Ffmpeg Audio Spatial

Context: $ARGUMENTS

Quick start

• 5.1/7.1 → binaural headphones: Step 1 (probe layout) → Step 2 (pick headphone or sofalizer) → Step 3 (build filter, ClockWise channel order)
• Stereo → 5.1 upmix: Step 1 (probe) → Step 2 (pick surround) → Step 3 (chl_out=5.1)
• Stereo widen / crossfeed / earwax: Step 2 (pick stereo FX) → Step 3 (one-liner -af)
• Split / remap / join channels: Step 2 (pick channelsplit / pan / amerge) → Step 3 (build graph)

When to use

• You need a binaural headphone downmix from a 5.1/7.1 film or game mix.
• You are given a stereo master and asked to "make it wider," "add space," "reduce ping-pong fatigue on earbuds," or "trick a stereo file into 5.1."
• You need to split a multichannel master into one-mono-per-channel files (stem prep).
• You need to remap, reroute, or merge separate mono tracks into a laid-out multichannel bus.

Step 1 — Identify the channel layout