Paul Wilkins [Thu, 9 Feb 2012 15:44:18 +0000 (15:44 +0000)]
Dual pred flag
Further changes to make experiments with the context
used for coding the dual pred flag easier.
Current best performing method tested on derf is a two
element context based on reference frame. I also tried
various combinations of mode and reference frame as
shown in commented out case using up to 6 contexts.
Derf +0.26 overall psnr +0.15% ssim vs original method.
We should only change the dual prediction mode if we actually entered
the recode branch. Else, it may potentially undo beneficial changes
to the dual prediction mode in the first encode iteration.
Some conditions were conditional under a threshold, whereas they should
always execute. Also, some conditions were testing an array instead of
the values within it.
Paul Wilkins [Fri, 3 Feb 2012 17:08:37 +0000 (17:08 +0000)]
Move update of ref frame probabilities in encode loop.
The existing code updated the reference frame probabilities before
the test to evaluate the impact of using updated probabilities
in vp8_estimate_entropy_savings().
The estimate of cost and savings is still basic and does not reflect
the new prediction code but this would require per MB costings
and the benefit is probably marginal, as this is really just used for
rate estimation in the loop.
Paul Wilkins [Fri, 3 Feb 2012 15:10:44 +0000 (15:10 +0000)]
Merged NEWNEAR experiment
This commit merges the NEWNEAR experiment such that it
is effectively always on.
The fact that there were changes in the threading code again
highlights the need to strip out such features during the
bitstream development phase as trying to maintain this code
(especially as it is not being tested) slows the development cycle.
Paul Wilkins [Thu, 2 Feb 2012 17:30:27 +0000 (17:30 +0000)]
Coding the hybrid dual prediction signal.
Initial modifications to make limited use of common prediction
functions.
The only functional change thus far is that updates to the probabilities are
no longer "damped". This was a testing convenience but in fact seems to
help by a little over 0.1% over the derf set.
Paul Wilkins [Fri, 3 Feb 2012 13:46:18 +0000 (13:46 +0000)]
Modified prediction behavior for reference frame.
Trial of a modified prediction function that ranks each possible
reference frame based on a combination of local usage and
frame level probability. The code is a bit cleaner and simpler.
In direct comparison with old unpredicted method with segment level
coding turned off for mode,ref & EOB the prediction gives a gain on derf
of around 0.4%. There is some further gain from bug fixes over earlier code.
With segment coding on the prediction method is slightly -ve on some very
easy clips (at low rates) due to slightly higher overheads, but better on harder
clips. Overall neutral on derf in direct comparison on latest code base, but
compared to earlier code without bug fixes about +0.7% overall psnr
+0.3% SSIM.
Adrian Grange [Thu, 2 Feb 2012 17:04:40 +0000 (09:04 -0800)]
Added encoding in Superblock Order
As a precursor to encoding 32x32 blocks this cl adds the
ability to encode the frame superblock (=32x32 block) at
a time. Within a SB the 4 indiviual MBs are encoded in
raster-order (NW,NE,SW,SE).
This functionality is added as an experiment which can be
enabled by ispecifying --enable-superblocks in the
command line specified to configure (CONFIG_SUPERBLOCKS
macro in the code).
To make this work I had to disable the two intra
prediction modes that use data from the top-right of the
MB.
On the tests that I have run the results produce
almost exactly the same PSNRs & SSIMs with a very
slightly higher average data rate (and slightly higher
data rate than just disabling the two intra modes in
the original code).
NOTE: This will also break the multi-threaded code.
This replaces the abandoned change:
Iebebe0d1a50ce8c15c79862c537b765a2f67e162
Yaowu Xu [Wed, 1 Feb 2012 22:49:10 +0000 (14:49 -0800)]
Fixes a decoder bug
The bug was introduced by the commit that added I8X8 intra prediction
mode for inter frames, the decoder was not update to accept the additional
probability update from encoder. This causes the decoder typicall to crash
when encoder sends intra mode probability update.
Paul Wilkins [Sat, 28 Jan 2012 10:07:08 +0000 (10:07 +0000)]
Added common prediction modules.
This function adds the common prediction modules, some data structures
and a config option but does not use them.
It also corrects a bug in clearing down the MODE_INFO border and introduces
a new element that indicates if an entry corresponds to an "in image" macro block
or is part of the border.
Deb Mukherjee [Mon, 30 Jan 2012 17:27:44 +0000 (09:27 -0800)]
Refining the 8-tap interpolation filters.
Fixes a rounding issue with the 8-tap filters, which allows us to
use sharper filters that before with a little better performance.
Results on derf (0verall gain 0.76):
http://www.corp.google.com/~debargha/vp8_results/enhinterp.html
Results on a 720P set (Overall gain 0.61):
http://www.corp.google.com/~debargha/vp8_results/enhinterp_hd.html
Yaowu Xu [Thu, 26 Jan 2012 22:36:20 +0000 (14:36 -0800)]
fixed an issue with 8x8 token cost in trellisquant
changed the token cost for 8x8 transformed macroblock used in trellisquant
from those derived from 4x4 transform coefficient distribution to those
derived from 8x8 transform coefficient distribution. Test results show
this fix help 8x8 transform based compression consistently on cif and hd
sets:
Note: To test the effect of this change, 8x8 transform was forced to be used
only on 16x16 predicted macroblocks on inter frames, the effect would be
bigger had all macroblocks been forcd to use 8x8 transform.
Deb Mukherjee [Mon, 16 Jan 2012 19:21:12 +0000 (11:21 -0800)]
Adds support for enhanced interpolation for subpel motion
using an 8-tap filter.
The results with 3 different 8-tap filters on the derf set are in:
http://www.corp.google.com/~debargha/vp8_results/enhinterp.html
The one that gives the most gain achieves an overall gain of about
0.6%. The results for a set of 12 hd (720p) videos are in:
http://www.corp.google.com/~debargha/vp8_results/enhinterp_hd.html
with max gain of 0.55% with the same filter. The best filter apparently
achieves the best trade-off between pass band ripple and stop band
attenuation.
Jim Bankoski [Mon, 23 Jan 2012 17:55:23 +0000 (09:55 -0800)]
vpn common -> implicit segmentation
This introduces base functions for introducing implicit segmentation.
The code that actually stores the results to the segment map isn't
here yet. This just prints out the segmentation map results
if you call it.
Uses connected component labeling technique on mbmi info so that only
if 2 mbs are horizontally or vertically touching do they get the same
segment.
vp8next - plumbing for rotation
code to produce taps for rotation ( tapify. py ), code
for predicting using rotation ( predict_rotated.c ) , code
for finding the best rotation find_rotation.c.
didn't checkin code that uses this in the codec. still work
in progress.
Yaowu Xu [Wed, 30 Nov 2011 16:05:45 +0000 (08:05 -0800)]
changed loop filter for MBs using 8x8 transform
This commit added a set of loop filter functions for macroblocks
using 8x8 transform. First we turned off the regular loop filtering
on 4x4 block boundaries that do not exist in macroblocks using 8x8
transform. Second, we change to use the same loop filter(mask and
7 tap filter) that used for macroblock edge filtering.
Yaowu Xu [Fri, 20 Jan 2012 00:37:32 +0000 (16:37 -0800)]
Added code to prevent I8X8_PRED mode for MBs using 8x8 transform
This fixed a conflict introduced by the change of adding 8x8 intra
prediction modes. The 8x8 intra prediction mode code assumed the
use of 4x4 transform, and causes encoder crashes when the codec is
configured with --enable-t8x8.
Yaowu Xu [Fri, 13 Jan 2012 22:37:17 +0000 (14:37 -0800)]
new loop filter functions for macroblock boundaries
The commit adds a new set of loop filter for macroblock edge filtering.
The new loop filter has a mask to detect so-called "flat" regions. The
detection checks 5 pixels of each side of an edge. If the all pixels
have value with +/-1 from the edge pixel on the same side, the region
is treated as a "flat" region. For such case, a 7 tap filter is used
to change 3 pixel values on each side. The 7 taps are:
[1, 1, 1, 2, 1, 1, 1]/8
The furthest away pixels used as input are +/-5 away from edge. For
non-flat region, we fall back to old filtering. It should be noted
here that the thresholds and filter taps may require more optimization
for best possible results.
Tests on a set of hd clips showed consistent gains:
http://www.corp.google.com/~yaowu/no_crawl/mblpf_hd.html
(avg psnr: .83% glb psnr: .77% ssim: .82%)
Tests on derf set also showed consistent gains:
http://www.corp.google.com/~yaowu/no_crawl/mblpf_derf.html
(avg psnr: .24% glb psnr: .22% ssim: .48%)
Paul Wilkins [Wed, 11 Jan 2012 14:05:57 +0000 (14:05 +0000)]
Rate control on static scenes plus Y2dc delta Q fix.
A problem can arise on static clips with force key frames where
attempts to avoid popping lead to a progressive reduction in key
frame Q that ultimately may lead to unexpected overspend against
the rate target.
The changes in this patch help to insure that in such clips the
quality of the key frames across the clip is more uniform (rather
than starting bad and getting better - especially at low target rates).
This patch also includes a fix that removes a delta on the Y2DC
when the baseline q index < 4 as this is no longer needed.
There is also a fix to try and prevent repeat single step Q adjustment in
the recode loop leading to lots of recodes, especially where the use
of forced skips as part of segmentation has made the impact of Q on
the number of bits generated much smaller.
Patch 2: Amend "last_boosted_qindex" calculation for arf overlay frames.
Yaowu Xu [Thu, 5 Jan 2012 19:22:06 +0000 (11:22 -0800)]
Added an emms to prevent invalid stats output
In certain hardware configuration, where mmx code is enabled and
other simd (sse2/sse3) disabled, lacking of this emms caused invalid
internal stats outputs.
Yaowu Xu [Wed, 21 Dec 2011 20:05:10 +0000 (12:05 -0800)]
changed mode_context update strategy
Previously, the mode context is always udpated based on stats of current
frame, when there is no count, 50% is used for both left and right branch.
However, it is observed that with such strategy, a small count or no count
at all can skew the probability distribution significantly. This commmit
changed the mode_context update strategy to prevent small counts from
skewing the probability distributions.
Tests on derf set showed a small gain: .06% in psnr and .09% in ssim
Paul Wilkins [Fri, 16 Dec 2011 10:23:01 +0000 (10:23 +0000)]
Extend to 256 Q steps.
This commit extends the number of Q steps to 256 from 128.
The q_trans[] array has been altered to distribute available Q index values
(using the current 64 steps available as input parameters) evenly across the
available range. This is coupled with the fact that each Q step where possible
now equates to a fixed % change in the quantizer. This may want refinement
later especially in terms of the granularity at the high quality end but is a
reasonable starting point.
Paul Wilkins [Mon, 12 Dec 2011 18:27:25 +0000 (18:27 +0000)]
Further QIndex realted Fixes:
Added code to support 256 index steps instead of 128 but disabled for now.
Replace hard wired table vp8cx_base_skip_false_prob[128]
Observed Qindex problem with setting minimum loop filter value.
(Experiment code using real Q in place but for now just returning 0. This has a big
beneficial effect on some clips, particularly waterfall which shows 5% ssim gain)
Adrian Grange [Fri, 16 Dec 2011 22:00:36 +0000 (14:00 -0800)]
Reset segment_id to 0 when segmentation is disabled
Whilst the encoder explicitly set the segment_id to 0
when segmentation is diabled, the decoder would allow
the segment_id to persist from the previous frame.
This fix attempts to make the decoder behave the same
as the encoder by explicitly setting the segment_id to
0 in this case.
Adrian Grange [Thu, 15 Dec 2011 18:00:46 +0000 (10:00 -0800)]
Fixed bug to use mode_info_stride rather than mb_cols
Both encoder & decoder were using mb_cols to
offset from one row of MODE_INFO structures to the next
when they should have been using mode_info_stride.
Fixing this in both encoder and decoder gives around
a 3KB size saving and 0.025dB PSNR improvement on the one
720P clip I tried.
(Also removed "index" which was being updated but not used)
Yaowu Xu [Thu, 8 Dec 2011 19:43:09 +0000 (11:43 -0800)]
Enabled adaptive UV intra coding for inter frames
Previously, Y-adaptive UV intra coding only enabled on key frames in
UVINTRA experiment. This commit enabled the same coding for inter
frames, so the encoding of UV intra modes are consistent cross all
frame types. Tests on derf set showed a very small overall gain around
.04%:
Yaowu Xu [Thu, 8 Dec 2011 19:43:09 +0000 (11:43 -0800)]
Revised coding using adaptive mode context to depend on frame type
A previous commit 76feb965 made the vp8_mode_context adaptive on a frame
frame basis, this commit further made the coding context adaptive to two
frame types separately. Tests on derf set showed a further small gain on
all metrics: avg psnr 0.10%, glb psnr: 0.11%, ssim: 0.08%
Yaowu Xu [Thu, 8 Dec 2011 04:08:31 +0000 (20:08 -0800)]
fixed a crash caused invalid Q choice
The commit fixed a problem by capping cpi->active_best_quality to be
smaller than cpi->worst_quality. Also fixed a few line of code that
was misplaced.
Yaowu Xu [Wed, 7 Dec 2011 21:55:58 +0000 (13:55 -0800)]
Removed #if CONFIG_MULCONTEXT
This commit removed the macro CONFIG_MULCONTEXT, which was used to
indicate the experiment code for using separate context for altref
and normal frames. This commit made the change fully merged in.
Yaowu Xu [Tue, 6 Dec 2011 20:03:42 +0000 (12:03 -0800)]
made vp8_mode_context adaptive
vp8_mode_contexts[] is an entropy table used to code inter mode
choices. It was a fixed constant table. This commit made the entropy
context adaptive. Tests on derf set showed very good consistent gains
on all metrics: avg psnr .47%, overall psnr .46% and ssim .40%.
Yaowu Xu [Tue, 6 Dec 2011 15:37:39 +0000 (07:37 -0800)]
fixed a crash when MODE_STATS is enabled
The MODE_STATS macro was used to #ifdef around code for mode entropy
stats collection, this commit fixed a crash when MODE_STATS is on.
The commit also changed a number of array definitions to use defined
macros instead of hard-coded numbers.
This patch introduces the concept of dual inter16x16 prediction. A
16x16 inter-predicted macroblock can use 2 references instead of 1,
where both references use the same mvmode (new, near/est, zero). In the
case of newmv, this means that two MVs are coded instead of one. The
frame can be encoded in 3 ways: all MBs single-prediction, all MBs dual
prediction, or per-MB single/dual prediction selection ("hybrid"), in
which case a single bit is coded per-MB to indicate whether the MB uses
single or dual inter prediction.
In the future, we can (maybe?) get further gains by mixing this with
Adrian's 32x32 work, per-segment dual prediction settings, or adding
support for dual splitmv/8x8mv inter prediction.
Gain (on derf-set, CQ mode) is ~2.8% (SSIM) or ~3.6% (glb PSNR). Most
gain is at medium/high bitrates, but there's minor gains at low bitrates
also. Output was confirmed to match between encoder and decoder.
Note for optimization people: this patch introduces a 2nd version of
16x16/8x8 sixtap/bilin functions, which does an avg instead of a
store. They may want to look and make sure this is implemented to
their satisfaction so we can optimize it best in the future.
Paul Wilkins [Tue, 6 Dec 2011 14:48:52 +0000 (14:48 +0000)]
Some further QIndex issues with extended Q
Resolved or factored out some further issues with Q index.
Put in a 3rd order polynomial instead of less accurate power function
as the best fit on gf and kf boost adjustment.
Added avg_q value to use instead of ni_av_qi.
Compute segment delta Q values based on avg_q.
Fixed bug in adjust_maxq_qrange().
The extended range Q on the derf set, using standard data rates
(which do not extend high enough to get big benefits) still show
a shortfall of between 0.5 and 1% though so there would appear to
be further issues that need to be tracked down.
Yaowu Xu [Fri, 2 Dec 2011 23:32:46 +0000 (15:32 -0800)]
changed configure script to enable new experimental options
Added two experimental options to the configure script:
1. newnear:
new scheme of doing mv encoding that include a motion vector from
last frame in nearest and near mv search
2. mulcontext:
tracks entropy context separately for regular frames and alt ref
frames.
Yaowu Xu [Thu, 1 Dec 2011 00:36:46 +0000 (16:36 -0800)]
added separate entropy context for alt_ref
This commit added code to keep track of separate entropy contexts for
normal frames and alt ref frames. The underly assumption was that the
two type of frames have different entropy characteristics given they
typically have quite different quantization levels. By keeping entropy
contexts separate, it helps the entropy context distribution to be more
closely adapted to each frame type.
Tests on derf set showed a good and very consistent gain on all clips
on all metrics, avg psnr: 0.89%, overall psnr: 0.84% and ssim 0.93%.
Yaowu Xu [Thu, 1 Dec 2011 00:25:00 +0000 (16:25 -0800)]
enabled 8x8 intra prediction modes on inter frames
This commit enabled the usage of 8x8 intra prediction modes on inter
frames. There are a few TODO items related to this: 1)baseline entropy
need be calibrated; 2)cost of UV need to be done more properly rather
than using decision only relying on Y; 3)Threshold for allowing picking
8x8 intra prediction should be lowered to lower than the B_PRED.
Even with all the TODOs, tests showed consistent gain on derf set ~0.1%
(PSNR:0.08% and SSIM:0.14%). It is assumed that 8x8 intra prediction
will help more on large resolution clips, especially with above TODOs
addressed.
Paul Wilkins [Fri, 2 Dec 2011 14:57:21 +0000 (14:57 +0000)]
Further work on extended Q range.
Fixed some further QIndex related issues and replaced some tables
(eg zbin and rounding)
Also Added function (currently disabled by default) to populate the
main AC and DC quantizer tables. Using the original AC range the
resulting computed DC values give behavior broadly comparable
on the DERF set. That is not to say that the equations will hold good
over a more extended range. The purpose of this code is to make it
easier to experiment with further alterations to the Q range and distribution
of Q values plus the relative weights given to AC and DC.
The function find_fp_qindex() ensures that changes to the Q tables
are reflected in the value passed in to the first pass code.
Slight experimental adjustment to static segment Q offset.
Yaowu Xu [Fri, 18 Nov 2011 02:31:00 +0000 (18:31 -0800)]
added transform type to MB_MODE_INFO
this commit is to add an variable in the macroblock level mode
info structure to track the transform size used in each MB, so
the information can be used later in the loop filter to change
how loop filter works on MBs with different transform sizes.
Paul Wilkins [Thu, 24 Nov 2011 18:25:03 +0000 (18:25 +0000)]
Further work on extended Q range.
Fixed bug in firspass.c call to vp8_initialize_rd_consts()
This was passing in vp8_dc_quant(cm->base_qindex, cm->y1dc_delta_q)
instead of (cm->base_qindex + cm->y1dc_delta_q).
It just so happens that for the value 26 used for cm->base_qindex in the
unextended Q case, the two give similar results. However, when using
the extended Q range the two are very different.
Also added more stats output and partly disabled another broken feature.
Yaowu Xu [Wed, 16 Nov 2011 00:16:30 +0000 (16:16 -0800)]
changed find_near_mvs search to include a mb from last frame
This is an experiment to include a mv contribution from last frame to
nearest and near mv definition. Initial test showed some small though
consistent gain.
latest patch slightly better result ~.13%-~.18%.
TODO: the entropy used to encode the mode choice, i.e. the mv counts
based conditional distribution of modes should be re-collected to
reflect this change, it is expected that there is some further gain
from that.
Paul Wilkins [Wed, 23 Nov 2011 17:18:31 +0000 (17:18 +0000)]
Two pass rate control code changes.
This comitt brings accross changes from the public branch
commit number Icf74d13af77437c08602571dc7a97e747cce5066.
The main puurpose of this comit relates to CQ mode but it
also includes some refactoring of the two pass code which
I hope will make tuning the experimental branch for the new
quantizer range a little less painfull.
Paul Wilkins [Wed, 23 Nov 2011 11:32:20 +0000 (11:32 +0000)]
Further resolution of QIndex LUTS;
This commit resolves further QIndex look up tables to facilitate
experimentation with the quantizer range.
In some cases rather than remove the look up tables completely
I have created functions that are called once to populate them
using a formulaic approach base on the actual quantizer.
The use of these functions based on best fit of data from the original
tables does affect the results on some clips but across the derf test
set the effect was broadly neutral.
Paul Wilkins [Mon, 21 Nov 2011 15:45:10 +0000 (15:45 +0000)]
Removal of Qindex LUTS.
One of the problems arising when tweaking or adjusting the quantizer
tables is that there are a lot of look up tables that depend on the QINDEX.
Any adjustment to the link between QINDEX and real quantizer therefore tends
to break aspects of for example the rate control.
In this check in I have replaced several of the look up tables with functions that
approximate the same results as the old Q luts but use a formulaic approach
based on real Q values rather than QIndex. This should hopefully make it easier
to experiment with changes to the Q tables without always having to go through
and hand optimize a set of look up tables. Once things stabilize we may choose
to re-instate luts for the sake of performance.
Patch 2:
Addressed Ronald's comments.
vp8_init_me_luts() Added so luts only initialized once.
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