Media Processing

Codex compatibility note:

>

- Invoke repository skills with $skill-name in Codex; this mirrored copy rewrites legacy Claude /skill-name references.

- Task tracker mandate: BEFORE executing any workflow or skill step, create/update task tracking for all steps and keep it synchronized as progress changes.

- User-question prompts mean to ask the user directly in Codex.

- Ignore Claude-specific mode-switch instructions when they appear.

- Strict execution contract: when a user explicitly invokes a skill, execute that skill protocol as written.

- Subagent authorization: when a skill is user-invoked or AI-detected and its protocol requires subagents, that skill activation authorizes use of the required spawn_agent subagent(s) for that task.

- Do not skip, reorder, or merge protocol steps unless the user explicitly approves the deviation first.

- For workflow skills, execute each listed child-skill step explicitly and report step-by-step evidence.

- If a required step/tool cannot run in this environment, stop and ask the user before adapting.

<!-- CODEX:PROJECT-REFERENCE-LOADING:START -->

Codex Project-Reference Loading (No Hooks)

Codex does not receive Claude hook-based doc injection. When coding, planning, debugging, testing, or reviewing, open project docs explicitly using this routing.

Always read:

• docs/project-config.json (project-specific paths, commands, modules, and workflow/test settings)
• docs/project-reference/docs-index-reference.md (routes to the full docs/project-reference/* catalog)
• docs/project-reference/lessons.md (always-on guardrails and anti-patterns)

Situation-based docs:

• Backend/CQRS/API/domain/entity changes: backend-patterns-reference.md, domain-entities-reference.md, project-structure-reference.md
• Frontend/UI/styling/design-system: frontend-patterns-reference.md, scss-styling-guide.md, design-system/README.md
• Spec/test-case planning or TC mapping: feature-docs-reference.md
• Integration test implementation/review: integration-test-reference.md
• E2E test implementation/review: e2e-test-reference.md
• Code review/audit work: code-review-rules.md plus domain docs above based on changed files

Do not read all docs blindly. Start from docs-index-reference.md, then open only relevant files for the task.

<!-- CODEX:PROJECT-REFERENCE-LOADING:END -->

Quick Summary

Goal: Process multimedia files using FFmpeg for video/audio encoding, conversion, streaming, and filtering.

Workflow:

1. Identify -- Match input to correct FFmpeg operation (convert, trim, merge, compress) 2. Execute -- Run FFmpeg command with appropriate codec and quality settings 3. Verify -- Check output file integrity and quality

Key Rules:

• Use tool selection table to pick correct FFmpeg operation
• Prefer hardware-accelerated encoding when available
• Always verify output file exists and is playable

Be skeptical. Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence percentages (Idea should be more than 80%).

Media Processing Skill

Process video, audio, and images using FFmpeg, ImageMagick, and RMBG CLI tools.

Tool Selection

Installation

# macOS
brew install ffmpeg imagemagick
npm install -g rmbg-cli

# Ubuntu/Debian
sudo apt-get install ffmpeg imagemagick
npm install -g rmbg-cli

# Verify
ffmpeg -version && magick -version && rmbg --version

Essential Commands

# Video: Convert/re-encode
ffmpeg -i input.mkv -c copy output.mp4
ffmpeg -i input.avi -c:v libx264 -crf 22 -c:a aac output.mp4

# Video: Extract audio
ffmpeg -i video.mp4 -vn -c:a copy audio.m4a

# Image: Convert/resize
magick input.png output.jpg
magick input.jpg -resize 800x600 output.jpg

# Image: Batch resize
mogrify -resize 800x -quality 85 *.jpg

# Background removal
rmbg input.jpg                          # Basic (modnet)
rmbg input.jpg -m briaai -o output.png  # High quality
rmbg input.jpg -m u2netp -o output.png  # Fast

Key Parameters

FFmpeg:

• -c:v libx264 - H.264 codec
• -crf 22 - Quality (0-51, lower=better)
• -preset slow - Speed/compression balance
• -c:a aac - Audio codec

ImageMagick:

• 800x600 - Fit within (maintains aspect)
• 800x600^ - Fill (may crop)
• -quality 85 - JPEG quality
• -strip - Remove metadata

RMBG:

• -m briaai - High quality model
• -m u2netp - Fast model
• -r 4096 - Max resolution

References

Detailed guides in references/:

• ffmpeg-encoding.md - Codecs, quality, hardware acceleration
• ffmpeg-streaming.md - HLS/DASH, live streaming
• ffmpeg-filters.md - Filters, complex filtergraphs
• imagemagick-editing.md - Effects, transformations
• imagemagick-batch.md - Batch processing, parallel ops
• rmbg-background-removal.md - AI models, CLI usage
• common-workflows.md - Video optimization, responsive images, GIF creation
• troubleshooting.md - Error fixes, performance tips
• format-compatibility.md - Format support, codec recommendations

---

[IMPORTANT] Use task tracking to break ALL work into small tasks BEFORE starting — including tasks for each file read. This prevents context loss from long files. For simple tasks, AI MUST ATTENTION ask user whether to skip.

<!-- SYNC:ai-mistake-prevention -->

AI Mistake Prevention — Failure modes to avoid on every task:

>

Check downstream references before deleting. Deleting components causes documentation and code staleness cascades. Map all referencing files before removal.

Verify AI-generated content against actual code. AI hallucinates APIs, class names, and method signatures. Always grep to confirm existence before documenting or referencing.

Trace full dependency chain after edits. Changing a definition misses downstream variables and consumers derived from it. Always trace the full chain.

Trace ALL code paths when verifying correctness. Confirming code exists is not confirming it executes. Always trace early exits, error branches, and conditional skips — not just happy path.

When debugging, ask "whose responsibility?" before fixing. Trace whether bug is in caller (wrong data) or callee (wrong handling). Fix at responsible layer — never patch symptom site.

Assume existing values are intentional — ask WHY before changing. Before changing any constant, limit, flag, or pattern: read comments, check git blame, examine surrounding code.

Verify ALL affected outputs, not just the first. Changes touching multiple stacks require verifying EVERY output. One green check is not all green checks.

Holistic-first debugging — resist nearest-attention trap. When investigating any failure, list EVERY precondition first (config, env vars, DB names, endpoints, DI registrations, data preconditions), then verify each against evidence before forming any code-layer hypothesis.

Surgical changes — apply the diff test. Bug fix: every changed line must trace directly to the bug. Don't restyle or improve adjacent code. Enhancement task: implement improvements AND announce them explicitly.

Surface ambiguity before coding — don't pick silently. If request has multiple interpretations, present each with effort estimate and ask. Never assume all-records, file-based, or more complex path.

<!-- /SYNC:ai-mistake-prevention -->

<!-- SYNC:critical-thinking-mindset -->

Critical Thinking Mindset — Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act.

Anti-hallucination: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination.

<!-- /SYNC:critical-thinking-mindset -->

<!-- SYNC:critical-thinking-mindset:reminder -->

MUST ATTENTION apply critical thinking — every claim needs traced proof, confidence >80% to act. Anti-hallucination: never present guess as fact.

<!-- /SYNC:critical-thinking-mindset:reminder -->

<!-- SYNC:ai-mistake-prevention:reminder -->

MUST ATTENTION apply AI mistake prevention — holistic-first debugging, fix at responsible layer, surface ambiguity before coding, re-read files after compaction.

<!-- /SYNC:ai-mistake-prevention:reminder -->

Closing Reminders

• MANDATORY IMPORTANT MUST ATTENTION break work into small todo tasks using task tracking BEFORE starting
• MANDATORY IMPORTANT MUST ATTENTION search codebase for 3+ similar patterns before creating new code
• MANDATORY IMPORTANT MUST ATTENTION cite file:line evidence for every claim (confidence >80% to act)
• MANDATORY IMPORTANT MUST ATTENTION add a final review todo task to verify work quality

[TASK-PLANNING] Before acting, analyze task scope and systematically break it into small todo tasks and sub-tasks using task tracking.

<!-- CODEX:SYNC-PROMPT-PROTOCOLS:START -->

Hookless Prompt Protocol Mirror (Auto-Synced)

Source: .claude/hooks/lib/prompt-injections.cjs + .claude/.ck.json

[WORKFLOW-EXECUTION-PROTOCOL] [BLOCKING] Workflow Execution Protocol — MANDATORY IMPORTANT MUST CRITICAL. Do not skip for any reason.

Generic portability boundary: Reusable skills and protocol text stay project-neutral; project-specific conventions are discovered from docs/project-config.json and docs/project-reference/. Apply shared AI-SDD from shared/sdd-artifact-contract.md. Read docs/project-config.json and docs/project-reference/docs-index-reference.md, then open the project reference docs named there. Any supported AI tool may execute when this shared context and local docs are available.

1. DETECT: Match prompt against workflow catalog 2. ANALYZE: Find best-match workflow AND evaluate if a custom step combination would fit better 3. ASK (REQUIRED FORMAT): Use a direct user question with this structure unless the user explicitly invoked a workflow/skill and the local protocol treats explicit invocation as confirmation:

• Question: "Which workflow do you want to activate?"
• Option 1: "Activate [BestMatch Workflow] (Recommended)"
• Option 2: "Activate custom workflow: [step1 → step2 → ...]" (include one-line rationale)

4. ACTIVATE (if confirmed): Call $workflow-start <workflowId> for standard; sequence custom steps manually 5. CREATE TASKS: task tracking for ALL workflow steps 6. EXECUTE: Follow each step in sequence [CRITICAL-THINKING-MINDSET] Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act. Anti-hallucination principle: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination. AI Attention principle (Primacy-Recency): Put the 3 most critical rules at both top and bottom of long prompts/protocols so instruction adherence survives long context windows. Goal-driven execution: Define success criteria first, loop until verified, and stop only when observable checks pass. Tests verify intent: Tests must protect business rules/invariants and fail when the protected intent breaks, not only mirror current behavior.

[LESSON-LEARNED-REMINDER] [BLOCKING] Task Planning & Continuous Improvement — MANDATORY. Do not skip.

Break work into small tasks (task tracking) before starting. Add final task: "Analyze AI mistakes & lessons learned".

Extract lessons — ROOT CAUSE ONLY, not symptom fixes:

1. Name the FAILURE MODE (reasoning/assumption failure), not symptom — "assumed API existed without reading source" not "used wrong enum value". 2. Generality test: does this failure mode apply to ≥3 contexts/codebases? If not, abstract one level up. 3. Write as a universal rule — strip project-specific names/paths/classes. Useful on any codebase. 4. Consolidate: multiple mistakes sharing one failure mode → ONE lesson. 5. Recurrence gate: "Would this recur in future session WITHOUT this reminder?" — No → skip $learn. 6. Auto-fix gate: "Could $code-review/$code-simplifier/$security/$lint catch this?" — Yes → improve review skill instead. 7. BOTH gates pass → ask user to run $learn. [TASK-PLANNING] [MANDATORY] BEFORE executing any workflow or skill step, create/update task tracking for all planned steps, then keep it synchronized as each step starts/completes.

<!-- CODEX:SYNC-PROMPT-PROTOCOLS:END -->

Common Media Processing Workflows

Video Optimization

Optimize for Web

# H.264 with good compression
ffmpeg -i input.mp4 \
  -c:v libx264 -preset slow -crf 23 \
  -c:a aac -b:a 128k \
  -movflags +faststart \
  output.mp4

Multi-Pass Encoding

# Pass 1 (analysis)
ffmpeg -y -i input.mkv -c:v libx264 -b:v 2600k -pass 1 -an -f null /dev/null

# Pass 2 (encoding)
ffmpeg -i input.mkv -c:v libx264 -b:v 2600k -pass 2 -c:a aac output.mp4

Hardware-Accelerated Encoding

# NVIDIA NVENC
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc -preset fast -crf 22 output.mp4

# Intel QuickSync
ffmpeg -hwaccel qsv -c:v h264_qsv -i input.mp4 -c:v h264_qsv output.mp4

Extract Video Segment

# From 1:30 to 3:00 (re-encode for precision)
ffmpeg -i input.mp4 -ss 00:01:30 -to 00:03:00 \
  -c:v libx264 -c:a aac output.mp4

Image Workflows

Create Responsive Images

# Generate multiple sizes
for size in 320 640 1024 1920; do
  magick input.jpg -resize ${size}x -quality 85 "output-${size}w.jpg"
done

Batch Image Optimization

# Convert PNG to optimized JPEG
mogrify -path ./optimized -format jpg -quality 85 -strip *.png

Complex Image Pipeline

# Resize, crop, border, adjust
magick input.jpg \
  -resize 1000x1000^ \
  -gravity center \
  -crop 1000x1000+0+0 +repage \
  -bordercolor black -border 5x5 \
  -brightness-contrast 5x10 \
  -quality 90 \
  output.jpg

GIF Creation

Video to GIF

# High quality GIF with palette
ffmpeg -i input.mp4 -vf "fps=15,scale=640:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" output.gif

Animated GIF from Images

# Create with delay
magick -delay 100 -loop 0 frame*.png animated.gif

# Optimize size
magick animated.gif -fuzz 5% -layers Optimize optimized.gif

Background Removal Workflows

Batch Background Removal

# Process all images in directory
for img in *.jpg; do
  rmbg "$img" -m modnet -o "${img%.jpg}-no-bg.png"
done

Product Photography

# 1. Remove background
rmbg product.jpg -m u2net-cloth -o product-no-bg.png

# 2. Resize to multiple sizes
magick product-no-bg.png -resize 800x800 product-800.png
magick product-no-bg.png -resize 400x400 product-400.png

# 3. Add white background if needed
magick product-no-bg.png -background white -flatten product-white-bg.jpg

Media Analysis

Inspect Video Properties

# Detailed JSON output
ffprobe -v quiet -print_format json -show_format -show_streams input.mp4

# Get resolution
ffprobe -v error -select_streams v:0 \
  -show_entries stream=width,height \
  -of csv=s=x:p=0 input.mp4

Image Information

# Basic info
identify image.jpg

# Detailed format
identify -verbose image.jpg

# Custom format
identify -format "%f: %wx%h %b\n" image.jpg

FFmpeg Video & Audio Encoding

Complete guide to codec selection, quality optimization, and hardware acceleration.

Video Codecs

H.264 (libx264)

Most widely supported codec, excellent compression/quality balance.

Best for: Universal compatibility, streaming, web video

Quality range: CRF 17-28 (lower = better)

# High quality
ffmpeg -i input.mkv -c:v libx264 -preset slow -crf 18 -c:a copy output.mp4

# Standard quality (recommended)
ffmpeg -i input.mkv -c:v libx264 -preset medium -crf 23 -c:a copy output.mp4

# Fast encoding
ffmpeg -i input.mkv -c:v libx264 -preset fast -crf 23 -c:a copy output.mp4

H.265/HEVC (libx265)

25-50% better compression than H.264, slower encoding.

Best for: 4K video, file size reduction, archival

# High quality 4K
ffmpeg -i input.mkv -c:v libx265 -preset medium -crf 24 -c:a copy output.mp4

# Balanced quality
ffmpeg -i input.mkv -c:v libx265 -preset fast -crf 26 -c:a copy output.mp4

VP9 (libvpx-vp9)

Royalty-free, WebM format, good for YouTube and open-source projects.

Best for: YouTube, Chrome/Firefox, open platforms

# Quality-based (recommended)
ffmpeg -i input.mkv -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus output.webm

# Two-pass for better quality
ffmpeg -i input.mkv -c:v libvpx-vp9 -b:v 2M -pass 1 -an -f null /dev/null
ffmpeg -i input.mkv -c:v libvpx-vp9 -b:v 2M -pass 2 -c:a libopus output.webm

AV1 (libaom-av1, libsvtav1)

Next-generation codec, best compression, very slow encoding.

Best for: Future-proofing, maximum compression, low bandwidth

# Using libaom (slow, highest quality)
ffmpeg -i input.mkv -c:v libaom-av1 -crf 30 -b:v 0 -strict experimental output.mp4

# Using SVT-AV1 (faster)
ffmpeg -i input.mkv -c:v libsvtav1 -crf 30 -preset 5 output.mp4

Audio Codecs

AAC (Industry Standard)

Best quality for streaming, universal support.

# High quality
ffmpeg -i input.mp4 -c:a aac -b:a 192k output.mp4

# Standard quality
ffmpeg -i input.mp4 -c:a aac -b:a 128k output.mp4

# Low bitrate
ffmpeg -i input.mp4 -c:a aac -b:a 96k output.mp4

MP3 (libmp3lame)

Universal compatibility, good quality.

# Variable bitrate (best quality)
ffmpeg -i input.wav -c:a libmp3lame -q:a 0 output.mp3

# Constant bitrate
ffmpeg -i input.wav -c:a libmp3lame -b:a 192k output.mp3

Opus (libopus)

Best quality at low bitrates, ideal for voice and streaming.

# Voice (mono)
ffmpeg -i input.mp4 -c:a libopus -b:a 32k -ac 1 output.webm

# Music (stereo)
ffmpeg -i input.mp4 -c:a libopus -b:a 128k output.webm

FLAC (Lossless)

No quality loss, archival quality, larger files.

# Lossless audio
ffmpeg -i input.wav -c:a flac output.flac

# Extract audio losslessly
ffmpeg -i video.mp4 -c:a flac audio.flac

Quality Optimization

CRF (Constant Rate Factor)

Best for quality-focused encoding. Single-pass, adjusts bitrate for complexity.

CRF Scale:

• 0 = Lossless (huge files)
• 17-18 = Visually lossless
• 20-23 = High quality (recommended)
• 24-28 = Medium quality
• 30+ = Low quality
• 51 = Worst quality

# Visually lossless
ffmpeg -i input.mp4 -c:v libx264 -crf 18 -preset slow output.mp4

# High quality (recommended)
ffmpeg -i input.mp4 -c:v libx264 -crf 22 -preset medium output.mp4

# Balanced quality/size
ffmpeg -i input.mp4 -c:v libx264 -crf 25 -preset fast output.mp4

Bitrate-Based Encoding

Target specific file size or quality. Two-pass recommended.

# Calculate target bitrate
# bitrate = (target_size_MB * 8192) / duration_seconds - audio_bitrate

# Two-pass encoding (2600k video, 128k audio)
ffmpeg -y -i input.mkv -c:v libx264 -b:v 2600k -pass 1 -an -f null /dev/null
ffmpeg -i input.mkv -c:v libx264 -b:v 2600k -pass 2 -c:a aac -b:a 128k output.mp4

Presets (Speed vs Compression)

Trade-off between encoding speed and file size.

Available presets:

• ultrafast - Fastest, largest files
• superfast
• veryfast
• faster
• fast
• medium - Default balance
• slow - Better compression
• slower
• veryslow - Best compression
• placebo - Not recommended (minimal gains)

# Fast encoding (real-time)
ffmpeg -i input.mp4 -c:v libx264 -preset ultrafast -crf 23 output.mp4

# Balanced
ffmpeg -i input.mp4 -c:v libx264 -preset medium -crf 22 output.mp4

# Best compression (slow)
ffmpeg -i input.mp4 -c:v libx264 -preset veryslow -crf 20 output.mp4

Hardware Acceleration

NVIDIA NVENC

5-10x faster encoding, slightly larger files than software encoding.

Requirements: NVIDIA GPU (GTX 10xx or newer)

# H.264 with NVENC
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc -preset fast -crf 22 output.mp4

# H.265 with NVENC
ffmpeg -hwaccel cuda -i input.mp4 -c:v hevc_nvenc -preset slow -crf 24 output.mp4

# Quality levels (instead of CRF)
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc -preset slow -rc vbr -cq 22 output.mp4

NVENC Presets:

• default - Balanced
• slow - Better quality
• medium
• fast
• hp - High performance
• hq - High quality
• bd - Bluray disk
• ll - Low latency
• llhq - Low latency high quality
• llhp - Low latency high performance

Intel QuickSync (QSV)

Fast hardware encoding on Intel CPUs with integrated graphics.

Requirements: Intel CPU with Quick Sync Video support

# H.264 with QSV
ffmpeg -hwaccel qsv -c:v h264_qsv -i input.mp4 \
  -c:v h264_qsv -preset fast -global_quality 22 output.mp4

# H.265 with QSV
ffmpeg -hwaccel qsv -c:v hevc_qsv -i input.mp4 \
  -c:v hevc_qsv -preset medium -global_quality 24 output.mp4

# Quality levels
ffmpeg -hwaccel qsv -i input.mp4 -c:v h264_qsv -global_quality 20 output.mp4

AMD VCE/VCN

Hardware encoding on AMD GPUs.

Requirements: AMD GPU with VCE/VCN support

# H.264 with AMF
ffmpeg -hwaccel auto -i input.mp4 \
  -c:v h264_amf -quality balanced -rc cqp -qp 22 output.mp4

# H.265 with AMF
ffmpeg -hwaccel auto -i input.mp4 \
  -c:v hevc_amf -quality quality -rc cqp -qp 24 output.mp4

Apple VideoToolbox (macOS)

Hardware encoding on macOS devices.

# H.264 with VideoToolbox
ffmpeg -i input.mp4 -c:v h264_videotoolbox -b:v 2M output.mp4

# H.265 with VideoToolbox
ffmpeg -i input.mp4 -c:v hevc_videotoolbox -b:v 1.5M output.mp4

Performance Tuning

Multi-Threading

FFmpeg automatically uses multiple cores. Override if needed:

# Limit threads
ffmpeg -threads 4 -i input.mp4 -c:v libx264 output.mp4

# Auto (default)
ffmpeg -threads 0 -i input.mp4 -c:v libx264 output.mp4

Tune Options

Optimize encoder for specific content types:

# Film content
ffmpeg -i input.mp4 -c:v libx264 -tune film -crf 22 output.mp4

# Animation
ffmpeg -i input.mp4 -c:v libx264 -tune animation -crf 22 output.mp4

# Grain (film with noise)
ffmpeg -i input.mp4 -c:v libx264 -tune grain -crf 22 output.mp4

# Low latency streaming
ffmpeg -i input.mp4 -c:v libx264 -tune zerolatency -crf 22 output.mp4

# Screen content (sharp edges)
ffmpeg -i input.mp4 -c:v libx264 -tune stillimage -crf 22 output.mp4

Codec Selection Guide

Use Cases

Platform Compatibility

Best Practices

1. Use CRF for most tasks - Better than bitrate for variable content 2. Start with CRF 23 - Good balance, adjust based on results 3. Use slow preset - For archival and final delivery 4. Use fast preset - For previews and testing 5. Hardware acceleration - When speed is critical 6. Two-pass encoding - When file size is fixed 7. Match source frame rate - Don't increase FPS 8. Don't upscale resolution - Keep original or downscale 9. Test on short clips - Verify settings before full encode 10. Keep source files - Original quality for re-encoding

Troubleshooting

Poor Quality Output

# Lower CRF value
ffmpeg -i input.mp4 -c:v libx264 -crf 18 -preset slow output.mp4

# Use slower preset
ffmpeg -i input.mp4 -c:v libx264 -crf 22 -preset veryslow output.mp4

# Increase bitrate (two-pass)
ffmpeg -y -i input.mp4 -c:v libx264 -b:v 5M -pass 1 -an -f null /dev/null
ffmpeg -i input.mp4 -c:v libx264 -b:v 5M -pass 2 -c:a aac output.mp4

Slow Encoding

# Use faster preset
ffmpeg -i input.mp4 -c:v libx264 -preset ultrafast output.mp4

# Use hardware acceleration
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc output.mp4

# Reduce resolution
ffmpeg -i input.mp4 -vf scale=1280:-1 -c:v libx264 output.mp4

Large File Size

# Increase CRF
ffmpeg -i input.mp4 -c:v libx264 -crf 26 output.mp4

# Use better codec
ffmpeg -i input.mp4 -c:v libx265 -crf 26 output.mp4

# Two-pass with target bitrate
ffmpeg -y -i input.mp4 -c:v libx264 -b:v 1M -pass 1 -an -f null /dev/null
ffmpeg -i input.mp4 -c:v libx264 -b:v 1M -pass 2 -c:a aac output.mp4

FFmpeg Filters & Effects

Complete guide to video and audio filters, complex filtergraphs, and effect chains.

Filter Basics

Filter Syntax

Filters are applied with -vf (video) or -af (audio).

# Single filter
ffmpeg -i input.mp4 -vf scale=1280:720 output.mp4

# Chain filters with comma
ffmpeg -i input.mp4 -vf "scale=1280:720,hqdn3d" output.mp4

# Complex filtergraph with -filter_complex
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "[0:v][1:v]overlay=10:10" \
  output.mp4

Video Filters

Scale (Resize)

Change video dimensions.

# Specific dimensions
ffmpeg -i input.mp4 -vf scale=1280:720 output.mp4

# Maintain aspect ratio (auto height)
ffmpeg -i input.mp4 -vf scale=1280:-1 output.mp4

# Maintain aspect ratio (auto width)
ffmpeg -i input.mp4 -vf scale=-1:720 output.mp4

# Scale to half
ffmpeg -i input.mp4 -vf scale=iw/2:ih/2 output.mp4

# Scale with algorithm
ffmpeg -i input.mp4 -vf scale=1280:-1:flags=lanczos output.mp4

Scaling algorithms:

• bilinear - Fast, default
• bicubic - Better quality
• lanczos - Best quality, slower

Crop

Extract portion of video.

# Crop width:height:x:y
ffmpeg -i input.mp4 -vf crop=1280:720:0:0 output.mp4

# Crop from center
ffmpeg -i input.mp4 -vf crop=1280:720:(iw-1280)/2:(ih-720)/2 output.mp4

# Auto-detect black borders
ffmpeg -i input.mp4 -vf cropdetect -f null -

# Apply detected crop
ffmpeg -i input.mp4 -vf crop=1920:800:0:140 output.mp4

Rotate & Flip

Change video orientation.

# Rotate 90° clockwise
ffmpeg -i input.mp4 -vf transpose=1 output.mp4

# Rotate 90° counter-clockwise
ffmpeg -i input.mp4 -vf transpose=2 output.mp4

# Rotate 180°
ffmpeg -i input.mp4 -vf transpose=1,transpose=1 output.mp4

# Flip horizontal
ffmpeg -i input.mp4 -vf hflip output.mp4

# Flip vertical
ffmpeg -i input.mp4 -vf vflip output.mp4

# Rotate arbitrary angle
ffmpeg -i input.mp4 -vf rotate=45*PI/180 output.mp4

Overlay (Watermark)

Composite images over video.

# Top-left corner
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex overlay=10:10 output.mp4

# Top-right corner
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex "overlay=W-w-10:10" output.mp4

# Bottom-right corner
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex "overlay=W-w-10:H-h-10" output.mp4

# Center
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex "overlay=(W-w)/2:(H-h)/2" output.mp4

# With transparency
ffmpeg -i video.mp4 -i logo.png \
  -filter_complex "[1:v]format=rgba,colorchannelmixer=aa=0.5[logo];[0:v][logo]overlay=10:10" \
  output.mp4

Denoise

Reduce video noise.

# High-quality denoise (hqdn3d)
ffmpeg -i input.mp4 -vf hqdn3d output.mp4

# Stronger denoise
ffmpeg -i input.mp4 -vf hqdn3d=4:3:6:4.5 output.mp4

# Temporal denoise (nlmeans - slow but best)
ffmpeg -i input.mp4 -vf nlmeans output.mp4

# Fast denoise
ffmpeg -i input.mp4 -vf dctdnoiz output.mp4

Deinterlace

Remove interlacing artifacts.

# YADIF (fast, good quality)
ffmpeg -i input.mp4 -vf yadif output.mp4

# YADIF with frame doubling
ffmpeg -i input.mp4 -vf yadif=1 output.mp4

# Bwdif (better quality)
ffmpeg -i input.mp4 -vf bwdif output.mp4

Speed & Slow Motion

Change playback speed.

# 2x speed (video + audio)
ffmpeg -i input.mp4 -vf setpts=0.5*PTS -af atempo=2.0 output.mp4

# 0.5x speed (slow motion)
ffmpeg -i input.mp4 -vf setpts=2.0*PTS -af atempo=0.5 output.mp4

# 4x speed (chain atempo)
ffmpeg -i input.mp4 -vf setpts=0.25*PTS -af atempo=2.0,atempo=2.0 output.mp4

Pad (Add Borders)

Add borders or letterbox.

# Add black borders to make 16:9
ffmpeg -i input.mp4 -vf "pad=1920:1080:(ow-iw)/2:(oh-ih)/2" output.mp4

# Add colored borders
ffmpeg -i input.mp4 -vf "pad=1920:1080:(ow-iw)/2:(oh-ih)/2:color=white" output.mp4

# Letterbox for Instagram (1:1)
ffmpeg -i input.mp4 -vf "scale=1080:-1,pad=1080:1080:(ow-iw)/2:(oh-ih)/2:color=black" output.mp4

Sharpen & Blur

Adjust image sharpness.

# Sharpen (unsharp mask)
ffmpeg -i input.mp4 -vf unsharp=5:5:1.0 output.mp4

# Stronger sharpen
ffmpeg -i input.mp4 -vf unsharp=7:7:2.5 output.mp4

# Gaussian blur
ffmpeg -i input.mp4 -vf gblur=sigma=8 output.mp4

# Box blur
ffmpeg -i input.mp4 -vf boxblur=5:1 output.mp4

Color Adjustments

Modify colors and exposure.

# Brightness (+/- 1.0)
ffmpeg -i input.mp4 -vf eq=brightness=0.1 output.mp4

# Contrast (+/- 2.0)
ffmpeg -i input.mp4 -vf eq=contrast=1.2 output.mp4

# Saturation (0-3)
ffmpeg -i input.mp4 -vf eq=saturation=1.5 output.mp4

# Gamma (0.1-10)
ffmpeg -i input.mp4 -vf eq=gamma=1.2 output.mp4

# Combined adjustments
ffmpeg -i input.mp4 -vf eq=brightness=0.05:contrast=1.1:saturation=1.2 output.mp4

# Curves (color grading)
ffmpeg -i input.mp4 -vf curves=vintage output.mp4

# Hue shift
ffmpeg -i input.mp4 -vf hue=h=90 output.mp4

Grayscale & Effects

Convert to monochrome or apply effects.

# Grayscale
ffmpeg -i input.mp4 -vf hue=s=0 output.mp4

# Sepia tone
ffmpeg -i input.mp4 -vf colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131 output.mp4

# Negative
ffmpeg -i input.mp4 -vf negate output.mp4

# Edge detection
ffmpeg -i input.mp4 -vf edgedetect output.mp4

# Vignette
ffmpeg -i input.mp4 -vf vignette output.mp4

Fade In/Out

Smooth transitions.

# Fade in from black (2 seconds)
ffmpeg -i input.mp4 -vf fade=in:0:60 output.mp4

# Fade out to black (last 2 seconds)
ffmpeg -i input.mp4 -vf fade=out:st=28:d=2 output.mp4

# Both fade in and out
ffmpeg -i input.mp4 -vf "fade=in:0:30,fade=out:st=28:d=2" output.mp4

Stabilization

Reduce camera shake.

# Two-pass stabilization
# Pass 1: detect motion
ffmpeg -i input.mp4 -vf vidstabdetect=shakiness=10:accuracy=15 -f null -

# Pass 2: stabilize
ffmpeg -i input.mp4 -vf vidstabtransform=smoothing=30:input="transforms.trf" output.mp4

Text Overlay

Add text to video.

# Simple text
ffmpeg -i input.mp4 -vf "drawtext=text='Hello World':fontsize=24:x=10:y=10" output.mp4

# With styling
ffmpeg -i input.mp4 -vf "drawtext=text='Title':fontsize=48:fontcolor=white:x=(w-text_w)/2:y=50:box=1:boxcolor=black@0.5:boxborderw=5" output.mp4

# Timestamp
ffmpeg -i input.mp4 -vf "drawtext=text='%{pts\:hms}':fontsize=20:x=10:y=10:fontcolor=white" output.mp4

Audio Filters

Volume

Adjust audio level.

# Increase by 10dB
ffmpeg -i input.mp4 -af volume=10dB output.mp4

# Decrease to 50%
ffmpeg -i input.mp4 -af volume=0.5 output.mp4

# Double volume
ffmpeg -i input.mp4 -af volume=2.0 output.mp4

Normalize

Balance audio levels.

# Loudness normalization (EBU R128)
ffmpeg -i input.mp4 -af loudnorm output.mp4

# With specific target
ffmpeg -i input.mp4 -af loudnorm=I=-16:TP=-1.5:LRA=11 output.mp4

# Two-pass normalization (better quality)
# Pass 1: analyze
ffmpeg -i input.mp4 -af loudnorm=print_format=json -f null -

# Pass 2: normalize with measured values
ffmpeg -i input.mp4 -af loudnorm=measured_I=-23:measured_LRA=7:measured_TP=-2:measured_thresh=-33 output.mp4

Equalizer

Adjust frequency bands.

# Bass boost
ffmpeg -i input.mp4 -af equalizer=f=100:width_type=h:width=200:g=10 output.mp4

# Treble boost
ffmpeg -i input.mp4 -af equalizer=f=10000:width_type=h:width=2000:g=5 output.mp4

# Multiple bands
ffmpeg -i input.mp4 -af "equalizer=f=100:g=5,equalizer=f=1000:g=-3" output.mp4

Compressor

Dynamic range compression.

# Basic compression
ffmpeg -i input.mp4 -af acompressor output.mp4

# Custom settings
ffmpeg -i input.mp4 -af acompressor=threshold=-20dB:ratio=4:attack=200:release=1000 output.mp4

Noise Reduction

Remove background noise.

# High-pass filter (remove low frequency noise)
ffmpeg -i input.mp4 -af highpass=f=200 output.mp4

# Low-pass filter (remove high frequency noise)
ffmpeg -i input.mp4 -af lowpass=f=3000 output.mp4

# Band-pass filter
ffmpeg -i input.mp4 -af "highpass=f=200,lowpass=f=3000" output.mp4

Fade Audio

Smooth audio transitions.

# Fade in (2 seconds)
ffmpeg -i input.mp4 -af afade=t=in:st=0:d=2 output.mp4

# Fade out (last 3 seconds)
ffmpeg -i input.mp4 -af afade=t=out:st=27:d=3 output.mp4

# Both
ffmpeg -i input.mp4 -af "afade=t=in:st=0:d=2,afade=t=out:st=27:d=3" output.mp4

Audio Mixing

Combine multiple audio tracks.

# Mix two audio files
ffmpeg -i audio1.mp3 -i audio2.mp3 \
  -filter_complex amix=inputs=2:duration=longest output.mp3

# Mix with volume adjustment
ffmpeg -i audio1.mp3 -i audio2.mp3 \
  -filter_complex "[0:a]volume=0.8[a1];[1:a]volume=0.5[a2];[a1][a2]amix=inputs=2" \
  output.mp3

Complex Filtergraphs

Multiple Outputs

Create multiple versions simultaneously.

# Generate 3 resolutions at once
ffmpeg -i input.mp4 \
  -filter_complex "[0:v]split=3[v1][v2][v3]; \
    [v1]scale=1920:1080[out1]; \
    [v2]scale=1280:720[out2]; \
    [v3]scale=640:360[out3]" \
  -map "[out1]" -c:v libx264 -crf 22 output_1080p.mp4 \
  -map "[out2]" -c:v libx264 -crf 23 output_720p.mp4 \
  -map "[out3]" -c:v libx264 -crf 24 output_360p.mp4 \
  -map 0:a -c:a copy

Picture-in-Picture

Overlay small video on main video.

ffmpeg -i main.mp4 -i small.mp4 \
  -filter_complex "[1:v]scale=320:180[pip]; \
    [0:v][pip]overlay=W-w-10:H-h-10" \
  output.mp4

Side-by-Side Comparison

Compare two videos.

# Horizontal
ffmpeg -i left.mp4 -i right.mp4 \
  -filter_complex "[0:v][1:v]hstack=inputs=2" \
  output.mp4

# Vertical
ffmpeg -i top.mp4 -i bottom.mp4 \
  -filter_complex "[0:v][1:v]vstack=inputs=2" \
  output.mp4

Crossfade Transition

Smooth transition between videos.

ffmpeg -i video1.mp4 -i video2.mp4 \
  -filter_complex "[0:v][1:v]xfade=transition=fade:duration=2:offset=8" \
  output.mp4

Transition types: fade, wipeleft, wiperight, wipeup, wipedown, slideleft, slideright, slideup, slidedown, circlecrop, rectcrop, distance, fadeblack, fadewhite, radial, smoothleft, smoothright, smoothup, smoothdown

Color Correction Pipeline

Professional color grading.

ffmpeg -i input.mp4 \
  -filter_complex "[0:v]eq=contrast=1.1:brightness=0.05:saturation=1.2[v1]; \
    [v1]curves=vintage[v2]; \
    [v2]vignette[v3]; \
    [v3]unsharp=5:5:1.0[out]" \
  -map "[out]" -c:v libx264 -crf 18 output.mp4

Filter Performance

GPU Acceleration

Use hardware filters when available.

# NVIDIA CUDA scale
ffmpeg -hwaccel cuda -i input.mp4 \
  -vf scale_cuda=1280:720 \
  -c:v h264_nvenc output.mp4

# Multiple GPU filters
ffmpeg -hwaccel cuda -i input.mp4 \
  -vf "scale_cuda=1280:720,hwdownload,format=nv12" \
  -c:v h264_nvenc output.mp4

Optimize Filter Order

More efficient filter chains.

# Bad: scale after complex operations
ffmpeg -i input.mp4 -vf "hqdn3d,unsharp=5:5:1.0,scale=1280:720" output.mp4

# Good: scale first (fewer pixels to process)
ffmpeg -i input.mp4 -vf "scale=1280:720,hqdn3d,unsharp=5:5:1.0" output.mp4

Common Filter Recipes

YouTube Optimized

ffmpeg -i input.mp4 \
  -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2" \
  -c:v libx264 -preset slow -crf 18 -c:a aac -b:a 192k \
  output.mp4

Instagram Portrait

ffmpeg -i input.mp4 \
  -vf "scale=1080:1350:force_original_aspect_ratio=decrease,pad=1080:1350:(ow-iw)/2:(oh-ih)/2:color=white" \
  -c:v libx264 -preset fast -crf 23 -c:a aac \
  output.mp4

Vintage Film Look

ffmpeg -i input.mp4 \
  -vf "curves=vintage,vignette=angle=PI/4,eq=saturation=0.8,noise=alls=10:allf=t" \
  -c:v libx264 -crf 20 output.mp4

Clean & Enhance

ffmpeg -i input.mp4 \
  -vf "hqdn3d=4:3:6:4.5,unsharp=5:5:1.0,eq=contrast=1.05:saturation=1.1" \
  -c:v libx264 -crf 20 output.mp4

FFmpeg Streaming & Live Video

Complete guide to HLS/DASH streaming, live streaming platforms, and adaptive bitrate encoding.

HLS (HTTP Live Streaming)

Basic HLS Stream

Generate playlist for on-demand streaming.

# Simple HLS with default settings
ffmpeg -i input.mp4 \
  -c:v libx264 -c:a aac \
  -f hls -hls_time 6 -hls_playlist_type vod \
  -hls_segment_filename "segment_%03d.ts" \
  playlist.m3u8

Key parameters:

• -hls_time - Segment duration (seconds, default 2)
• -hls_playlist_type - vod (on-demand) or event (live)
• -hls_segment_filename - Naming pattern for segments

Optimized HLS

Better quality and compatibility.

ffmpeg -i input.mp4 \
  -c:v libx264 -preset fast -crf 22 \
  -g 48 -sc_threshold 0 \
  -c:a aac -b:a 128k \
  -f hls -hls_time 6 -hls_playlist_type vod \
  -hls_segment_filename "segment_%03d.ts" \
  playlist.m3u8

Parameters explained:

• -g 48 - Keyframe every 48 frames (2s @ 24fps)
• -sc_threshold 0 - Disable scene detection (consistent segments)

Multi-Bitrate HLS (Adaptive)

Create multiple quality levels for adaptive streaming.

ffmpeg -i input.mp4 \
  -map 0:v -map 0:a -map 0:v -map 0:a -map 0:v -map 0:a \
  -c:v libx264 -crf 22 -c:a aac -b:a 128k \
  -b:v:0 800k  -s:v:0 640x360   -maxrate:v:0 856k  -bufsize:v:0 1200k \
  -b:v:1 1400k -s:v:1 842x480   -maxrate:v:1 1498k -bufsize:v:1 2100k \
  -b:v:2 2800k -s:v:2 1280x720  -maxrate:v:2 2996k -bufsize:v:2 4200k \
  -var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" \
  -master_pl_name master.m3u8 \
  -f hls -hls_time 6 -hls_list_size 0 \
  -hls_segment_filename "stream_%v/segment_%03d.ts" \
  stream_%v/playlist.m3u8

Creates:

• master.m3u8 - Master playlist (entry point)
• stream_0/playlist.m3u8 - 360p stream
• stream_1/playlist.m3u8 - 480p stream
• stream_2/playlist.m3u8 - 720p stream

HLS with Encryption

Protect content with AES-128 encryption.

# Generate encryption key
openssl rand 16 > enc.key
echo "enc.key" > enc.keyinfo
echo "enc.key" >> enc.keyinfo
openssl rand -hex 16 >> enc.keyinfo

# Encode with encryption
ffmpeg -i input.mp4 \
  -c:v libx264 -c:a aac \
  -f hls -hls_time 6 \
  -hls_key_info_file enc.keyinfo \
  -hls_segment_filename "segment_%03d.ts" \
  playlist.m3u8

DASH (Dynamic Adaptive Streaming)

Basic DASH

MPEG-DASH format for adaptive streaming.

ffmpeg -i input.mp4 \
  -c:v libx264 -c:a aac \
  -f dash -seg_duration 6 \
  -use_template 1 -use_timeline 1 \
  manifest.mpd

Multi-Bitrate DASH

Multiple quality levels.

ffmpeg -i input.mp4 \
  -map 0:v -map 0:a -map 0:v -map 0:a \
  -c:v libx264 -c:a aac \
  -b:v:0 800k  -s:v:0 640x360 \
  -b:v:1 1400k -s:v:1 1280x720 \
  -b:a:0 128k -b:a:1 128k \
  -f dash -seg_duration 6 \
  -use_template 1 -use_timeline 1 \
  manifest.mpd

RTMP Live Streaming

Stream to Twitch

ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset veryfast -maxrate 3000k -bufsize 6000k \
  -pix_fmt yuv420p -g 50 -c:a aac -b:a 128k -ar 44100 \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Stream to YouTube

ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset veryfast -maxrate 2500k -bufsize 5000k \
  -pix_fmt yuv420p -g 60 -c:a aac -b:a 128k \
  -f flv rtmp://a.rtmp.youtube.com/live2/STREAM_KEY

Stream to Facebook

ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset veryfast -maxrate 4000k -bufsize 8000k \
  -pix_fmt yuv420p -g 60 -c:a aac -b:a 128k \
  -f flv rtmps://live-api-s.facebook.com:443/rtmp/STREAM_KEY

Custom RTMP Server

ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset veryfast -tune zerolatency \
  -maxrate 2500k -bufsize 5000k \
  -pix_fmt yuv420p -g 50 \
  -c:a aac -b:a 128k -ar 44100 \
  -f flv rtmp://your-server.com/live/stream-key

Screen Capture + Stream

Linux (X11)

ffmpeg -f x11grab -s 1920x1080 -framerate 30 -i :0.0 \
  -f pulse -ac 2 -i default \
  -c:v libx264 -preset veryfast -tune zerolatency \
  -maxrate 2500k -bufsize 5000k -pix_fmt yuv420p \
  -c:a aac -b:a 128k -ar 44100 \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

macOS (AVFoundation)

# List devices
ffmpeg -f avfoundation -list_devices true -i ""

# Capture and stream
ffmpeg -f avfoundation -framerate 30 -i "1:0" \
  -c:v libx264 -preset veryfast -tune zerolatency \
  -maxrate 2500k -bufsize 5000k -pix_fmt yuv420p \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Windows (DirectShow)

ffmpeg -f dshow -i video="screen-capture-recorder":audio="Stereo Mix" \
  -c:v libx264 -preset ultrafast -tune zerolatency \
  -maxrate 750k -bufsize 3000k \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Thumbnail Generation

Single Thumbnail

Extract frame at specific time.

# At 5 seconds
ffmpeg -ss 00:00:05 -i input.mp4 -vframes 1 -vf scale=320:-1 thumb.jpg

# At 10% duration
ffmpeg -ss $(ffprobe -v error -show_entries format=duration \
  -of default=noprint_wrappers=1:nokey=1 input.mp4 | \
  awk '{print $1*0.1}') -i input.mp4 -vframes 1 thumb.jpg

Multiple Thumbnails

Generate thumbnails at intervals.

# One per minute
ffmpeg -i input.mp4 -vf fps=1/60,scale=320:-1 thumb_%03d.jpg

# One per 10 seconds
ffmpeg -i input.mp4 -vf fps=1/10,scale=320:-1 thumb_%03d.jpg

# First 10 frames
ffmpeg -i input.mp4 -vframes 10 -vf scale=320:-1 thumb_%02d.jpg

Thumbnail Sprite Sheet

Create single image with multiple thumbnails.

# Generate frames
ffmpeg -i input.mp4 -vf fps=1/10,scale=160:90 frames/thumb_%03d.jpg

# Combine into sprite (requires ImageMagick)
montage frames/thumb_*.jpg -tile 5x -geometry +0+0 sprite.jpg

Preview Generation

Video Preview (Trailer)

Extract multiple short clips.

# Extract 3 segments
ffmpeg -i input.mp4 \
  -ss 00:00:30 -t 00:00:10 -c copy segment1.mp4
ffmpeg -i input.mp4 \
  -ss 00:05:00 -t 00:00:10 -c copy segment2.mp4
ffmpeg -i input.mp4 \
  -ss 00:10:00 -t 00:00:10 -c copy segment3.mp4

# Concatenate segments
echo "file 'segment1.mp4'" > concat.txt
echo "file 'segment2.mp4'" >> concat.txt
echo "file 'segment3.mp4'" >> concat.txt
ffmpeg -f concat -safe 0 -i concat.txt -c copy preview.mp4

Fast Preview (Low Quality)

Quick preview for review.

ffmpeg -i input.mp4 \
  -vf scale=640:-1 \
  -c:v libx264 -preset ultrafast -crf 28 \
  -c:a aac -b:a 64k \
  preview.mp4

Streaming Parameters

Important RTMP Parameters

Real-time reading:

• -re - Read input at native frame rate

Low latency:

• -tune zerolatency - Optimize for minimal latency
• -preset ultrafast or veryfast - Fast encoding

Keyframes:

• -g 50 - Keyframe interval (GOP size)
• Recommended: 2 seconds (fps \* 2)

Rate control:

• -maxrate - Maximum bitrate (e.g., 3000k)
• -bufsize - Buffer size (typically 2x maxrate)

Compatibility:

• -pix_fmt yuv420p - Compatible pixel format

Bitrate Recommendations

1080p 60fps:

• 4500-6000 kbps video
• 160 kbps audio

1080p 30fps:

• 3000-4500 kbps video
• 128 kbps audio

720p 60fps:

• 2500-4000 kbps video
• 128 kbps audio

720p 30fps:

• 1500-2500 kbps video
• 128 kbps audio

480p:

• 500-1000 kbps video
• 128 kbps audio

UDP/RTP Streaming

UDP Stream

Simple network streaming.

# Sender
ffmpeg -re -i input.mp4 -c copy -f mpegts udp://192.168.1.100:1234

# Receiver
ffplay udp://192.168.1.100:1234

RTP Stream

Real-Time Protocol for low latency.

# Audio only
ffmpeg -re -i audio.mp3 -c:a libopus -f rtp rtp://192.168.1.100:5004

# Video + audio
ffmpeg -re -i input.mp4 \
  -c:v libx264 -preset ultrafast \
  -c:a aac -f rtp rtp://192.168.1.100:5004

Multicast Stream

Stream to multiple receivers.

# Sender (multicast address)
ffmpeg -re -i input.mp4 -c copy -f mpegts udp://239.255.0.1:1234

# Receiver
ffplay udp://239.255.0.1:1234

Advanced Streaming

Hardware-Accelerated Streaming

Use GPU for faster encoding.

# NVIDIA NVENC
ffmpeg -re -i input.mp4 \
  -c:v h264_nvenc -preset fast -maxrate 3000k -bufsize 6000k \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

# Intel QSV
ffmpeg -re -hwaccel qsv -i input.mp4 \
  -c:v h264_qsv -preset fast -maxrate 3000k -bufsize 6000k \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Stream with Overlay

Add graphics during stream.

ffmpeg -re -i input.mp4 -i logo.png \
  -filter_complex "[0:v][1:v]overlay=10:10" \
  -c:v libx264 -preset veryfast -maxrate 3000k \
  -c:a copy \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Loop Stream

Continuously loop video for 24/7 stream.

ffmpeg -stream_loop -1 -re -i input.mp4 \
  -c:v libx264 -preset veryfast -maxrate 2500k \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.twitch.tv/app/STREAM_KEY

Troubleshooting

Buffering Issues

# Reduce buffer size
ffmpeg -re -i input.mp4 -maxrate 2000k -bufsize 2000k -c:v libx264 -f flv rtmp://...

# Use faster preset
ffmpeg -re -i input.mp4 -preset ultrafast -c:v libx264 -f flv rtmp://...

Audio/Video Desync

# Force constant frame rate
ffmpeg -re -i input.mp4 -r 30 -c:v libx264 -f flv rtmp://...

# Use -vsync 1
ffmpeg -re -i input.mp4 -vsync 1 -c:v libx264 -f flv rtmp://...

Connection Drops

# Increase timeout
ffmpeg -timeout 5000000 -re -i input.mp4 -c:v libx264 -f flv rtmp://...

# Reconnect on failure (use wrapper script)
while true; do
  ffmpeg -re -i input.mp4 -c:v libx264 -f flv rtmp://...
  sleep 5
done

Format Compatibility & Conversion Guide

Complete guide to media format support, codec recommendations, and conversion best practices.

Image Format Support

ImageMagick Formats

Raster Formats (Full Support):

• JPEG (.jpg, .jpeg) - Lossy, universal
• PNG (.png) - Lossless, transparency
• WebP (.webp) - Modern, lossy/lossless
• GIF (.gif) - Animation, limited colors
• TIFF (.tif, .tiff) - Professional, lossless
• BMP (.bmp) - Uncompressed, legacy
• ICO (.ico) - Icons, multi-size

Raw Formats (Read Support):

• CR2, NEF, ARW, DNG (Canon, Nikon, Sony, Adobe RAW)
• Requires dcraw or ufraw-batch

Vector Formats (Limited):

• SVG (.svg) - Read only, converts to raster
• PDF (.pdf) - Read/write, may have policy restrictions

Other Formats:

• HEIC (.heic) - Apple format, requires libheif
• AVIF (.avif) - Next-gen, requires libavif
• PSD (.psd) - Photoshop, basic support

FFmpeg Image Support

Input Formats:

• JPEG, PNG, BMP, TIFF, WebP, GIF
• Image sequences (frame\_%04d.png)

Output Formats:

• JPEG, PNG, BMP, TIFF
• Video from images

Video Format Support

Container Formats

Universal Containers:

• MP4 (.mp4) - Most compatible, streaming
• MKV (.mkv) - Feature-rich, flexible
• WebM (.webm) - Web-optimized, open
• AVI (.avi) - Legacy, broad support
• MOV (.mov) - Apple, professional

Streaming Containers:

• TS (.ts) - Transport stream, HLS segments
• M3U8 (.m3u8) - HLS playlist
• MPD (.mpd) - DASH manifest
• FLV (.flv) - Flash (legacy)

Professional Formats:

• ProRes (.mov) - Apple professional
• DNxHD/DNxHR (.mxf, .mov) - Avid professional
• MXF (.mxf) - Broadcast

Video Codecs

Modern Codecs:

• H.264/AVC (libx264) - Universal, excellent balance
• H.265/HEVC (libx265) - Better compression, 4K
• VP9 (libvpx-vp9) - Open, YouTube
• AV1 (libaom-av1, libsvtav1) - Next-gen, best compression

Legacy Codecs:

• MPEG-4 (mpeg4) - Older devices
• MPEG-2 (mpeg2video) - DVD, broadcast
• VP8 (libvpx) - WebM predecessor

Professional Codecs:

• ProRes (prores) - Apple post-production
• DNxHD (dnxhd) - Avid editing
• Uncompressed (rawvideo) - Maximum quality

Audio Codecs

Modern Codecs:

• AAC (aac) - Universal, streaming
• Opus (libopus) - Best low-bitrate
• MP3 (libmp3lame) - Universal compatibility

Lossless Codecs:

• FLAC (flac) - Open, archival
• ALAC (alac) - Apple lossless
• WAV (pcm_s16le) - Uncompressed

Other Codecs:

• Vorbis (libvorbis) - Open, WebM
• AC-3 (ac3) - Dolby Digital, surround
• DTS (dts) - Cinema surround

Format Recommendations

Use Case Matrix

Platform Compatibility

Web Browsers (2025):

• Images: JPEG, PNG, WebP, GIF, SVG
• Video: MP4 (H.264), WebM (VP9), MP4 (AV1)
• Audio: AAC, MP3, Opus, Vorbis

Mobile Devices:

• iOS: JPEG, PNG, HEIC, MP4 (H.264/H.265), AAC
• Android: JPEG, PNG, WebP, MP4 (H.264/H.265), AAC

Smart TVs:

• Most: MP4 (H.264), AAC
• Modern: MP4 (H.265), AC-3

Social Media:

• All platforms: JPEG, MP4 (H.264), AAC

Quality vs Size Trade-offs

Image Quality Comparison

JPEG Quality Levels:

• 95-100: ~5-10 MB (large image), minimal artifacts
• 85-94: ~1-3 MB, imperceptible loss
• 75-84: ~500 KB-1 MB, slight artifacts
• 60-74: ~200-500 KB, visible artifacts
• Below 60: <200 KB, poor quality

Format Comparison (Same quality):

• WebP: 25-35% smaller than JPEG
• HEIC: 40-50% smaller than JPEG
• AVIF: 50-60% smaller than JPEG
• PNG: 2-5x larger than JPEG (lossless)

Video Quality Comparison

H.264 CRF Values:

• CRF 18: Visually lossless, ~8-15 Mbps (1080p)
• CRF 23: High quality, ~4-8 Mbps (1080p)
• CRF 28: Medium quality, ~2-4 Mbps (1080p)

Codec Comparison (Same quality):

• H.265: 40-50% smaller than H.264
• VP9: 30-40% smaller than H.264
• AV1: 50-60% smaller than H.264

Audio Quality Comparison

AAC Bitrates:

• 320 kbps: Transparent, archival
• 192 kbps: High quality, music
• 128 kbps: Good quality, streaming
• 96 kbps: Acceptable, low bandwidth
• 64 kbps: Poor, voice only

Codec Efficiency (Same quality):

• Opus: Best at low bitrates (<128k)
• AAC: Best overall balance
• MP3: Less efficient but universal

Conversion Best Practices

Image Conversions

PNG to JPEG:

# Standard conversion
magick input.png -quality 85 -strip output.jpg

# With transparency handling
magick input.png -background white -flatten -quality 85 output.jpg

JPEG to WebP:

# FFmpeg
ffmpeg -i input.jpg -quality 80 output.webp

# ImageMagick
magick input.jpg -quality 80 output.webp

RAW to JPEG:

# Requires dcraw
magick input.CR2 -quality 90 output.jpg

HEIC to JPEG:

# Requires libheif
magick input.heic -quality 85 output.jpg

Video Conversions

MKV to MP4:

# Copy streams (fast)
ffmpeg -i input.mkv -c copy output.mp4

# Re-encode if needed
ffmpeg -i input.mkv -c:v libx264 -crf 23 -c:a aac output.mp4

AVI to MP4:

# Modern codecs
ffmpeg -i input.avi -c:v libx264 -crf 23 -c:a aac output.mp4

MOV to MP4:

# Copy if H.264 already
ffmpeg -i input.mov -c copy output.mp4

# Convert ProRes to H.264
ffmpeg -i input.mov -c:v libx264 -crf 18 -c:a aac output.mp4

Any to WebM:

# VP9 encoding
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus output.webm

Audio Conversions

Extract Audio from Video:

# Keep original codec
ffmpeg -i video.mp4 -vn -c:a copy audio.m4a

# Convert to MP3
ffmpeg -i video.mp4 -vn -q:a 0 audio.mp3

# Convert to FLAC (lossless)
ffmpeg -i video.mp4 -vn -c:a flac audio.flac

Audio Format Conversion:

# WAV to MP3
ffmpeg -i input.wav -c:a libmp3lame -b:a 192k output.mp3

# MP3 to AAC
ffmpeg -i input.mp3 -c:a aac -b:a 192k output.m4a

# Any to Opus
ffmpeg -i input.wav -c:a libopus -b:a 128k output.opus

Codec Selection Guide

Choose H.264 When:

• Maximum compatibility needed
• Targeting older devices
• Streaming to unknown devices
• Social media upload
• Fast encoding required

Choose H.265 When:

• 4K video encoding
• Storage space limited
• Modern device targets
• Archival quality needed
• Bandwidth constrained

Choose VP9 When:

• YouTube upload
• Open-source requirement
• Chrome/Firefox primary
• Royalty-free needed

Choose AV1 When:

• Future-proofing content
• Maximum compression needed
• Encoding time not critical
• Modern platform targets

Format Migration Strategies

Archive to Web

# High-res archive -> Web-optimized
for img in archive/*.tif; do
  base=$(basename "$img" .tif)
  magick "$img" -resize 2000x2000\> -quality 85 -strip "web/${base}.jpg"
  magick "$img" -resize 2000x2000\> -quality 85 "web/${base}.webp"
done

Legacy to Modern

# Convert old formats to modern codecs
for video in legacy/*.avi; do
  base=$(basename "$video" .avi)
  ffmpeg -i "$video" \
    -c:v libx264 -crf 23 -preset slow \
    -c:a aac -b:a 128k \
    "modern/${base}.mp4"
done

Multi-Format Publishing

# Create multiple formats for compatibility
input="source.mp4"

# Modern browsers
ffmpeg -i "$input" -c:v libx264 -crf 23 -c:a aac output.mp4
ffmpeg -i "$input" -c:v libvpx-vp9 -crf 30 -c:a libopus output.webm

# Images
ffmpeg -ss 5 -i "$input" -vframes 1 poster.jpg
magick poster.jpg -quality 80 poster.webp

Troubleshooting

Unsupported Format

# Check FFmpeg formats
ffmpeg -formats

# Check ImageMagick formats
magick identify -list format

# Install missing codec support
sudo apt-get install libx264-dev libx265-dev libvpx-dev

Compatibility Issues

# Force compatible encoding
ffmpeg -i input.mp4 \
  -c:v libx264 -profile:v high -level 4.0 \
  -pix_fmt yuv420p \
  -c:a aac -b:a 128k \
  output.mp4

Quality Loss

# Avoid multiple conversions
# Bad: source -> edit -> web -> social
# Good: source -> final (single conversion)

# Use lossless intermediate
ffmpeg -i source.mp4 -c:v ffv1 intermediate.mkv
# Edit intermediate
ffmpeg -i intermediate.mkv -c:v libx264 final.mp4

ImageMagick Batch Processing

Complete guide to batch operations, mogrify command, parallel processing, and automation.

Mogrify Command

Basic Mogrify

Modify files in-place (overwrites originals).

# Resize all JPEGs
mogrify -resize 800x600 *.jpg

# Convert format (creates new files)
mogrify -format png *.jpg

# Apply effect to all images
mogrify -quality 85 -strip *.jpg

Warning: mogrify modifies files in-place. Always backup originals or use -path to output to different directory.

Output to Different Directory

Preserve originals.

# Create output directory first
mkdir output

# Process to output directory
mogrify -path ./output -resize 800x600 *.jpg

# With format conversion
mogrify -path ./optimized -format webp -quality 80 *.png

Common Batch Operations

Resize All Images

# Resize to width 800
mogrify -resize 800x *.jpg

# Resize to height 600
mogrify -resize x600 *.jpg

# Fit within 800×600
mogrify -resize 800x600 *.jpg

# Resize to exact dimensions
mogrify -resize 800x600! *.jpg

# Only shrink, never enlarge
mogrify -resize 800x600\> *.jpg

Format Conversion

# PNG to JPEG
mogrify -path ./jpg -format jpg -quality 85 *.png

# JPEG to WebP
mogrify -path ./webp -format webp -quality 80 *.jpg

# Any format to PNG
mogrify -path ./png -format png *.{jpg,gif,bmp}

Optimize Images

# Strip metadata from all JPEGs
mogrify -strip *.jpg

# Optimize JPEGs for web
mogrify -quality 85 -strip -interlace Plane *.jpg

# Compress PNGs
mogrify -quality 95 *.png

# Combined optimization
mogrify -quality 85 -strip -interlace Plane -sampling-factor 4:2:0 *.jpg

Apply Effects

# Add watermark to all images
mogrify -gravity southeast -draw "image over 10,10 0,0 'watermark.png'" *.jpg

# Convert all to grayscale
mogrify -colorspace Gray *.jpg

# Apply sepia tone
mogrify -sepia-tone 80% *.jpg

# Sharpen all images
mogrify -sharpen 0x1 *.jpg

Thumbnail Generation

# Create square thumbnails
mogrify -path ./thumbnails -resize 200x200^ -gravity center -extent 200x200 *.jpg

# Create thumbnails with max dimension
mogrify -path ./thumbs -thumbnail 300x300 *.jpg

# Thumbnails with quality control
mogrify -path ./thumbs -thumbnail 200x200 -quality 80 -strip *.jpg

Shell Loops

Basic For Loop

More control than mogrify.

# Resize with custom naming
for img in *.jpg; do
  magick "$img" -resize 800x600 "resized_$img"
done

# Process to subdirectory
mkdir processed
for img in *.jpg; do
  magick "$img" -resize 1920x1080 "processed/$img"
done

Multiple Operations

# Complex processing pipeline
for img in *.jpg; do
  magick "$img" \
    -resize 1920x1080^ \
    -gravity center \
    -crop 1920x1080+0+0 +repage \
    -unsharp 0x1 \
    -quality 85 -strip \
    "processed_$img"
done

Format Conversion with Rename

# Convert PNG to JPEG with new names
for img in *.png; do
  magick "$img" -quality 90 "${img%.png}.jpg"
done

# Add prefix during conversion
for img in *.jpg; do
  magick "$img" -resize 800x "web_${img}"
done

Conditional Processing

# Only process large images
for img in *.jpg; do
  width=$(identify -format "%w" "$img")
  if [ $width -gt 2000 ]; then
    magick "$img" -resize 2000x "resized_$img"
  fi
done

# Skip existing output files
for img in *.jpg; do
  output="output_$img"
  if [ ! -f "$output" ]; then
    magick "$img" -resize 800x "$output"
  fi
done

Parallel Processing

GNU Parallel

Process multiple images simultaneously.

# Install GNU Parallel
# Ubuntu/Debian: sudo apt-get install parallel
# macOS: brew install parallel

# Basic parallel resize
parallel magick {} -resize 800x600 resized_{} ::: *.jpg

# Parallel with function
resize_image() {
  magick "$1" -resize 1920x1080 -quality 85 "processed_$1"
}
export -f resize_image
parallel resize_image ::: *.jpg

# Limit concurrent jobs
parallel -j 4 magick {} -resize 800x {} ::: *.jpg

# Progress indicator
parallel --progress magick {} -resize 800x {} ::: *.jpg

Xargs Parallel

# Using xargs for parallel processing
ls *.jpg | xargs -I {} -P 4 magick {} -resize 800x processed_{}

# With find
find . -name "*.jpg" -print0 | \
  xargs -0 -I {} -P 4 magick {} -resize 800x {}

Advanced Batch Patterns

Recursive Processing

# Process all JPEGs in subdirectories
find . -name "*.jpg" -exec magick {} -resize 800x {} \;

# With output directory structure
find . -name "*.jpg" -type f | while read img; do
  outdir="output/$(dirname "$img")"
  mkdir -p "$outdir"
  magick "$img" -resize 800x "$outdir/$(basename "$img")"
done

Batch with Different Sizes

# Generate multiple sizes
for size in 320 640 1024 1920; do
  mkdir -p "output/${size}w"
  for img in *.jpg; do
    magick "$img" -resize ${size}x -quality 85 "output/${size}w/$img"
  done
done

# Parallel version
for size in 320 640 1024 1920; do
  mkdir -p "output/${size}w"
  parallel magick {} -resize ${size}x -quality 85 "output/${size}w/{}" ::: *.jpg
done

Responsive Image Set

# Create responsive image set with srcset
mkdir -p responsive
for img in *.jpg; do
  base="${img%.jpg}"
  for width in 320 640 1024 1920; do
    magick "$img" -resize ${width}x -quality 85 \
      "responsive/${base}-${width}w.jpg"
  done
done

Watermark Batch

# Add watermark to all images
for img in *.jpg; do
  magick "$img" watermark.png \
    -gravity southeast -geometry +10+10 \
    -composite "watermarked_$img"
done

# Different watermark positions for portrait vs landscape
for img in *.jpg; do
  width=$(identify -format "%w" "$img")
  height=$(identify -format "%h" "$img")

  if [ $width -gt $height ]; then
    # Landscape
    magick "$img" watermark.png -gravity southeast -composite "marked_$img"
  else
    # Portrait
    magick "$img" watermark.png -gravity south -composite "marked_$img"
  fi
done

Error Handling

Check Before Processing

# Verify image before processing
for img in *.jpg; do
  if identify "$img" > /dev/null 2>&1; then
    magick "$img" -resize 800x "processed_$img"
  else
    echo "Skipping corrupt image: $img"
  fi
done

Log Processing

# Log successful and failed operations
log_file="batch_process.log"
error_log="errors.log"

for img in *.jpg; do
  if magick "$img" -resize 800x "output/$img" 2>> "$error_log"; then
    echo "$(date): Processed $img" >> "$log_file"
  else
    echo "$(date): Failed $img" >> "$error_log"
  fi
done

Dry Run Mode

# Test without modifying files
dry_run=true

for img in *.jpg; do
  cmd="magick $img -resize 800x processed_$img"
  if [ "$dry_run" = true ]; then
    echo "Would run: $cmd"
  else
    eval $cmd
  fi
done

Optimization Workflows

Web Publishing Pipeline

# Complete web optimization workflow
mkdir -p web/{original,optimized,thumbnails}

# Copy originals
cp *.jpg web/original/

# Create optimized versions
mogrify -path web/optimized \
  -resize 1920x1080\> \
  -quality 85 \
  -strip \
  -interlace Plane \
  web/original/*.jpg

# Create thumbnails
mogrify -path web/thumbnails \
  -thumbnail 300x300 \
  -quality 80 \
  -strip \
  web/original/*.jpg

Archive to Web Conversion

# Convert high-res archives to web formats
for img in archives/*.jpg; do
  base=$(basename "$img" .jpg)

  # Full size web version
  magick "$img" -resize 2048x2048\> -quality 90 -strip "web/${base}.jpg"

  # Thumbnail
  magick "$img" -thumbnail 400x400 -quality 85 "web/${base}_thumb.jpg"

  # WebP version
  magick "$img" -resize 2048x2048\> -quality 85 "web/${base}.webp"
done

Print to Web Workflow

# Convert print-ready images to web
for img in print/*.tif; do
  base=$(basename "$img" .tif)

  # Convert colorspace and optimize
  magick "$img" \
    -colorspace sRGB \
    -resize 2000x2000\> \
    -quality 90 \
    -strip \
    -interlace Plane \
    "web/${base}.jpg"
done

Batch Reporting

Generate Report

# Create processing report
report="batch_report.txt"
echo "Batch Processing Report - $(date)" > "$report"
echo "================================" >> "$report"

total=0
success=0
failed=0

for img in *.jpg; do
  ((total++))
  if magick "$img" -resize 800x "output/$img" 2>/dev/null; then
    ((success++))
    echo "✓ $img" >> "$report"
  else
    ((failed++))
    echo "✗ $img" >> "$report"
  fi
done

echo "" >> "$report"
echo "Total: $total, Success: $success, Failed: $failed" >> "$report"

Image Inventory

# Create inventory of images
inventory="image_inventory.csv"
echo "Filename,Width,Height,Format,Size,ColorSpace" > "$inventory"

for img in *.{jpg,png,gif}; do
  [ -f "$img" ] || continue
  info=$(identify -format "%f,%w,%h,%m,%b,%[colorspace]" "$img")
  echo "$info" >> "$inventory"
done

Performance Tips

Optimize Loop Performance

# Bad: Launch mogrify for each file
for img in *.jpg; do
  mogrify -resize 800x "$img"
done

# Good: Process all files in one mogrify call
mogrify -resize 800x *.jpg

# Best: Use parallel processing for complex operations
parallel magick {} -resize 800x -quality 85 processed_{} ::: *.jpg

Memory Management

# Limit memory for batch processing
for img in *.jpg; do
  magick -limit memory 2GB -limit map 4GB \
    "$img" -resize 50% "output/$img"
done

Progress Tracking

# Show progress for long batch operations
total=$(ls *.jpg | wc -l)
current=0

for img in *.jpg; do
  ((current++))
  echo "Processing $current/$total: $img"
  magick "$img" -resize 800x "output/$img"
done

Automation Scripts

Complete Bash Script

#!/bin/bash

# Configuration
INPUT_DIR="./input"
OUTPUT_DIR="./output"
QUALITY=85
MAX_WIDTH=1920
THUMBNAIL_SIZE=300

# Create output directories
mkdir -p "$OUTPUT_DIR"/{full,thumbnails}

# Process images
echo "Processing images..."
for img in "$INPUT_DIR"/*.{jpg,jpeg,png}; do
  [ -f "$img" ] || continue

  filename=$(basename "$img")
  base="${filename%.*}"

  # Full size
  magick "$img" \
    -resize ${MAX_WIDTH}x\> \
    -quality $QUALITY \
    -strip \
    "$OUTPUT_DIR/full/${base}.jpg"

  # Thumbnail
  magick "$img" \
    -thumbnail ${THUMBNAIL_SIZE}x${THUMBNAIL_SIZE} \
    -quality 80 \
    -strip \
    "$OUTPUT_DIR/thumbnails/${base}_thumb.jpg"

  echo "✓ $filename"
done

echo "Done!"

Python Batch Script

#!/usr/bin/env python3
import os
import subprocess
from pathlib import Path

INPUT_DIR = Path("./input")
OUTPUT_DIR = Path("./output")
SIZES = [320, 640, 1024, 1920]

# Create output directories
for size in SIZES:
    (OUTPUT_DIR / f"{size}w").mkdir(parents=True, exist_ok=True)

# Process images
for img in INPUT_DIR.glob("*.jpg"):
    for size in SIZES:
        output = OUTPUT_DIR / f"{size}w" / img.name
        subprocess.run([
            "magick", str(img),
            "-resize", f"{size}x",
            "-quality", "85",
            "-strip",
            str(output)
        ])
        print(f"✓ {img.name} -> {size}w")

Common Batch Recipes

Social Media Sizes

# Generate social media image sizes
for img in *.jpg; do
  base="${img%.jpg}"

  # Instagram square (1080×1080)
  magick "$img" -resize 1080x1080^ -gravity center -extent 1080x1080 "${base}_ig_square.jpg"

  # Instagram portrait (1080×1350)
  magick "$img" -resize 1080x1350^ -gravity center -extent 1080x1350 "${base}_ig_portrait.jpg"

  # Facebook post (1200×630)
  magick "$img" -resize 1200x630^ -gravity center -extent 1200x630 "${base}_fb_post.jpg"

  # Twitter post (1200×675)
  magick "$img" -resize 1200x675^ -gravity center -extent 1200x675 "${base}_tw_post.jpg"
done

Email Newsletter Images

# Optimize images for email
mogrify -path ./email \
  -resize 600x\> \
  -quality 75 \
  -strip \
  -interlace Plane \
  *.jpg

Backup and Archive

# Create web versions and keep originals
mkdir -p {originals,web}

# Move originals
mv *.jpg originals/

# Create optimized copies
for img in originals/*.jpg; do
  base=$(basename "$img")
  magick "$img" -resize 2000x2000\> -quality 85 -strip "web/$base"
done

ImageMagick Image Editing

Complete guide to format conversion, resizing, effects, transformations, and composition.

Format Conversion

Basic Conversion

Convert between image formats.

# PNG to JPEG
magick input.png output.jpg

# JPEG to WebP
magick input.jpg output.webp

# Multiple outputs simultaneously
magick input.png output.jpg output.webp output.gif

# Convert with quality setting
magick input.png -quality 85 output.jpg

Quality Settings

JPEG Quality (0-100):

• 95-100: Archival, minimal compression
• 85-94: High quality, web publishing
• 75-84: Medium quality, web optimized
• 60-74: Lower quality, smaller files
• Below 60: Visible artifacts

# High quality
magick input.png -quality 95 output.jpg

# Web optimized (recommended)
magick input.png -quality 85 -strip output.jpg

# Smaller file size
magick input.png -quality 75 -sampling-factor 4:2:0 -strip output.jpg

PNG Quality (0-9 = compression level):

# Maximum compression (slower)
magick input.jpg -quality 95 output.png

# Faster compression
magick input.jpg -quality 75 output.png

WebP Quality:

# Lossy with quality
magick input.jpg -quality 80 output.webp

# Lossless
magick input.png -define webp:lossless=true output.webp

Progressive & Optimization

# Progressive JPEG (better web loading)
magick input.png -quality 85 -interlace Plane output.jpg

# Strip metadata (reduce file size)
magick input.jpg -strip output.jpg

# Combined optimization
magick input.png -quality 85 -interlace Plane -strip output.jpg

Resizing Operations

Basic Resize

Maintain aspect ratio.

# Fit within 800×600
magick input.jpg -resize 800x600 output.jpg

# Resize to specific width (auto height)
magick input.jpg -resize 800x output.jpg

# Resize to specific height (auto width)
magick input.jpg -resize x600 output.jpg

# Scale by percentage
magick input.jpg -resize 50% output.jpg

Advanced Resize

# Resize only if larger (shrink only)
magick input.jpg -resize 800x600\> output.jpg

# Resize only if smaller (enlarge only)
magick input.jpg -resize 800x600\< output.jpg

# Force exact dimensions (ignore aspect ratio)
magick input.jpg -resize 800x600! output.jpg

# Fill dimensions (may crop)
magick input.jpg -resize 800x600^ output.jpg

# Minimum dimensions
magick input.jpg -resize 800x600^ output.jpg

Resize Algorithms

# High quality (Lanczos)
magick input.jpg -filter Lanczos -resize 50% output.jpg

# Fast resize (Box)
magick input.jpg -filter Box -resize 50% output.jpg

# Mitchel filter (good balance)
magick input.jpg -filter Mitchell -resize 50% output.jpg

Filter comparison:

• Lanczos - Highest quality, slower
• Mitchell - Good quality, fast
• Catrom - Sharp, good for downscaling
• Box - Fastest, acceptable quality
• Cubic - Smooth results

Cropping

Basic Crop

Extract region from image.

# Crop width×height+x+y
magick input.jpg -crop 400x400+100+100 output.jpg

# Remove virtual canvas after crop
magick input.jpg -crop 400x400+100+100 +repage output.jpg

# Crop from center
magick input.jpg -gravity center -crop 400x400+0+0 output.jpg

# Crop to aspect ratio
magick input.jpg -gravity center -crop 16:9 +repage output.jpg

Smart Crop

Content-aware cropping.

# Trim transparent/same-color borders
magick input.png -trim +repage output.png

# Trim with fuzz tolerance
magick input.jpg -fuzz 10% -trim +repage output.jpg

Thumbnail Generation

Create square thumbnails from any aspect ratio.

# Resize and crop to square
magick input.jpg -resize 200x200^ -gravity center -extent 200x200 thumb.jpg

# Alternative method
magick input.jpg -thumbnail 200x200^ -gravity center -crop 200x200+0+0 +repage thumb.jpg

# With background (no crop)
magick input.jpg -resize 200x200 -background white -gravity center -extent 200x200 thumb.jpg

Effects & Filters

Blur Effects

# Standard blur (radius 0 = auto)
magick input.jpg -blur 0x8 output.jpg

# Gaussian blur (radius×sigma)
magick input.jpg -gaussian-blur 5x3 output.jpg

# Motion blur (angle)
magick input.jpg -motion-blur 0x20+45 output.jpg

# Radial blur
magick input.jpg -radial-blur 10 output.jpg

Sharpen

# Basic sharpen
magick input.jpg -sharpen 0x1 output.jpg

# Stronger sharpen
magick input.jpg -sharpen 0x3 output.jpg

# Unsharp mask (advanced)
magick input.jpg -unsharp 0x1 output.jpg

Color Effects

# Grayscale
magick input.jpg -colorspace Gray output.jpg

# Sepia tone
magick input.jpg -sepia-tone 80% output.jpg

# Negate (invert colors)
magick input.jpg -negate output.jpg

# Posterize (reduce colors)
magick input.jpg -posterize 8 output.jpg

# Solarize
magick input.jpg -solarize 50% output.jpg

Artistic Effects

# Edge detection
magick input.jpg -edge 3 output.jpg

# Emboss
magick input.jpg -emboss 2 output.jpg

# Oil painting
magick input.jpg -paint 4 output.jpg

# Charcoal drawing
magick input.jpg -charcoal 2 output.jpg

# Sketch
magick input.jpg -sketch 0x20+120 output.jpg

# Swirl
magick input.jpg -swirl 90 output.jpg

Adjustments

Brightness & Contrast

# Increase brightness
magick input.jpg -brightness-contrast 10x0 output.jpg

# Increase contrast
magick input.jpg -brightness-contrast 0x20 output.jpg

# Both
magick input.jpg -brightness-contrast 10x20 output.jpg

# Negative values to decrease
magick input.jpg -brightness-contrast -10x-10 output.jpg

Color Adjustments

# Adjust saturation (HSL modulation)
# Format: brightness,saturation,hue
magick input.jpg -modulate 100,150,100 output.jpg

# Adjust hue
magick input.jpg -modulate 100,100,120 output.jpg

# Combined adjustments
magick input.jpg -modulate 105,120,100 output.jpg

# Adjust specific color channels
magick input.jpg -channel Red -evaluate multiply 1.2 output.jpg

Auto Corrections

# Auto level (normalize contrast)
magick input.jpg -auto-level output.jpg

# Auto gamma correction
magick input.jpg -auto-gamma output.jpg

# Normalize (stretch histogram)
magick input.jpg -normalize output.jpg

# Enhance (digital enhancement)
magick input.jpg -enhance output.jpg

# Equalize (histogram equalization)
magick input.jpg -equalize output.jpg

Transformations

Rotation

# Rotate 90° clockwise
magick input.jpg -rotate 90 output.jpg

# Rotate 180°
magick input.jpg -rotate 180 output.jpg

# Rotate counter-clockwise
magick input.jpg -rotate -90 output.jpg

# Rotate with background
magick input.jpg -background white -rotate 45 output.jpg

# Auto-orient based on EXIF
magick input.jpg -auto-orient output.jpg

Flip & Mirror

# Flip vertically
magick input.jpg -flip output.jpg

# Flip horizontally (mirror)
magick input.jpg -flop output.jpg

# Both
magick input.jpg -flip -flop output.jpg

Borders & Frames

Simple Borders

# Add 10px black border
magick input.jpg -border 10x10 output.jpg

# Colored border
magick input.jpg -bordercolor red -border 10x10 output.jpg

# Different width/height
magick input.jpg -bordercolor blue -border 20x10 output.jpg

Advanced Frames

# Raised frame
magick input.jpg -mattecolor gray -frame 10x10+5+5 output.jpg

# Shadow effect
magick input.jpg \
  \( +clone -background black -shadow 80x3+5+5 \) \
  +swap -background white -layers merge +repage \
  output.jpg

# Rounded corners
magick input.jpg \
  \( +clone -threshold -1 -draw "fill black polygon 0,0 0,15 15,0 fill white circle 15,15 15,0" \
  \( +clone -flip \) -compose multiply -composite \
  \( +clone -flop \) -compose multiply -composite \
  \) -alpha off -compose copy_opacity -composite \
  output.png

Text & Annotations

Basic Text

# Simple text overlay
magick input.jpg -pointsize 30 -fill white -annotate +10+30 "Hello" output.jpg

# Positioned text
magick input.jpg -gravity south -pointsize 20 -fill white \
  -annotate +0+10 "Copyright 2025" output.jpg

# Text with background
magick input.jpg -gravity center -pointsize 40 -fill white \
  -undercolor black -annotate +0+0 "Watermark" output.jpg

Advanced Text

# Semi-transparent watermark
magick input.jpg \
  \( -background none -fill "rgba(255,255,255,0.5)" \
  -pointsize 50 label:"DRAFT" \) \
  -gravity center -compose over -composite \
  output.jpg

# Text with stroke
magick input.jpg -gravity center \
  -stroke black -strokewidth 2 -fill white \
  -pointsize 60 -annotate +0+0 "Title" \
  output.jpg

# Custom font
magick input.jpg -font Arial-Bold -pointsize 40 \
  -gravity center -fill white -annotate +0+0 "Text" \
  output.jpg

Image Composition

Overlay Images

# Basic overlay (top-left)
magick input.jpg overlay.png -composite output.jpg

# Position with gravity
magick input.jpg watermark.png -gravity southeast -composite output.jpg

# Position with offset
magick input.jpg watermark.png -gravity southeast \
  -geometry +10+10 -composite output.jpg

# Center overlay
magick input.jpg logo.png -gravity center -composite output.jpg

Composite Modes

# Over (default)
magick input.jpg overlay.png -compose over -composite output.jpg

# Multiply
magick input.jpg texture.png -compose multiply -composite output.jpg

# Screen
magick input.jpg light.png -compose screen -composite output.jpg

# Overlay blend mode
magick input.jpg pattern.png -compose overlay -composite output.jpg

Side-by-Side

# Horizontal append
magick image1.jpg image2.jpg +append output.jpg

# Vertical append
magick image1.jpg image2.jpg -append output.jpg

# With spacing
magick image1.jpg image2.jpg -gravity center \
  -background white -splice 10x0 +append output.jpg

Transparency

Create Transparency

# Make color transparent
magick input.jpg -transparent white output.png

# Make similar colors transparent (with fuzz)
magick input.jpg -fuzz 10% -transparent white output.png

# Alpha channel operations
magick input.png -alpha set -channel A -evaluate multiply 0.5 +channel output.png

Remove Transparency

# Flatten with white background
magick input.png -background white -flatten output.jpg

# Flatten with custom color
magick input.png -background "#ff0000" -flatten output.jpg

Advanced Techniques

Vignette Effect

# Default vignette
magick input.jpg -vignette 0x20 output.jpg

# Custom vignette
magick input.jpg -background black -vignette 0x25+10+10 output.jpg

Depth of Field Blur

# Radial blur from center
magick input.jpg \
  \( +clone -blur 0x8 \) \
  \( +clone -fill white -colorize 100 \
  -fill black -draw "circle %[fx:w/2],%[fx:h/2] %[fx:w/2],%[fx:h/4]" \
  -blur 0x20 \) \
  -composite output.jpg

HDR Effect

magick input.jpg \
  \( +clone -colorspace gray \) \
  \( -clone 0 -auto-level -modulate 100,150,100 \) \
  -delete 0 -compose overlay -composite \
  output.jpg

Tilt-Shift Effect

magick input.jpg \
  \( +clone -sparse-color Barycentric '0,%[fx:h*0.3] gray0 0,%[fx:h*0.5] white 0,%[fx:h*0.7] gray0' \) \
  \( +clone -blur 0x20 \) \
  -compose blend -define compose:args=100 -composite \
  output.jpg

Color Management

Color Profiles

# Strip color profile
magick input.jpg -strip output.jpg

# Assign color profile
magick input.jpg -profile sRGB.icc output.jpg

# Convert between profiles
magick input.jpg -profile AdobeRGB.icc -profile sRGB.icc output.jpg

Color Space Conversion

# Convert to sRGB
magick input.jpg -colorspace sRGB output.jpg

# Convert to CMYK (print)
magick input.jpg -colorspace CMYK output.tif

# Convert to LAB
magick input.jpg -colorspace LAB output.jpg

Performance Optimization

Memory Management

# Limit memory usage
magick -limit memory 2GB -limit map 4GB input.jpg -resize 50% output.jpg

# Set thread count
magick -limit thread 4 input.jpg -resize 50% output.jpg

# Streaming for large files
magick -define stream:buffer-size=0 huge.jpg -resize 50% output.jpg

Quality vs Size

# Maximum quality (large file)
magick input.jpg -quality 95 output.jpg

# Balanced (recommended)
magick input.jpg -quality 85 -strip output.jpg

# Smaller file (acceptable quality)
magick input.jpg -quality 70 -sampling-factor 4:2:0 -strip output.jpg

# Progressive JPEG
magick input.jpg -quality 85 -interlace Plane -strip output.jpg

Common Recipes

Avatar/Profile Picture

# Square thumbnail
magick input.jpg -resize 200x200^ -gravity center -extent 200x200 avatar.jpg

# Circular avatar (PNG)
magick input.jpg -resize 200x200^ -gravity center -extent 200x200 \
  \( +clone -threshold -1 -negate -fill white -draw "circle 100,100 100,0" \) \
  -alpha off -compose copy_opacity -composite avatar.png

Responsive Images

# Generate multiple sizes
for size in 320 640 1024 1920; do
  magick input.jpg -resize ${size}x -quality 85 -strip "output-${size}w.jpg"
done

Photo Enhancement

# Auto-enhance workflow
magick input.jpg \
  -auto-level \
  -unsharp 0x1 \
  -brightness-contrast 5x10 \
  -modulate 100,110,100 \
  -quality 90 -strip \
  output.jpg

RMBG - Background Removal CLI

Local AI-powered background removal tool. Repository: https://github.com/mrgoonie/rmbg

Installation

npm install -g rmbg-cli
# or
pnpm install -g rmbg-cli

Usage

# Basic usage (uses modnet model)
rmbg input.jpg

# Specify output path
rmbg input.jpg -o output.png

# Choose model
rmbg input.jpg -m briaai -o high-quality.png

# Set max resolution
rmbg image.jpg -r 4096 -o image-4k.png

CLI Options

• -o, --output <path> - Output path (default: input-no-bg.png)
• -m, --model <model> - Model name (default: modnet)
• -r, --max-resolution <n> - Max resolution in pixels (default: 2048)

Available Models

Examples

# Fast processing
rmbg photo.jpg -m u2netp -o fast-result.png

# High quality output
rmbg photo.jpg -m briaai -r 4096 -o hq-result.png

# Batch processing
for img in *.jpg; do
  rmbg "$img" -m u2netp -o "output/${img%.jpg}.png"
done

Notes

• Models download automatically on first use (~4-170MB depending on model)
• Cache location: macOS: /var/folders/.../T/rmbg-cache/ | Linux: /tmp/rmbg-cache/ | Windows: %TEMP%\rmbg-cache\
• Supported formats: JPEG, PNG, WebP
• Max file size: 50MB

Media Processing Troubleshooting

FFmpeg Issues

Unknown Encoder Error

# Check available encoders
ffmpeg -encoders | grep h264

# Install codec libraries (Ubuntu/Debian)
sudo apt-get install libx264-dev libx265-dev libvpx-dev

Memory Errors

# Limit thread usage
ffmpeg -threads 4 input.mp4 output.mp4

# Process in segments for large files
ffmpeg -i large.mp4 -ss 0 -t 600 segment1.mp4
ffmpeg -i large.mp4 -ss 600 -t 600 segment2.mp4

Slow Encoding

# Use faster preset (trades compression for speed)
ffmpeg -i input.mp4 -c:v libx264 -preset ultrafast output.mp4

# Use hardware acceleration
ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc output.mp4

ImageMagick Issues

"Not Authorized" Error

# Edit policy file
sudo nano /etc/ImageMagick-7/policy.xml

# Change from:
# <policy domain="coder" rights="none" pattern="PDF" />

# To:
# <policy domain="coder" rights="read|write" pattern="PDF" />

Memory Limit Errors

# Increase memory limits
magick -limit memory 2GB -limit map 4GB input.jpg output.jpg

# Process in batches for large sets
ls *.jpg | xargs -n 10 -P 4 mogrify -resize 800x

Slow Batch Processing

# Use parallel processing with GNU Parallel
ls *.jpg | parallel -j 4 magick {} -resize 800x resized-{}

# Or use mogrify for in-place edits (faster)
mogrify -resize 800x *.jpg

RMBG Issues

Model Download Failures

# Check network connectivity
curl https://unpkg.com/@rmbg/model-modnet/modnet-256.onnx

# Use custom cache directory
RMBG_CACHE_DIR=/tmp/rmbg-cache rmbg input.jpg

# Clear cache and retry
rm -rf /tmp/rmbg-cache
rmbg input.jpg

Out of Memory

# Use smaller model
rmbg input.jpg -m u2netp -o output.png

# Reduce resolution
rmbg input.jpg -r 1024 -o output.png

Slow Processing

# Use fastest model
rmbg input.jpg -m u2netp -o output.png

# Process smaller resolution
rmbg input.jpg -r 1024 -o output.png

Performance Tips

1. Use CRF for quality control - Better than bitrate for video encoding 2. Copy streams when possible - Avoid re-encoding with -c copy 3. Hardware acceleration - GPU encoding 5-10x faster than CPU 4. Appropriate presets - Balance speed vs compression (fast, medium, slow) 5. Batch with mogrify - In-place image processing faster than individual commands 6. Strip metadata - Reduce file size with -strip flag 7. Progressive JPEG - Better web loading with -interlace Plane 8. Test on samples - Verify settings before processing large batches 9. Parallel processing - Use GNU Parallel for multiple files 10. Limit memory - Prevent crashes on large batches with -limit flags

Media Processing Scripts

Helper scripts for common media processing tasks.

Background Removal Scripts

remove-background.sh

Remove background from a single image using RMBG CLI.

# Basic usage
./remove-background.sh photo.jpg

# With specific model
./remove-background.sh photo.jpg briaai

# With custom output and resolution
./remove-background.sh photo.jpg briaai output.png 4096

Arguments:

• input - Input image file (required)
• model - Model name: u2netp, modnet, briaai, isnet-anime, silueta, u2net-cloth (default: modnet)
• output - Output file path (default: auto-generated)
• resolution - Max resolution in pixels (default: 2048)

batch-remove-background.sh

Remove backgrounds from all images in a directory.

# Basic usage
./batch-remove-background.sh ./photos

# With custom output directory
./batch-remove-background.sh ./photos ./output

# With specific model and resolution
./batch-remove-background.sh ./photos ./output briaai 4096

Arguments:

• input_dir - Input directory with images (required)
• output_dir - Output directory (default: input_dir/no-bg)
• model - Model name (default: modnet)
• resolution - Max resolution in pixels (default: 2048)

remove-bg-node.js

Node.js script for background removal with progress tracking.

# Basic usage
node remove-bg-node.js photo.jpg

# With options
node remove-bg-node.js photo.jpg -m briaai -o output.png -r 4096 -p

Options:

• -o, --output <path> - Output file path
• -m, --model <name> - Model: briaai, modnet, u2netp
• -r, --resolution <n> - Max resolution
• -p, --progress - Show progress

Image Processing Scripts

batch_resize.py

Batch resize images with various options.

python batch_resize.py -i ./input -o ./output -w 800 -h 600

Video Processing Scripts

video_optimize.py

Optimize videos for web with quality and size optimization.

python video_optimize.py -i input.mp4 -o output.mp4 --preset slow --crf 23

media_convert.py

Convert media files between different formats.

python media_convert.py -i input.mkv -o output.mp4 --codec h264

Requirements

Shell Scripts

• Bash (macOS, Linux)
• rmbg-cli: npm install -g rmbg-cli
• FFmpeg: brew install ffmpeg or apt-get install ffmpeg
• ImageMagick: brew install imagemagick or apt-get install imagemagick

Node.js Scripts

• Node.js 14+
• Dependencies: npm install rmbg

Python Scripts

• Python 3.7+
• Dependencies: pip install -r requirements.txt

Testing

Run tests:

cd tests
bash test_all.sh