we don't need to centralize best_uv[] since target_uv[] and best_rgb_uv[]
are already centralized. The diff 'W' was just in the ~[-2,2] range, so
we can ignore the correction.
Overall speed-impact is not large, though. Around ~4% faster conversion.
Output with -pre 4 is expected to be slightly different
Change-Id: Ib59f033955577c49b084d0560108020f42d84102
also: remove the useless clipping in StoreGray()
For speed reason, the 'gray' plane was initialized with the same
value for 2x2 block. But in some cases (underlying camera noise, e.g.),
it could lead to instability during iteration, noise amplification,
and visible banding.
Using a precise (but slower) initialization solves the issue, and
since the convergence is faster, we might actually gain some speed.
Change-Id: I81c42101497e7096a8f60289d710f5a3bcb0ddea
We usually need at least 2 iterations to converge
(and usually not much more after that). Only 1 was not enough.
Change-Id: Iaf802ea81afa2596f4ba045c92f5eaff61623b7b
Change it from transparent white to transparent black, which matches
the transparent color assumed in Webp dispose-to-background method.
Also pre-multiply background colors before comparison in anim_diff,
just as what is done with regular pixel values.
Change-Id: I5a790522df21619c666ce499f73e42294ed276f2
Set enc->prev_candidate_undecided_ as 0 when a frame is not chosen
as a possible keyframe, so that the dispose method can be
dispose-to-background.
Change-Id: If2899f5dbc06fb53705fb8240072ab6440a6de12
No need to find backward references for pixels in uniform regions
by looking at all pixels.
Only pixels at the same distance from the end need to be compared to.
Change-Id: I4f187e965f0667d3a929775726a412f7e69f6473
if src_{r,g,b} = 0, any value of src_a or dst_a such that
abs(src_a - dst_a) <= max_allowed_diff
was making the test pass, despite being very different-looking pixels.
The fix is to require same values for src_a and dst_a before attempting
an r/g/b comparison.
Change-Id: If3a55a229eab3904ed454f20065e49e35c39f25c
Constants are such that brute force is sometimes faster for some
data (mostly big images it seems).
Change-Id: I90aef536408683535e3b09ddfa2e77a9834038f6
gcc-4.8.3 was giving the undefined reference to ImgIoUtilReadFile and
ImgIoUtilCopyPlane when linking libimagedec.a
Change-Id: I8b85ab3a860602535629d0bb541a39754413728e
Return key/index if the query is found, and -1 otherwise.
The benefit of this is to save a hashing computation.
Change-Id: Iff056be330f5fb8204011259ac814f7677dd40fe
WEBP_HAVE_FLAG_LOCAL -> WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG} this will
include the flag being tested in the output:
-- Performing Test WEBP_HAVE_FLAG_NEON
Change-Id: I1c0a143a857b16e4eb1fcf8b23c176380a5fef29
