The modified error was a derivative of the "coded_error"
that was used to allocate bits between different frames on the
assumption that the allocation should be linear in terms of this
modified error. I.e. a frame with double the modified error score
should all things being equal get double the number of bits. The
code also included upper and lower caps derived from input
VBR parameters.
This patch improves the initial calculation of the clip mean error
(now called "mean_mod_score" as it is no longer a prediction error)
used as the midpoint for the rate distribution function and normalizes
the output "modified scores" scores such that 1.0 indicates a frame
in the middle of the distribution. The VBR upper and lower caps are
then applied directly to a frame's normalized score.
This refactoring is intended to make it easier to drop in alternative
distribution functions or to base the rate allocation on a corpus wide
midpoint (rather than the clip mean).
Change-Id: I4fb09de637e93566bfc4e022b2e7d04660817195
Most existing first pass stats are stored in a form normalized to a
macro-block scale. However the error scores for intra / inter etc were
stored as frame level values but mainly used as MB level values.
This change fixes that. Normalized per MB values make comparisons
between different formats easier and in any case this is usually what is
wanted.
An change in results should be limited to slight differences in rounding.
*** Change after patch 8 +2 requiring new approval.
Final pre-submit testing showed one 4K clip with above expected change.
Investigation showed this was due to a value used to test for ultra low intra
complexity in key frame detection. This was a per frame not per MB value but
also did not scale with frame size. Replacement with a small per MB value
(based on original per frame value and cif frame size) resolved the KF detection
problem.
Also converted kf_group_error_left to a double in line with other error values
to reduce rounding problems in KF group bit allocation
All clips and sets now show nominal (or 0) change as expected.
Change-Id: Ic2d57980398c99ade2b7380e3e6ca6b32186901f
Modified the code to facilitate bit-match tests in first pass
Added unit-tests to test the row based multi-threading behavior for bit-exactness
Change-Id: Ieaf6a8f935bb1075597e0a3b52d9989c8546d7df
(yunqingwang)
1. Rebased the patch. Incorporated recent first pass changes.
2. Turned on the first pass unit test.
Change-Id: Ia2f7ba8152d0b6dd6bf8efb9dfaf505ba7d8edee
One of the first pass stats "new_mv_count" is no longer used in VP9,
and is removed. This also makes it easy to implement a multi-threaded
first pass. This change doesn't affect the coding performance, which
has been verified by borg tests.
Change-Id: I4c7c7bf9465fda838eb230814ef0c631c068c903
Use a measure of noise energy to adjust Q estimate and
arf filter strength.
Gains 0.3-0.5% on Lowres and |Netflix sets.
Hdres and Midres neutral.
Change-Id: Ic0de552e7b6763e70eeeaa3651619831b423e151
Added a factor based on the bit spend in the last arf group vs the
target to adjust the choice of the active worst quality in subsequent
groups.
Helps clips where previously there was a big overshoot or undershoot
to adapt and get closer to the target rate.
Change-Id: I67034b801679b99024409489a2273ea6fe23b8e6
The use of this value is preventing rate adjustment on clips
or sections that have very little motion but high noise and
this can give rise to some sections with massive overshoot.
Change-Id: I9a65c7c1148dc5d3a7d8b23e50fc1733f3661621
Uses a metric on fraction of smooth blocks derived from first pass
stats in a frame to adjust down the cq_level modestly in the cq mode.
The current implementation does not add much complexity, and is
fairly light in the adaptation.
Change-Id: Ic484e810d5bd51b7bb6b8945f378c7c3d9d27053
Change speed features / behavior for split mode when there
is an internal active edge (e.g. formatting bars).
Remove some threshold constraints in rd code near the active
edge of the image.
Add some plumbing for left and right active edge detection.
Patch set 5. Limit rd pass through for sub 8x8 to internal active edges.
This takes away any speed penalty for most clips but keeps the enhanced
edge coding for the more critical case of internal image edges
Change-Id: If644e4762874de4fe9cbb0a66211953fa74c13a5
Some initial experiments into discounting dead zone
formating bars and intra skip blocks (common in some
types of animation and graphics) in the calculation of
the active max Q for each ARF/GF group.
TODO: check for vertical formating bars and validate the
horizontal bar at the bottom edge of the image.
As expected, this change as it stands, does not make much
difference for the natural videos in the std-hd and derf sets.
However, for the yt and yt hd set there is a significant rise
in the average PSNR with overall PSNR and SSIM remaining
neutral.
The mean rise for the YT-HD test set was > 6%. This is mainly
because the change allows Q to drop further on titles and
other graphics sections where spending a small number of
extra bits gives a sharp rise in PSNR.
Change-Id: I3f878ae91fc1854312d7ecf9fa792c17bc1aa6b7
For content that is identified as likely to contain some
animation or graphics content, increase the availability
of split modes for good quality speeds 1-3.
On a problem test animation clip this improves metrics
results by about 0.25 db and makes a noticeable difference
visually. It also causes a small drop in file size (~0.5%) but
a rise in encode time of about 5-6% at speed 2.
For more normal content it should have no effect.
Change-Id: Ic4cd9a8de065af9f9402f4477a17442aebf0e439
Adds code to detect dead zone bars at the top and bottom
of reformatted letterbox video (note that the code only
looks at the top of the image and assumes any dead zone
is symmetrical). Use of this to adapt rate control etc.
will follow in a subsequent patch.
Also counts other blocks (excluding the dead zone) that
have no intra signal. The presence of a significant
number of such blocks can be used as a identify that the frame
may be artificial (e.g. animation, screen capture, graphics).
This patch contains plumbing only and does not use
the signal.
Change-Id: I59bc93529cd4065416cef773e405fda3ae006a20
This patch provides a partial rapid feedback of bits
resulting from extreme undershoot.
Some improvement on some problem animated material
but in its current form only a small impact on the metrics results
of our standard test sets.
Change-Id: Ie03036ea8123bc2553437cb8c8c9e7a9fc5dac5d
Note: This feature is still in development.
Add an option for the encoder to decide the resolution
at which to encode each frame.
Each KF/GF/ARF goup is tested to see if it would be
better encoded at a lower resolution. At present, each
KF/GF/ARF is coded first at full-size and if the coded
size exceeds a threshold (twice target data rate) at
the maximum active Q then the entire group is encoded
at lower resolution.
This feature is enabled in vpxenc by setting:
--resize-allowed=1
In addition, if the vpxenc command line also specifies
valid frame dimensions using:
--resize-width=XXXX & --resize_height=YYYY
then *all* frames will be encoded at this resolution.
Change-Id: I13f341e0a82512f9e84e144e0f3b5aed8a65402b
Currently disabled by default: enabled using
#define GROUP_ADAPTIVE_MAXQ
In this patch the active max Q is adjusted for each GF
group based on the vbr bit allocation and raw first pass
group error.
This will tend to give a lower q for easy sections
and a higher value for very hard sections. As such it is
expected to improve quality in some of the easier
sections where quality issues have been reported.
This change tends to hurt overall psnr but help
average psnr. SSIM also shows a small gain.
Average results for derf, yt, std-hd and yt-hd test sets were
as follows (%change for average psnr, overal psnr and ssim):-
derf +0.291, - 0.252, -0.021
yt +6.466, -1.436, +0.552
std-hd +0.490, +0.014, +0.380
yt-hd +5.565, - 1.573, +0.099
Change-Id: Icc015499cebbf2a45054a05e8e31f3dfb43f944a
Make the midpoint variance used in AQ mode 1 segmentation
depend on the overall complexity of the frame in two pass.
Change-Id: I452814ec57f7a32352e41bb250e78066abe952dd
The aim of this patch is to apply a positive weighting to
frames that have a significant number of blocks that are
of low spatial complexity and are dark. The rationale behind
this is that artifacts tend to be more visible in such frames.
In this patch the weight is only applied in regard to the distribution
of bits between frames. Hence if all the frames share similar
characteristics (as is the case for most of our short test clips) there
will be little or no net effect.
However, the effect can be seen on some longer form test content.
For example Tears of steel baseline test:
2323.09 Kbit/s opsnr 39.915 ssim 74.729
With this patch:-
2213.34 Kbit/s opsnr 39.963 ssim 74.808
(Sligtly better metrics and about 5% smaller)
The weighting may well need some further tuning along side changes
to the aq modes.
Change-Id: Ieced379bca03938166ab87b2b97f55d94948904c
Allow min and maxQ to creep when the undershoot
or overshoot exceeds thresholds controlled by the
command line under_shoot_pct and over_shoot_pct
values.
Default is 100%,100% which ~disables adaptation.
Derf results for example undershoot% / overshoot%:-
Head:- Mean abs (%rate error) = 14.4%
This check in:-
25%/25% - Mean abs (%rate error) = 6.7%
PSNR hit -1% SSIM -0.1%
5% / 5% - Mean abs (%rate error) = 2.2%
PSNR hit -3.3% SSIM - 1.1%
Most of the remaining error and most of the quality hit is
at extreme data rates. The adaptation code still has an
exception for material that is in effect static so that we
don't over adjust and over spend on YT slide show type
content.
(Rebase of If25a2449a415449c150acff23df713e9598d64c9
to resolve a auto-merge error)
Change-Id: Iec4e1613ef0d067454751d8220edb7058dfbd816
Allow min and maxQ to creep when the undershoot
or overshoot exceeds thresholds controlled by the
command line under_shoot_pct and over_shoot_pct
values.
Default is 100%,100% which ~disables adaptation.
Derf results for example undershoot% / overshoot%:-
Head:- Mean abs (%rate error) = 14.4%
This check in:-
25%/25% - Mean abs (%rate error) = 6.7%
PSNR hit -1% SSIM -0.1%
5% / 5% - Mean abs (%rate error) = 2.2%
PSNR hit -3.3% SSIM - 1.1%
Most of the remaining error and most of the quality hit is
at extreme data rates. The adaptation code still has an
exception for material that is in effect static so that we
don't over adjust and over spend on YT slide show type
content.
Change-Id: If25a2449a415449c150acff23df713e9598d64c9
In model_rd_for_sb function, the spatial domain SSE and variance
are checked to see if transform coefficients are quantized to 0.
Besides that, this patch adds another set of thresholds that are
much more strict. These thresholds are used to conduct a partition
block level check to measure if all its TX blocks are skippable
for YUV planes. If it is true, x->skip is set for this partition
block, and thus its mode search is terminated.
This speeds up the encoding at very low prediction error case,
such as screen sharing application. This patch covers what
rd_encode_breakout_test() does, so that function is removed.
Borg test at speed 3 shows:
For stdhd set, psnr: +0.008%, ssim: +0.014%;
For derf set, psnr: +0.018%, ssim: +0.025%.
No noticeable speed change.
Change-Id: I4e5f15cf10016a282a68e35175ff854b28195944
Substantial restructuring of the way we estimate
the rate of decay in prediction quality and determine
the arf interval and amount of boost used.
Also other changes to support moving to a lower first pass
Q which exposes some new features and allows us to better
distinguish genuinely static blocks from low motion or noisy
blocks.
Net gains now visible on all the test sets with std-hd PSNR up
1.87%. There are still some bad outlier cases but most of these
are low motion or slide show type content where the metrics
are already high at any given rate. The best + case is up by
more than 10%.
Change-Id: I18e25170053bdf3188f493ff8062f48a74515815
Re-organize the one-byte structure for 16x16 first pass
block. Add bits to indicate motion vector directions.
Change-Id: Id10754ba343dfc712c7fed5bcc85c67fa0bbcb89
The bug sets the wrong pointer to the first pass mb stats
if the encoder does the re-coding in the second pass.
Change-Id: I8a11f45dd7dceb38de814adec24cecccae370d00
2 pass only change to calculation of rd mult based on Q.
Make a small adjustment based on frame type and also
replace adjustment based on iifactor with an one based
on the ambient GF/ARF boost level.
Also fix multi arf bug / issue.
Overall these change give an slight improvement in ssim
but hurt psnr a little.
Change-Id: I5e1751e3ff5390a26f543d7855059e6fbcce105e
Add a conditional compile flag for this feature. Also add a
switch to enable the encoder to use these statistics in the
second pass. Currently, the switch is turned off.
Change-Id: Ia1c858c35ec90e36f19f5cffe156b97ddaa04922
Add indirection to the section of buffer indices.
This is to help simplify things in the future if we
have other codec features that switch indices.
Limit the max GF interval for static sections to fit
the gf_group structures.
Change-Id: I38310daaf23fd906004c0e8ee3e99e15570f84cb
This patch implements a mechanism for inserting a second
arf at the mid position of arf groups.
It is currently disabled by default using the flag multi_arf_enabled.
Results are currently down somewhat in initial testing if
multi-arf is enabled. Most of the loss is attributable to the
fact that code to preserve the previous golden frame
(in the arf buffer) in cases where we are coding an overlay
frame, is currently disabled in the multi-arf case.
Change-Id: I1d777318ca09f147db2e8c86d7315fe86168c865
Use of stack frame variable "fps" beyond the lifetime of the function.
fps is sent as a paremeter to output_stats and stored in the
packet holding this encoded frame. This has scope beyond the
lifetime of the calling function.
This reverts commit 3f95a230c7
Change-Id: Icd8e14b3d7dd733590ada12e619b9dce95b6b0f5
Further changes to first pass allocation for gf/arf groups.
Three variables removed from TWO_PASS structure as only
now used locally. Dont adjust gf_group_bits in the post
encode update as this will no longer have any effect.
Change-Id: Iff89b225db923fc856f5d2aedbc899f1d7d68b55
Restructuring to allocate the bits for each frame in
a GF group at the time the group is defined.
At the moment the allocation closely mirrors what
we had before.
Also changes the default rate adjustment method to
LONG_TERM_VBR_CORRECTION.
Change-Id: Ie5793c46c6b9c888cead5d8790792efd7d60b7c1
