Audit follow-up to the muxl-appsink sync fix: swept every appsink in the tree for clock sync. - thumbnailFromMP4 (thumbnail.go): the flat-MP4 thumbnail pipeline was the only consumer-path appsink still defaulting to sync=true. In practice videorate re-stamps the selected frame to PTS 0 so it usually rendered immediately, but there's no reason to leave it on the clock — and its twin Thumbnail() already sets sync=false. - SelfTest (gstreamer.go): untimestamped buffers so sync never actually waited; set sync=false for consistency so the tree greps clean. - sp whip (cmd/whip.go): the ONE appsink pair where sync=true is load-bearing — the client plays a file over WHIP as a live stream and the appsink clock wait is the only realtime pacing (pion WriteSample pushes immediately). Made sync=true explicit with a comment so a future sweep doesn't "fix" it. Already sync=false (no change): packetize, media_data_parser, segment_conv, transcode, vod_pipeline, segmenter (via sink-added), Thumbnail, muxl_segment. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>