Ffmpeg Detect

Context: $ARGUMENTS

Detect-and-act filters in ffmpeg are read-only analysis passes. They write findings to stderr (and/or frame metadata under lavfi.*), never modify the file, and are designed to be parsed by a script that then issues a second ffmpeg call with real parameters.

Quick start

• Autocrop black bars: → Step 1 (cropdetect) → Step 3 (apply crop=W:H:X:Y)
• Trim silences: → Step 1 (silencedetect) → Step 3 (cut with -ss/-to pairs)
• Find black frames / scene cuts: → Step 1 (blackdetect / scdet) → Step 3 (split with concat demuxer)
• Check if interlaced: → Step 1 (idet) → Step 3 (decide on yadif/bwdif)
• Broadcast QC: → Step 1 (signalstats) → Step 3 (flag out-of-range YMIN/YMAX/SATMAX)
• Read embedded captions / timecode: → readeia608, readvitc
• Pre-loudnorm audio stats: → volumedetect, astats (use loudnorm from ffmpeg-audio-filter for true LUFS)

When to use