration -show_entries stream=width,height,codec_name,r_frame_rate -of csv=p=0 input.mp4
Frame Extraction
Extract Frames at Intervals
ffmpeg -i input.mp4 -vf "select='not(mod(t\,5))',setpts=N/FRAME_RATE/TB" -vsync 0 output_%03d.jpg
Extract Every Nth Frame
ffmpeg -i input.mp4 -vf "select='not(mod(n\,150))',scale=-1:800" -vsync 0 -q:v 2 frame_%03d.jpg
Extract Frames with Timestamp
ffmpeg -i input.mp4 -vf "fps=1/5,scale=-1:800" -q:v 2 frame_%05d.jpg
Quality Metrics Calculation
PSNR Calculation
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]psnr=stats_file=-" -f null -
SSIM Calculation
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]ssim=stats_file=-" -f null -
Combined PSNR and SSIM
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi '[0:v][1:v]psnr=stats_file=-;[0:v][1:v]ssim=stats_file=-' -f null -
VMAF Calculation
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]libvmaf=log_path=vmaf.log" -f null -
Video Information
Get Video Duration
ffprobe -v quiet -show_entries format=duration -of csv=p=0 input.mp4
Get Video Resolution
ffprobe -v quiet -show_entries stream=width,height -of csv=p=0 input.mp4
Get Frame Rate
ffprobe -v quiet -show_entries stream=r_frame_rate -of csv=p=0 input.mp4
Get Bitrate
ffprobe -v quiet -show_entries format=bit_rate -of csv=p=0 input.mp4
Get Codec Information
ffprobe -v quiet -show_entries stream=codec_name,codec_type -of csv=p=0 input.mp4
Image Processing
Scale to Fixed Height
ffmpeg -i input.jpg -vf "scale=-1:800" output.jpg
Scale to Fixed Width
ffmpeg -i input.jpg -vf "scale=1200:-1" output.jpg
High Quality JPEG
ffmpeg -i input.jpg -q:v 2 output.jpg
Progressive JPEG
ffmpeg -i input.jpg -q:v 2 -progressive output.jpg
Troubleshooting
Check FFmpeg Version
ffmpeg -version
Check Available Filters
ffmpeg -filters
Test Video Decoding
ffmpeg -i input.mp4 -f null -
Extract First Frame
ffmpeg -i input.mp4 -vframes 1 -q:v 2 first_frame.jpg
Performance Optimization
Use Multiple Threads
ffmpeg -threads 4 -i input.mp4 -c:v libx264 -preset fast output.mp4
Set Timeout
timeout 300 ffmpeg -i input.mp4 -c:v libx264 output.mp4
Limit Memory Usage
ffmpeg -i input.mp4 -c:v libx264 -x264-params threads=2:ref=3 output.mp4