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>
155 lines
3.5 KiB
Markdown
155 lines
3.5 KiB
Markdown
# FFmpeg Commands Reference
|
|
|
|
## Contents
|
|
|
|
- [Video Metadata Extraction](#video-metadata-extraction) - Getting video properties with ffprobe
|
|
- [Frame Extraction](#frame-extraction) - Extracting frames at intervals
|
|
- [Quality Metrics Calculation](#quality-metrics-calculation) - PSNR, SSIM, VMAF calculations
|
|
- [Video Information](#video-information) - Duration, resolution, frame rate, bitrate, codec queries
|
|
- [Image Processing](#image-processing) - Scaling and format conversion
|
|
- [Troubleshooting](#troubleshooting) - Debugging FFmpeg issues
|
|
- [Performance Optimization](#performance-optimization) - Speed and resource management
|
|
|
|
## Video Metadata Extraction
|
|
|
|
### Basic Video Info
|
|
```bash
|
|
ffprobe -v quiet -print_format json -show_format -show_streams input.mp4
|
|
```
|
|
|
|
### Stream-specific Information
|
|
```bash
|
|
ffprobe -v quiet -select_streams v:0 -print_format json -show_format -show_streams input.mp4
|
|
```
|
|
|
|
### Get Specific Fields
|
|
```bash
|
|
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
|
|
```bash
|
|
ffmpeg -i input.mp4 -vf "select='not(mod(t\,5))',setpts=N/FRAME_RATE/TB" -vsync 0 output_%03d.jpg
|
|
```
|
|
|
|
### Extract Every Nth Frame
|
|
```bash
|
|
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
|
|
```bash
|
|
ffmpeg -i input.mp4 -vf "fps=1/5,scale=-1:800" -q:v 2 frame_%05d.jpg
|
|
```
|
|
|
|
## Quality Metrics Calculation
|
|
|
|
### PSNR Calculation
|
|
```bash
|
|
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]psnr=stats_file=-" -f null -
|
|
```
|
|
|
|
### SSIM Calculation
|
|
```bash
|
|
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]ssim=stats_file=-" -f null -
|
|
```
|
|
|
|
### Combined PSNR and SSIM
|
|
```bash
|
|
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
|
|
```bash
|
|
ffmpeg -i original.mp4 -i compressed.mp4 -lavfi "[0:v][1:v]libvmaf=log_path=vmaf.log" -f null -
|
|
```
|
|
|
|
## Video Information
|
|
|
|
### Get Video Duration
|
|
```bash
|
|
ffprobe -v quiet -show_entries format=duration -of csv=p=0 input.mp4
|
|
```
|
|
|
|
### Get Video Resolution
|
|
```bash
|
|
ffprobe -v quiet -show_entries stream=width,height -of csv=p=0 input.mp4
|
|
```
|
|
|
|
### Get Frame Rate
|
|
```bash
|
|
ffprobe -v quiet -show_entries stream=r_frame_rate -of csv=p=0 input.mp4
|
|
```
|
|
|
|
### Get Bitrate
|
|
```bash
|
|
ffprobe -v quiet -show_entries format=bit_rate -of csv=p=0 input.mp4
|
|
```
|
|
|
|
### Get Codec Information
|
|
```bash
|
|
ffprobe -v quiet -show_entries stream=codec_name,codec_type -of csv=p=0 input.mp4
|
|
```
|
|
|
|
## Image Processing
|
|
|
|
### Scale to Fixed Height
|
|
```bash
|
|
ffmpeg -i input.jpg -vf "scale=-1:800" output.jpg
|
|
```
|
|
|
|
### Scale to Fixed Width
|
|
```bash
|
|
ffmpeg -i input.jpg -vf "scale=1200:-1" output.jpg
|
|
```
|
|
|
|
### High Quality JPEG
|
|
```bash
|
|
ffmpeg -i input.jpg -q:v 2 output.jpg
|
|
```
|
|
|
|
### Progressive JPEG
|
|
```bash
|
|
ffmpeg -i input.jpg -q:v 2 -progressive output.jpg
|
|
```
|
|
|
|
## Troubleshooting
|
|
|
|
### Check FFmpeg Version
|
|
```bash
|
|
ffmpeg -version
|
|
```
|
|
|
|
### Check Available Filters
|
|
```bash
|
|
ffmpeg -filters
|
|
```
|
|
|
|
### Test Video Decoding
|
|
```bash
|
|
ffmpeg -i input.mp4 -f null -
|
|
```
|
|
|
|
### Extract First Frame
|
|
```bash
|
|
ffmpeg -i input.mp4 -vframes 1 -q:v 2 first_frame.jpg
|
|
```
|
|
|
|
## Performance Optimization
|
|
|
|
### Use Multiple Threads
|
|
```bash
|
|
ffmpeg -threads 4 -i input.mp4 -c:v libx264 -preset fast output.mp4
|
|
```
|
|
|
|
### Set Timeout
|
|
```bash
|
|
timeout 300 ffmpeg -i input.mp4 -c:v libx264 output.mp4
|
|
```
|
|
|
|
### Limit Memory Usage
|
|
```bash
|
|
ffmpeg -i input.mp4 -c:v libx264 -x264-params threads=2:ref=3 output.mp4
|
|
``` |