[davidvanleeuwen]

✨ What changes

H.264 sources with 10-bit pixels or 4:2:2/4:4:4 chroma can produce renditions that browser MediaSource decoders reject. Normalize browser-facing output to 8-bit 4:2:0 and only reuse inspected H.264 sources with compatible profiles and pixel formats.

• Normalize local H.264 encoding, including dense-keyframe clips, and validate outputs before publication.
• Transcode inline sources in auto mode; retain explicit copy mode for fixtures and custom flows.
• Add real-codec regression coverage for the CPU booster and local encoders, with the booster check running in CI.
• Retry interrupted media-image FFmpeg downloads over HTTP/1.1, retaining the pinned version and checksum checks.

👀 Behavior

Synthetic source	Result
10-bit 4:2:0, 10-bit 4:2:2, 8/10-bit 4:4:4	8-bit 4:2:0 H.264
Incompatible or unknown source format	Transcoded instead of copied

🔎 Additional checks

Real FFmpeg conversion and output-validation checks passed with the required media sandbox enabled. The Alpine download completed with the expected pinned SHA-256. Custom flows relying on implicit inline copying must select copy explicitly.