avcodec/h274: Make H274FilmGrainDatabase a shared objectHEADmaster

Right now, the private contexts of every decoder supporting
H.274 film grain synthesis (namely H.264, HEVC and VVC)
contain a H274FilmGrainDatabase; said structure is very large
700442B before this commit) and takes up the overwhelming
majority of said contexts: Removing it reduces sizeof(H264Context)
by 92.88%, sizeof(HEVCContext) by 97.78% and sizeof(VVCContext)
by 99.86%. This is especially important for H.264 and HEVC
when using frame-threading.

The content of said film grain database does not depend on
any input parameter; it is shareable between all its users and
could be hardcoded in the binary (but isn't, because it is so huge).

This commit adds a database with static storage duration to h274.c
and uses it instead of the elements in the private contexts above.
It is still lazily initialized as-needed; a mutex is used
for the necessary synchronization. An alternative would be to use
an AV_ONCE to initialize the whole database either in the decoders'
init function (which would be wasteful given that most videos
don't use film grain synthesis) or in ff_h274_apply_film_grain().

Reviewed-by: Niklas Haas <[email protected]>
Signed-off-by: Andreas Rheinhardt <[email protected]>

0 files changed, 0 insertions, 0 deletions