The 0016 patch declared ff_h264_set_mb_inspect_cb in h264dec.h and
defined it in h264_mb.c, but didn't touch libavcodec/libavcodec.v.
FFmpeg's default version script exports only `av_*`, `avcodec_*`,
`avpriv_*`, and `avsubtitle_free`; everything else is hidden as LOCAL
behind a `*` glob. Result: `nm -D libavcodec.so.62 | grep
ff_h264_set_mb_inspect_cb` returned nothing → dlsym() returned NULL.
Static-link CLI consumer (daedalus_decode_h264) was unaffected
because static linking doesn't care about symbol visibility. The
daedalus-v4l2 daemon shadow_decoder path (PR-Q3a.1) dlopens
libavcodec.so.62 and resolves the callback via dlsym — that needs
the symbol exported.
Fix: add ff_h264_set_mb_inspect_cb to the global list in
libavcodec/libavcodec.v. Single-line addition to the 0016 patch.
Mirrored across the arch/ + debian/ patch trees.
PKGREL bump 14 → 15, changelog entry added (debian side). PKGBUILD
pkgrel bumped on arch side too. No behaviour change to the decode
path: the callback is still opt-in via the H264Context function
pointer; only consumers that have explicitly installed a callback
pay the one-load-one-branch cost per MB.
dejavu-check: this is fixing the existing 0016 observation-hook to
actually work as a dlsym intercept (the architectural shape the
patch was designed for). NOT adding new per-kernel substitution.
Same shape, same patch number, same intent. Just hiding/exporting
plumbing.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
marfrit
25610930ad