media-processing_skill

Overview

This skill provides practical command-line media processing using FFmpeg for video/audio and ImageMagick for images. It covers format conversion, codec encoding (H.264/H.265/VP9/AV1), thumbnails, watermarks, streaming manifests (HLS/DASH), and batch operations. The goal is reliable, repeatable workflows for optimization, streaming, and automated media tasks. Examples and tips focus on real-world commands and performance considerations.

How this skill works

I use FFmpeg to inspect, transcode, trim, filter, and package video/audio, leveraging ffprobe for metadata and optional hardware acceleration (NVENC/QSV). ImageMagick handles image conversions, resizing, composition, and batch editing with mogrify. Common actions include converting formats, extracting audio, generating thumbnails, overlaying watermarks, creating HLS/DASH playlists, and running multi-file pipelines. Commands are presented for fast iteration and production-ready outputs.

When to use it

• Convert video/audio to web-friendly formats (MP4/H.264, WebM/VP9, AV1) for delivery.
• Extract or re-encode audio tracks and generate standalone audio files.
• Generate thumbnails, contact sheets, or preview images for media catalogs.
• Create HLS or DASH manifests for adaptive streaming and VOD delivery.
• Batch-resize, optimize, or watermark large image sets before publishing.
• Trim, concatenate, or transcode clips for editing or archive workflows.

Best practices

• Prefer CRF-based encoding for quality control instead of fixed bitrate where possible.
• Use -c copy to avoid re-encoding when only container changes are needed.
• Test settings on short samples before running large batches to save time.
• Enable hardware acceleration (NVENC/QSV) on supported machines for speed.
• Strip unnecessary metadata and use progressive/interlaced options for web performance.
• Run parallel jobs (GNU Parallel) for large batches and limit threads to avoid memory spikes.

Example use cases

• Convert a directory of raw recordings to H.264 MP4 with consistent bitrate and faststart for web playback.
• Extract high-quality AAC audio from lectures and produce MP3 versions for podcast distribution.
• Generate 4 responsive image sizes and square thumbnails for a content management system.
• Create HLS VOD playlists with 6-second segments and multiple bitrate renditions for adaptive streaming.
• Overlay a PNG logo watermark on video corners and batch-process a video library.
• Produce an optimized GIF from a video segment using palette generation and frame-rate control.