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
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
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
Using surrounding reconstructed pixels from left and above to select
best matching mv to use as reference motion vector for mv encoding.
Test results:
AVGPSNR GLBPSNR VPXSSIM
Derf: 1.107% 1.062% 0.992%
Std-hd:1.209% 1.176% 1.029%
Change-Id: I8f10e09ee6538c05df2fb9f069abcaf1edb3fca6
This allows building on MountainLion as the 10.6 SDK has been
removed from the latest Xcode version (4.4 4F250). Also fix
all warnings for that build.
Change-Id: Ib70bca4a25295f13595f0d10ea9f0229631de5a4
Merged in the high_precision_mv experiment to make it easier
to work on new mv encoding strategies. Also removed
coef_update_probs3().
Change-Id: I82d3b0bb642419fe05dba82528bc9ba010e90924
Set on all 16x16 intra/inter modes
Features:
- Butterfly fDCT/iDCT
- Loop filter does not filter internal edges with 16x16
- Optimize coefficient function
- Update coefficient probability function
- RD
- Entropy stats
- 16x16 is a config option
Have not tested with experiments.
hd: 2.60%
std-hd: 2.43%
yt: 1.32%
derf: 0.60%
Change-Id: I96fb090517c30c5da84bad4fae602c3ec0c58b1c
Merged the enhanced_interp experiment.
Found and fixed a bug in the include files framework, whereby
certain encoder files were still using the old INTERP_EXTEND
value of 3 instead of 4. The thresholds for mv range mcomp.c
need a small adjustment to prevent crashes.
The results are more or less unchanged.
Change-Id: Iac5008390f1efc97ce1102fbb5f8989c847fb579
Allows for swtiching/setting interpolation filters at the MB
level. A frame level flag indicates whether to use a specifc
filter for the entire frame or to signal the interpolation
filter for each MB. When switchable filters are used, the
encoder chooses between 8-tap and 8-tap sharp filters. The
code currently has options to explore other variations as well,
which will be cleaned up subsequently.
One issue with the framework is that encoding is slow. I
tried to do some tricks to speed things up but it is still slow.
Decoding speed should not be affected since the number of
filter taps remain unchanged.
With the current version, we are up 0.5% on derf on average but
some videos city/mobile improve by close to 4 and 2% respectively.
If we did a full-search by turning the SEARCH_BEST_FILTER flag
on, the results are somewhat better.
The framework can be combined with filtered prediction, and I
seek feedback regarding that.
Rebased.
Change-Id: I8f632cb2c111e76284140a2bd480945d6d42b77a
The following five experiments are merged:
newentropy
newupdate
adaptive_entropy (also includes a couple of parameter changes
that improves results a little
in common/entropymode.c and encoder/modecosts.c
that were not merged from the internal branch)
newintramodes
expanded_coef_context
Change-Id: I8a142a831786ee9dc936f22be1d42a8bced7d270
Added the ability to optionally filter the prediction data
when inter modes are selected (excludes SPLITMV, for now).
The mode selection loop considers both the filtered and
non-filtered prediction data when choosing mode. The filter
can be turned on/off at the frame-level, or signaled for
each MB.
Change-Id: I1b783c71d95a361ab36c761b07e8a6b06bc36822
Incorporates mv_ref, mbsplit and second_mv into the adaptive
entropy framework. The mv_ref framework has been modified from
before.
Adds some clean-ups and fixes.
Results with the adaptive entropy experiment are currently up by
+1.93% on derf; +2.33% std-hd and +1.87% yt-hd.
Fixed a nasty intermittent bug.
Change-Id: I4b1ac9f9483b48432597595195bfec05f31d1e39
This patch incorporates adaptive entropy coding of coefficient tokens,
and mode/mv information based on distributions encountered in a frame.
Specifically, there is an initial forward update to the probabilities
in the bitstream as before for coding the symbols in the frame, however
at the end of decoding each frame, the forward update to the
probabilities is reverted and instead the probabilities are updated
towards the actual distributions encountered within the frame.
The amount of update is weighted by the number of hits within each
context.
Results on derf/hd/std-hd are all up by 1.6%.
On derf, the most of the gains come from coefficients, however for the
hd and std-hd sets, the most of the gains come from the mode/mv
information updates.
Change-Id: I708c0e11fdacafee04940fe7ae159ba6844005fd
This commit is to remove two arrays, which contain the probabilities
of how likely each probability in coef_probs table is updated. The
commit changed to use a fixed number "252".
Surprisedly, the overall impact on quality is close to zero, which
basically says the two big static arrays are not helpful at all.
derf: -0.016%, -0.020%
std-hd: 0.000%, -0.013%
yt: -0.022%, +0.007%
yt-hd: -0.038%, +0.034%
Change-Id: Ifee94d28a37dcab4f1d2b994bd5b07575be42b72
This commit added the ability to accumulate the coef stats across
different encodings using an intermediate binary stats files. The
accumulation happens only the binary stats file exists in current
directory. The encoder needs to be built with "ENTROPY_STATS" to
allow the output. The commit also fixed a few formating issues in
output stats file.
Change-Id: Ib1a41180aa554845cf51e4421a230b128a3a82b4
Variables m & mi were being dereferenced when they might
hold invalid values.
The fix is simply to move these dereferences to after the
point at which mb_row and mb_col are tested for validity.
Change-Id: Ib16561efa9792dc469759936189ea379d374ad20
the commit fixed a number of compiling issues when some epxeriments
are turned on at the same time.
Change-Id: Idb15b215e2d2a7d25f2707f99ef55a34e7301ce7
The commit changed how baseline 8x8 coefficient probabilities are
initialized, to be consistent with the initialization of baseline
4x4 coefficient probabilities.
The commit does not have any effect on compression.
Change-Id: Ifb3902b5dc0b0c2e6dc3aa5d4a6589d528e58355
I now see I didn't write a very long description, so let's do it
here then. We took a pretty big quality hit (0.1-0.2%) from my
recent fix of the inversion of arguments to vp8_cost_bit() in the
RD reference frame costing. I looked into it and basically the
costing prevented us from switching reference frames. This is of
course silly, since each frame codes its own prob_intra_coded, so
using last frame cost indications as a limiting factor can never
be right.
Here, I've rewritten that code to estimate costings based partially
on statistics from progress on current frame encoding. Overall,
this gives us a ~0.2%-0.3% improvement over what we had previously
before my argument-inversion-fix, and thus about ~0.4% over current
git (on derf-set), and a little more (0.5-1.0%) on HD/STD-HD/YT.
Change-Id: I79ebd4ccec4d6edbf0e152d9590d103ba2747775
1. block types
There are only three types of blocks for 8x8 transformed MBs, i.e. Y
block with DC does not exist for 8x8 transformed MBs as all MB using
8x8 transform have 2nd order haar transform. This commit introduced
a new macro BLOCK_TYPES_8X8 to reflect such fact.
2. context counters
This commit also fixed the mixed of context_counters between 4x4 and
8x8 transformed MBs. The mixed use of the counters leads me to think
the existing the context probabilities were not properly generated
from 8x8 transformed MBs.
3. redundant collecting in recoding
The commit also corrected the code that accumulates entropy stats by
making sure stats only collected for final packing, not during the
recode loop
Change-Id: I029f09f8f60bd0c3240cc392ff5c6d05435e322c
This commit merge the QI mode experiment. As the experiment affects
the encoding of intra coding modes on key frame only, the overall
effect of the experiment on encoding tests is insignificant.
Change-Id: I9e4e3933adface88867ad429cee3986e529c511d
The commit merges the UVINTRA experiment and removed the related
macros. The overall effect of the experiment is a small gain (.1%
on derf)
Change-Id: Ia34b3312fb9b5b34c9ba111bf0fa78c6f78ac80b
Adds differential encoding of prob updates using a subexponential
code centered around the previous probability value.
Also searches for the most cost-effective update, and breaks
up the coefficient updates into smaller groups.
Small gain on Derf: 0.2%
Change-Id: Ie0071e3dc113e3d0d7ab95b6442bb07a89970030
With the NEWENTROPY experiment enabled encoding certain clips
produced invlid bitstreams, or files that had a high degree
of artefacts.
This was the results of pointers in MACROBLOCKD not being
setup correctly (mode_info_context and prev_mode_info_context).
Change-Id: Ice13e1efa8bd122997d2f8f3f1e761c6c16e0403
Some code re-factored / moved to allow the main
pack operation inside the recode loop so that the
size estimate is accurate.
Deletion of some redundant code relating to one pass.
Aproximate improvement over March 27 code base:
Derf 0.0%, YT 0.5%, YThd 0.3% Std_hd 0.25%
Change-Id: Id2d071794ab44f0b52935f6fcdb5733d09a6bb86
This is the first patch to add superblock (32x32) coding
order capabilities. It does not yet do any mode selection
at the SB level, that will follow in a further patch.
This patch encodes rows of SBs rather than
MBs, each SB contains 2x2 MBs.
Two intra prediction modes have been disabled since they
require reconstructed data for the above-right MB which
may not have been encoded yet (e.g. for the bottom right
MB in each SB).
Results on the one test clip I have tried (720p GIPS clip)
suggest that it is somewhere around 0.2dB worse than the
baseline version, so there may be bugs.
It has been tested with no experiments enabled and with
the following 3 experiments enabled:
--enable-enhanced_interp
--enable-high_precision_mv
--enable-sixteenth_subpel_uv
in each case the decode buffer matches the recon buffer
(using "cmp" to compare the dumped/decoded frames).
Note: Testing these experiments individually created
errors.
Some problems were found with other experiments but it
is unclear what state these experiments are in:
--enable-comp_intra_pred
--enable-newentropy
--enable-uvintra
This code has not been extensively tested yet, so there
is every likelihood that further bugs remain. I also
intend to do some code cleanup & refactoring in tandem
with the next patch that adds the 32x32 modes.
Change-Id: I1eba7f740a70b3510df58db53464535ef881b4d9
Found this bug while tracking down some anomalies in my experiments.
Since vp8_cost_one and vp8_cost_zero return unsigned int, the
bit shift by 8 will be incorrect if the value is negative.
I am cautiously optimistic that this fix will make the prob
updates more correct and somewhat improve results across the board.
But the update probabilities will need to be retuned I think.
Patch 2: Adding more of the same fixes using a macro.
Change-Id: I1a168f040e74e8c67e7225103b1c2af9a611da49
Various refactoring to make the subpel motion compensation
filters switchable by a frame level field.
Two types of 8-tap filters are supported in addition to the existing
bilinar and sixtap filters. One is the default 8-tap and the
other has a sharper cut-off for use with frames with substantial
edge content.
Patch 2: Added a preliminary strategy for filter selection based on
edginess detecton. Also includes some filter changes.
Change-Id: I866085bda5ae143cfdf2ec88157feaabdf7bd63a
Pulled out super block code for the snapshot as this
is not quite ready and will need an extensive re-merge.
Change-Id: I436369b511257447a7b0ea064016cb63f5011849
This gives a modest gain on derf overall, although at low bitrates the
cost is still too high, so this can be improved further.
Patch 2. Re-base and fix 80 column issues
Change-Id: Ida2f9fa3fe75370669f6a27b37108dc602231c63
