Transcodes were uncapped (ffmpeg maxBitrate=0 + preset=ultrafast +
targetResolution=original) -> 77-264 Mbps 4K H.264 files. Mobile playback
streams that copy off the shared 7200rpm sdc pool over inter-VLAN NFS; a single
stream needs ~10-13.5 MB/s and stuttered for every client, local and remote.
Fix (DB system-config, applied via API): maxBitrate=20000k, preset=medium,
transcode=bitrate. 4K resolution preserved; originals never modified. Existing
oversized transcodes regenerated by deleting their asset_file encoded_video rows
+ videoConversion force=false (concurrency 1).
Document config + add runbook docs/runbooks/immich-transcode-bitrate.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
