Generated clips (nothing binary committed) go through extractAudio: a video's audio reaches the server as 16 kHz mono WAV, a 12-second recording is uploaded in two ranges under a small limit, and a video without sound is refused before anything is uploaded. Skipped where ffmpeg is missing, which may include CI runners. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01MRtGG9ARfqqhma3t85Ro2u