Settings + encoder side of HDR video export (frame data still SDR until pt 2):
- core: HdrExportMode {Sdr (default), Pq, Hlg} on VideoExportSettings (serde
default), with transfer-name helpers.
- setup_video_encoder takes the mode: HDR → YUV420P10LE, BT.2020 NCL matrix,
limited range, color_primaries=bt2020, color_trc=smpte2084/arib-std-b67,
profile=main10. SDR path unchanged (8-bit full-range BT.709).
- run_video_encoder forces HEVC when HDR is selected (the only 10-bit codec wired
up). encode_frame is parameterized by pixel format and now copies planes
row-by-row honoring stride (10-bit / non-aligned widths can have row padding).
Dormant: no UI exposes the mode yet and the frame data is still 8-bit SDR, so
selecting HDR is not yet wired. The render→PQ/HLG 10-bit frame path is pt 2.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>