h265d: HDR dynamic metadata (HDR10+/HDR Vivid) SEI is only attached to the first frame

[DXICM]

When decoding HEVC streams carrying per-frame HDR dynamic metadata SEI
(SMPTE ST 2094-40 / HDR10+ or CUVA HDR Vivid), mpp_frame_get_hdr_dynamic_meta()
only returns data for the first decoded frame; subsequent frames that carry the
same SEI report no dynamic metadata.

Evidence

1. mpi_dec_test on an HDR Vivid HEVC stream whose SEI repeats in multiple AUs:
   with h265d_debug=8704 the hdr_meta log line only appears for poc 0, even
   though the SEI is present in later AUs as well.
2. Comparison with software decoding (FFmpeg hevc decoder): the dynamic HDR
   side data is present on N frames (e.g. 6) while hevc_rkmpp (via FFmpeg)
   exports it on only 1 frame for the same file.
3. Streams that repeat the SEI in every AU (e.g. typical HDR10+ UHD Blu-ray
   rips) are unaffected because frame 0 still gets the metadata and every frame
   carries it — but the parser appears to latch the SEI once instead of
   refreshing it per AU.

Expected behavior

The parser should attach the HDR dynamic metadata SEI carried by each AU to the
corresponding MppFrame (as it already does for the first AU), so per-frame
dynamic tone-mapping works.

Environment

• MPP develop branch, v1.0.12 (8f922ed)
• RK3576 and RK3588
• Kernel 5.10 / 6.1 (both observed)

Suggested fix area

mpp/codec/dec/h265/h265d_sei.c (the dynamic-meta SEI callback stores into a
once-only context) / frame-export path in mpp/codec/dec/h265 where
KEY_HDR_INFO / hdr_dynamic_meta is attached to MppFrame.

[FumasterLin]

Please upload a stream to reproduce

[DXICM]

Thanks for the quick response. I have uploaded the repro streams and a comparison script to https://github.com/DXICM/mpp-hdr-sei-repro :

Stream	Content	rkmpp vs software decoder
hdr10plus_hevc.h265	HDR10+ (ST 2094-40), 6 frames, SEI in every AU	hw=1 sw=6
hdr_vivid_hevc_repeat.h265	CUVA HDR Vivid, 6 frames, SEI in every AU	hw=1 sw=6
hdr_vivid_hevc.h265	CUVA HDR Vivid, 1 frame / 1 SEI (control)	hw=1 sw=1

Both primary streams are freely usable (ToS excerpt, CC-BY; fate-suite vivid sample), no licensed content.

Reproduction with native mpi_dec_test (MPP develop v1.0.12, 8f922ed):

h265d_debug=8704 ./mpi_dec_test -i hdr10plus_hevc.h265 -t 16777220 -n 6

The hdr_meta log line appears only for poc 0, although all 6 AUs carry the SEI (visible in any bitstream viewer).

Reproduction via FFmpeg (per-frame side data count, hevc_rkmpp vs software hevc): the repo includes scripts/compare_hdr_dynamic.sh. On RK3576 and RK3588 (kernel 5.10/6.1) it reports hw=1 sw=6 on both primary streams, hw=1 sw=1 on the control.