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
Change-Id: Ic812e64ae5f70251c170b0717f7b7fa587055488
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.
Change-Id: I2aaa6874fa10ce05c958dd182947ce39f6f1eecb
High Q end extended a little.
Some clean up.
Slightly better on SSIM, Slightly worse on PSNR over derf set.
Change-Id: I3dceea8a39e11c26e1a389a40e40b86efc76d28c
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)
Change-Id: I2f7117de8adc1797164c106aa13effc900a1467e
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%:
http://www.corp.google.com/~yaowu/no_crawl/interUVintra.html
The gain looks to be reasonable given inta coded MBs is only a
small portion of MBs in inter frames.
Change-Id: Ic6fc261923f2c253f4a0c9f8bccf4797557b9e16
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%
http://www.corp.google.com/~yaowu/no_crawl/newNearMode_1209.html
Change-Id: I7b3e32ec8729de1903d14a3f1213f1624b78cdee
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.
Change-Id: I525f927f68e2365d37b340ef23b836a136a4f70b
This commit removed the macro CONFIG_I8X8, which was used to indicate
the 8x8 intra prediction experiment, made the change fully merged in.
Change-Id: Iafa4443781ce6e83f5591c12ba615a0e92ce0ea0
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%.
http://www.corp.google.com/~yaowu/no_crawl/newModeContext.html
Change-Id: Ia62b14485c948e2b74586118619c5eb2068b43b2
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.
Change-ID: I59dc84b07cbb3ccf073ac0f756d03d294cb19281
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%.
http://www.corp.google.com/~yaowu/no_crawl/mulcontext.html
Change-Id: I15bc9697f6ff7829042911fe0c62930585d7e65d
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.
Change-Id: I398ada49dfc32575cfab962a569c2885111ae3ba
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.
Change-Id: I36186267d55dfc2a3d565d0cff7218ef300d1cd5
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.
Change-Id: Id0eeaba6cc854c6d1be00ed8d237b3d9e250e447
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.
Change-Id: Iddf6cf5ea8467c44b7c133f38e629f6ba6f2581e
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.
Change-Id: Ief1e284a36d8aa56b49ae5b360c91419ec494fa4
Corrected dc lookup table to maintain ac/dc balance
close to what it was previously.
Firstpass not being passed the adjusted Q index for
the extended range.
Change-Id: Ic0200dabda445fea03bf81067999cb2670e99b77
Removal of CONFIGURE_SEGMENTATION ifdefs.
Removal of legacy support code fo the old coding mechanism.
Use local reference "xd" for MACROBLOCKD structure in
encode_frame_to_data_rate()
Moved call to choose_segmap_coding_method() out of encode
loop as the cost of segmentation is not properly accounted
in the loop anyway. If this is desirable in the future it
can be moved back. The use of this function to do all the
analysis and set the probabilities also removes the need
to track segment useage in threading code.
Change-Id: I85bc8fd63440e7176c73d26cb742698f9b70cade
Changed name and sense of segment_flag to "seg_id_predicted"
Added some additional comments and retested.
I also did some experimentation with a spatial prediction option
using a similar strategy to the temporal mode implemented.
This helps in some cases where temporal prediction is bad but
I suspect there is more overlap here with work on a larger scale
block structure and spatial correlation will likely be better
handled through that mechanism.
Next check in will remove #ifdefs and legacy mode code.
Change-Id: I3b382b65ed2a57bd7775ac0f3a01a9508a209cbc
This check in includes quite a lot of clean up and refactoring.
Most of the analysis and set up for the different coding options for the
segment map (currently simple distribution based coding or temporaly
predicted coding), has been moved to one location (the function
choose_segmap_coding_method() in segmenation.c). This code was previously
scattered around in various locations making integration with other
experiments and modification / debug more difficult.
Currently the functionality is as it was with the exception that the
prediction probabilities are now only transmitted when the temporal
prediction mode is selected.
There is still quite a bit more clean up work that will be possible
when the #ifdef is removed. Also at that time I may rename and alter
the sense of macroblock based variable "segment_flag" which indicates
(1 that the segmnet id is not predicted vs 0 that it is predicted).
I also intend to experiment with a spatial prediction mode that can be
used when coding a key frame segment map or in cases where temporal
prediction does not work well but there is spatial correlation.
In a later check in when the ifdefs have gone I may also move the call
to choose_segmap_coding_method() to just before where the bitsream is
packed (currently it is in vp8_encode_frame()) to further reduce the
possibility of clashes with other experiments and prevent it being called
on each itteration of the recode loop.
Change-Id: I3d4aba2a2826ec21f367678d5b07c1d1c36db168
the bug caused the encoder to produce invalid bitstream when configured
with enable_extend_qrange.
Change-Id: I1e81c48b13359d0043cbbd480e679380a2da117c
logically this commit should NOT change anything, but seems to help
revert the 3DB loss on bowing in the following commit:
https://on2-git.corp.google.com/g/#change,6193
This is still debugging in progress. Need further investigation to
understand the root cause of the issue.
Change-Id: I0b49d1ef3a311dfff58c6acd3eaebdb3bda6257c
Initial attempt at using new segment feature signaling
to indicate 4x4 or 8x8 transform.
needs --enable-experimental --enable-t8x8
Note this is work in progress.
Change-Id: Ib160d46a5d810307bfcbc79853ce1a65b5b870b7
Temporary check in to turn off other segment features
tests when #if CONFIG_T8X8 is set as the assignment of
MBs to differnt segments in each case will conflict.
The 8x8 code will be modified to use the new segment
feature method properly in a later check in.
Increase bits allowed for EOB end stop marker to 6 ready
for 8x8.
Change-Id: I4835bc8d3bf98e1775c3d247d778639c90b01f7f
No change to functionality or output.
Updates to the segment feature data structure now all done
through functions such as set_segdata() and get_segdata()
in seg_common.c.
The reason for this is to make changing the structures (if needed)
and debug easier.
In addition it provides a single location for subsequent addition
of range and validity checks. For example valid combination of
mode and reference frame.
Change-Id: I2e866505562db4e4cb6f17a472b25b4465f01add
This commit tries to do UV intra mode coding adaptive to Y intra mode.
Entropy context is defined as conditional PDF of uv intra mode given
the Y mode. All constants are normalized with 256 to be fit in 8 bits.
This provides further coding efficiency beyond the quantizer adaptive
y intra mode coding. Consistent gains were observed on all clips and
all bit rates for HD all key encoding tests.
To test, configure with
--enable-experimental --enable-uvintra
Change-Id: I2d78d73f143127f063e19bd0bac3b68c418d756a
Removal of configure #ifdefs so that segment features
always available. Removal of code supporting old
segment feature method.
Still a good deal of tidying up to do.
Change-Id: I397855f086f8c09ab1fae0a5f65d9e06d2e3e39f
Modify reference frame segmentation so that ONE or MORE
reference frames may be marked as a available for a given
segment.
Fixed bugs relating to segment coding of INTRA and some
INTER modes at the segment level.
Modified Q boost for static areas based on ambient average Q.
Strong results now on clips with significant static areas.
(some data points in derf set as high as 9% and some static &
slide show type content in YT set > 20%)
Change-Id: Ia79f912efa84b977f35a23683ae3643251e24f0c
Prior to the added rounding, tests on randomly generated data showed
that forward-inverse transform round trip errors are about 3.02/block
for input range [-10,10] and 2.68/block for input range [-256, 255].
The added rounding reduced the errors to 0.031/block for input range
[-10,10] and 0.037/block for input range [-256, 255].
Maximum round trip error on for any pixel position is 1.
The average errors are calculated based on 100,000 blocks of randomly
with the specified ranges.
Paul mentioned in discussion that the change was not clear on why we
need change the rounding, so Patch 2 intends to make the rationale
obvious in code, it merged the two separate shifts into one, and the
two separate rounding factors into one. Patch 1 and 2 have same
numerical test results.
Change-Id: Ic5e2f5463de17253084d8b2398c4a210194b20de
Only encode sign bit for feature data that can have a sign.
Tweaks to the test segmentation rules so that it now actually gives
a net benefit on the derf set of about 0.4% though much higher
on some clips at the low end.
Change-Id: I8e61f1aebf41c9037db7e67e2f8975aa18a0c986
This quite large check in includes the following:
Merge in some code from Ronald (mbgraph.c) that scans a Gf/arf group.
This is used as a basis for a simple segmentation for the normal frames
in a gf/arf group. This code also uses satd functions from Yaowu.
Adds functionality for coding the latest possible position of an EOB for
blocks in the segment. (Currently 0-15 only, hence just for 4x4 dct).
Where the EOB position is 0 this acts like "skip" and the normal coding
of skip at the per mb level is disabled.
Added functions (seg_common.c) for setting and reading segment feature
elements. These may want to be optimized away at some point but while the
mecahnism is in a state of flux they provide a single location for making
changes and keep things a bit cleaner.
This is still proof of concept code. Currently the tested feature set:-
Quantizer,
Loop Filter level,
Reference frame,
Prediction Mode,
EOB end stop.
TBD:-
Add functions for setting and reading the feature data with range
and validity checking.
Handling of signed and unsigned feature data. At the moment all is assumed
to be signed and a sign bit is coded but many cannot be negative.
Correct handling of EOB feature with intra coded blocks.
Testing/trapping of legal/illegal ref frame and mode combinations.
Transform size switch plus merge and test with 8c8 DCT work
Merge and test with Sumans Segmenation coding optimizations
Change-Id: Iee12e83661c7abbd1e0ce6810915eb4ec35e2d8e
This commit added a 3 bit index to the bitstream, the index is used to
look into the intra mode coding entropy context table. The commit uses
the mode stats to calculate the cost of transmitting modes using 8
possible entropy distributions, and selects the distribution that
provides the lowest cost to do the actual mode coding.
Initial test show this provides additional .2%~.3% gain over quantizer
adaptive intra mode coding. So the adaptive intra mode coding provides
a total of .5%(psnr) to .6% gain(ssim) combined for all-key-encoding
To build and test, configure with
--enable-experimental --enable-qimode
Change-Id: I7c41cd8bfb352bc1fe7c5da1848a58faea5ed74a
make intra mode coding entropy distribution adaptive to baseQindex, an
encoding test on hd clips with all key frame shows universal gain on
all clips in both .2%(psnr) and (ssim).3%.
To build and test, configure with
--enable-experimental --enable-qimode
Change-Id: Iaa69241b984d4fdd8baa6d77ee78c0140f5ac00a
Patch 1 to Patch 3 is an initial implementation of 8x8 intra prediction
modes, here are with the following assumptions:
a. 8x8 has 4 prediction modes DC, H, V and TM
b. UV 4x4 block use the same mode as corresponding 8x8 area
c. i8x8 modes are enabled for key frame only for now
Patch 4:
d. removed debug code from previous patches
Patch 5:
e. added stats code to collect entropy stats and further cleaned up
Patch 6:
f. changed mode stats code to collect finer stats of modes
Patch 7:
g. normalized i8x8 modes distribution to total at 256 (8bits).
Patch 8:
h. fixed a bug in decoder and removed debug printf output.
Patch 9:
i. more cleanups to address paul's comment
Patch 10:
j. messy rebase/merges to bring the commit up to date.
Tests on HD clips encoded with all key frame showing consistent gain
on all clips and all metrics:~0.5%(psnr) and 0.6%(ssim):
http://www.corp.google.com/~yaowu/no_crawl/i8x8hd_allkey_fixedq.html
To build and test, configure with:
--enable-experimental --enable-i8x8
Change-Id: I9813fe07ae48cab5fdb5d904bca022514ad01e7f
This data structure is now [Segment ID][Features]
rather than [Features][Segment_ID]
I propose as a separate modification to make the experimental
bit stream reflect this such that all the features for a segment
are coded together.
Change-Id: I581e4e3ca2033bdbdef3d9300977a8202f55b4fb
Some basic plumbing added for a range of segment level features.
MB_LVL_* changed to SEG_LVL_* to better reflect meaning.
Change-Id: Iac96da36990aa0e40afc0d86e990df337fd0c50b
for SPLITMV and B_PRED modes. Modified code to use the bmi
found in mode_info_context instead of BLOCKD. On the decode
side, the uvmvs are calculated only when required, instead of
every macroblock. This is WIP. (bmi should eventually be
removed from BLOCKD)
Small performance gains noticed for RT encodes and decodes.(VGA)
Change-Id: I2ed7f0fd5ca733655df684aa82da575c77a973e7
Prepend idct function names with vp8_
so that under profiling they show up
associated with libvpx.
Change-Id: I4fe357b50236cb7730a4cc00164c0a3487a1d8b4
