The high-precision (1/8) pel bit is turned off if the reference
MV is larger than a threshold. The motivation for this patch is
the intuition that if motion is likely large (as indicated by
the reference), there is likley to be more motion blur, and as
a result 1/8 pel precision would be wasteful both in rd sense
as well as computationally.
The feature is incorporated as part of the newmventropy experiment.
There is a modest RD improvement with the patch. Overall the
results with the newmventropy experiment with the threshold being
16 integer pels are:
derf: +0.279%
std-hd: +0.617%
hd: +1.299%
yt: +0.822%
With threshold 8 integer pels are:
derf: +0.295%
std-hd: +0.623%
hd: +1.365%
yt: +0.847%
Patch: rebased
Patch: rebase fixes
Change-Id: I4ed14600df3c457944e6541ed407cb6e91fe428b
Some cleanups that will make it easier to maintain the code
and incorporate upcoming changes on entropy coding for the
hybrid transforms.
Change-Id: I44bdba368f7b8bf203161d7a6d3b1fc2c9e21a8f
This commit merges those parts of the CONFIG_NEW_MVREF
that specifically relate to choosing a better set of candidate
MV references into the NEWBESTREFMV experiment.
CONFIG_NEW_MVREF will then be used for changes relating
to the explicit coding of a cost optimized MV reference in the
bitstream as part of MV coding.
Change-Id: Ied982c0ad72093eab29e38b8cd74d5c3d7458b10
Extend experiment to use both vectors from MBs
coded using compound prediction as candidates.
In final sort only consider best 4 candidates
for now but make sure 0,0 is always one of them.
Other minor changes to new MV reference code.
Pass in Mv list to vp8_find_best_ref_mvs().
Change-Id: Ib96220c33c6b80bd1d5e0fbe8b68121be7997095
Adds a new experiment with redesigned/refactored motion vector entropy
coding. The patch also takes a first step towards separating the
integer and fractional pel components of a MV. However the fractional
pel encoding still depends on the integer pel part and so they are
not fully independent. Further experiments are in progress to see
how much they can be decoupled without affecting performance.
All components including entropy coding/decoding, costing for MV
search, forward updates and backward updates to probability tables,
have been implemented.
Results so far:
derf: +0.19%
std-hd: +0.28%
yt: +0.80%
hd: +1.15%
Patch: Simplifies the fractional pel models:
derf: +0.284%
std-hd: +0.289%
yt: +0.849%
hd: +1.254%
Patch: Some changes in the models, rebased.
derf: +0.330%
std-hd: +0.306%
yt: +0.816%
hd: +1.225%
Change-Id: I646b3c48f3587f4cc909639b78c3798da6402678
Enable ADST/DCT of dimension 16x16 for I16X16 modes. This change provides
benefits mostly for hd sequences.
Set up the framework for selectable transform dimension.
Also allowing quantization parameter threshold to control the use
of hybrid transform (This is currently disabled by setting threshold
always above the quantization parameter. Adaptive thresholding can
be built upon this, which will further improve the coding performance.)
The coding performance gains (with respect to the codec that has all
other configuration settings turned on) are
derf: 0.013
yt: 0.086
hd: 0.198
std-hd: 0.501
Change-Id: Ibb4263a61fc74e0b3c345f54d73e8c73552bf926
The transform functions in experimental branch absorbed a scaling
factor of 4 to allow quantization steps closer to unit quantizer.
This commit added scaling code in between forward and inverse
transform to properly account for the scaling factor.
Change-Id: I9a573ddc1ffa74973b34800a5da1a56dbabe0949
Alternative strategy for finding a list of candidate motion
vectors to use as reference values in mv coding and as
nearest and near.
Sort by sad in vp8_find_best_ref_mvs() rather than just
pick the best. Allow 0,0 as a best ref option but not a
nearest or near unless there are no alternatives.
Encode/Decode verified on at least some clips.
Some commented out experimental and stats code still in place.
Gain over existing code averages about 1% on derf (alll metrics)
with improvement on all clips. Other test results pending.
The entropy coding of the mode (nearest/near etc) still
depends upon and requires the old "findnear" code so
this needs looking at and may provide room for further gains.
Change-Id: I871d7cba1d1c379c4bad9bcccce1fb19c46b8247
Added missing parameters to calls to:
vp8_build_intra_predictors_internal
vp8_build_intra_predictors_mbuv_internal
Change-Id: If8eeb8ff23eff4572397b404fe61be5d0c950bbe
This commit adds a pick_sb_mode() function which selects the best 32x32
superblock coding mode. Then it selects the best per-MB modes, compares
the two and encodes that in the bitstream.
The bitstream coding is rather simplistic right now. At the SB level,
we code a bit to indicate whether this block uses SB-coding (32x32
prediction) or MB-coding (anything else), and then we follow with the
actual modes. This could and should be modified in the future, but is
omitted from this commit because it will likely involve reorganizing
much more code rather than just adding SB coding, so it's better to let
that be judged on its own merits.
Gains on derf: about even, YT/HD: +0.75%, STD/HD: +1.5%.
Change-Id: Iae313a7cbd8f75b3c66d04a68b991cb096eaaba6
Resolved the decoder mismatch issue due to quantization parameter
threshold for hybrid transform coding. The macroblock dequantizer
initialization is moved to be performed before coefficient
detokenization, since the (de)tokenization is now dependent on the
macroblock level quantization parameter.
Change-Id: I443da4992ebb70ae4114750b2f1363c0c628580e
This doesn't affect the result, since there are no MVs coded using this
entropy. It does, however, silence valgrind warnings about uninitialized
variables.
Change-Id: I6e21ba92df6ce5381bf58b8c349ef4373294a0b6
