NVENC rejects -g 1 ("GopLength > numBFrames+1" at InitializeEncoder), so
true all-intra is achieved with -bf 0 -forced-idr 1 -g 600 plus
-force_key_frames expr:1 (forces an IDR on every frame). ffprobe confirms
all frames are pict_type=I. Container is fragmented MOV; MXF muxing of HEVC
fails on this ffmpeg build ("Operation not permitted").
Validated end-to-end via direct ffmpeg on zampp2/L4:
hevc, Main 10, 1920x1080, yuv420p10le, ptypes=[IIIIII...]
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Zac Gaetano
9210b41589