Values now carried over frame to frame.
Change to algorithm for decreasing threshold after
a hit and to max threshold (now based on speed)
Removed some old commented out code relating to
VP8 adaptive thresholds.
The impact of these changes tested on Akiyo (50 frames)
and measured in terms of unit rd hits is as follows:
Speed 0 84.36 -> 84.67
Speed 1 29.48 -> 22.22
Speed 2 11.76 -> 8.21
Speed 3 12.32 -> 7.21
Encode speed impact is broadly in line with these.
Change-Id: I5b886efee3077a11553fa950d796fd6d00c8cb19
Most of the focus so far has been on inter frames.
At high speed settings the key frame is now taking a high %
of the cycles.
This patch puts in some masking to reduce the number
of INTRA modes searched during key frame coding (as already
happens for inter frames) at higher speed settings
TODO: Develop this further with either adaptive rd thresholds
when choosing which intra modes to consider or some other
heuristic.
Impact.
At high speed settings on some clips the key frame was starting
to dominate. In a coding of the first 50 frames of AKIYO at speed
2 limiting the key frame intra modes to DC or TM_PRED resulted in
~30% overall speedup. For Bus the number was lower at ~4-5%.
Change-Id: I7bde68aee04995f9d9beb13a1902143112e341e2
Cleans up the switchable filter search logic. Also adds a
speed feature - a variance threshold - to disable filter search
if source variance is lower than this value.
Results: derfraw300
threshold = 16, psnr -0.238%, 4-5% speedup (tested on football)
threshold = 32, psnr -0.381%, 8-9% speedup (tested on football)
threshold = 64, psnr -0.611%, 12-13% speedup (tested on football)
threshold = 96, psnr -0.804%, 16-17% speedup (tested on football)
Based on these results, the threshold is chosen as 16 for speed 1,
32 for speed 2, 64 for speed 3 and 96 for speed 4.
Change-Id: Ib630d39192773b1983d3d349b97973768e170c04
Adds a speed feature to disable split partition search based on a
given threshold on the source variance. A tighter threshold derived
from the threshold provided is used to also disable horizontal and
vertical partitions.
Results on derfraw300:
threshold = 16, psnr = -0.057%, speedup ~1% (football)
threshold = 32, psnr = -0.150%, speedup ~4-5% (football)
threshold = 64, psnr = -0.570%, speedup ~10-12% (football)
Results on stdhdraw250:
threshold = 32, psnr = -0.18%, speedup is somewhat more than derf
because of a larger number of smoother blocks at higher resolution.
Based on these results, a threshold of 32 is chosen for speed 1,
and a threshold of 64 is chosen for speeds 2 and above.
Change-Id: If08912fb6c67fd4242d12a0d094783a99f52f6c6
Adds a new subpel motion estimation function that uses a 2-level
tree-structured decision tree to eliminate redundant computations.
It searches fewer points than iterative search (which can search
the same point multiple times) but has the same quality roughly.
This is made the default setting at speeds 0 and 1, while at
speed 2 and above only a 1-level search is used.
Also includes various cleanups for consistency and redundancy removal.
Results:
derf: +0.012% psnr
stdhd: +0.09% psnr
Speedup of about 2-3%
Change-Id: Iedde4866f5475586dea0f0ba4cb7428fba24eee9
The low precision 32x32 fdct has all the intermediate steps within
16-bit depth, hence allowing faster SSE2 implementation, at the
expense of larger round-trip error. It was used in the rate-distortion
optimization search loop only.
Using the low precision version, in replace of the high precision one,
affects the compression performance by about 0.7% (derf, stdhd) at
speed 0. For speed 1, it makes derf set down by only 0.017%.
Change-Id: I4e7d18fac5bea5317b91c8e7dabae143bc6b5c8b
Removes some unused code and speed features, and organizes the
interfaces for fractional mv step functions for use in new speed
features to come.
In the process a new speed feature - number of iterations per
step during the subpel search - is exposed.
No change when this parameter is set as the original value of 3.
Results:
subpel_iters_per_step = 3: baseline
subpel_iters_per_step = 2: psnr -0.067%, 1% speedup
subpel_iters_per_step = 1: psnr -0.331%, 3-4% speedup
Change-Id: I2eba8a21f6461be8caf56af04a5337257a5693a8
Adds a few pattern searches to achieve various tradeoffs
between motion estimation complexity and performance.
The search framework is unified across these searches so that a
common pattern search function is used for all. Besides it will
be easier to experiment with various patterns or combinations
thereof at different scales in the future.
The new pattern search is multi-scale and is capable of using
different patterns at different scales.
The new hex search uses 8 points at the smallest scale
and 6 points at other scales.
Two other pattern searches - big-diamond and square are
also added. Big diamond uses 4 points at the smallest scale and
8 points in diamond shape at the larger scales.
Square is very similar conceptually to the default n-step search
but is somewhat faster since it keeps only one survivor across
all scales.
Psnr/speed-up results on derf300:
hex: -1.6% psnr%, 6-8% speed-up
big-diamond: -0.96% psnr, 4-5% speedup
square: -0.93% psnr, 4-5% speedup
Change-Id: I02a7ef5193f762601e0994e2c99399a3535a43d2
Adds a speed feature to skip all intra modes other than
DC_PRED if the source variance is small. This feature is
made part of speed 1 and up.
Results on derf300: psnr -0.07%, speedup about 1-2%
Also uses the source variance to fine-tune the early
termination criteria when FLAG_EARLY_TERMINATE is on.
This feature is made part of speed 2 and up.
Results on derf300: psnr -0.52%, speedup about 5-7%
Change-Id: I59e38aa836557cfa5405ae706fc64815cbfe4232
use_min_partition_size and use_max_partition_size are not used
currently, and could be added back if needed later.
Change-Id: Ib22a9c06b064567a7c1d6d5445567ed77e0d3acc
Speed feature experiment to set an upper and lower
partition size limit based on what has been seen
in spatial neighbors.
This seems to gives quite reasonable speed gains in local
(10-15%) and when used with speed 0 the losses are small
(0.25% derf, 0.35% stdhd). However, for now I am only
enabling it on speed 1 as there may be clashes with the existing
temporal partition selection in speed 2.
Using a tighter min / max around the range derived from the
neighbors increases speed further but at the cost of a
bigger quality loss. However, I think this spatial method could
be combined with data from either the last frame or a variance
method (or both) to refine the range of minimum and maximum
partition size. I.e. consider the min and max from spatial and
temporal neighbors and the variance recommendation.
Change-Id: I1b96bf8b84368d6aad0c7aa600fe141b4f07435f
Renamed:
MAX_MB_SEGMENTS to MAX_SEGMENTS
MB_SEG_TREE_PROBS to SEG_TREE_PROBS
The minimum unit for segmentation in the segment map
is now 8x8 so it is misleading to use MB_ as macro-block
traditionally refers to a 16x16 region.
Change-Id: I0b55a6f0426bb46dd13435fcfa5bae0a30a7fa22
Mode search order in rd loop changed to better reflect
observed hit counts.
Also some adjustment of the baseline mode rd thresholds
to reflect the order change and observed frequencies.
Change-Id: I47a131cc83e11551df8add6d6d8d413d78d3a63c
This patch modifies the auto_mv_step_size speed feature to
use a combination of the maximum magnitude mv from the last
inter frame, and the maximum magnitude mv for the two reference
mvs with the same reference. For arf frames, the max mav step
for the resolution is used.
The bounds therefore are slightly tighter. The feature is made
a speed 1 feature.
Rebased.
Results (when this feature is turned on over speed 0):
derfraw300: -0.046% psnr, about 5+% speedup
(tested on football: goes from 4m30.760s to 4m17.410s).
Change-Id: If492797a61b0b4b3e58c0b8f86afb880165fc9f6
these are only used in the encoder.
frames_since_golden / frames_till_alt_ref_frame -> VP[89]_COMP
Change-Id: Ie14a6f46987bced685ddb449b85dc261caba6dfe
Current partition checking starts from small sizes, and then goes up
to large sizes. This experiment uses the small partitions' motion
estimation result, which is already available, to speed up the
large partition's motion estimation. We can decide to skip some
patition checkings if they are unlikely choices. We could use the
motion vector(MV) result as current partition's prediction MV, limit
the search range and reference frame.
Current result at speed 1:
psnr loss: 1.19% for stdhd, 0.287% for derf.
speed gain: 14% for sunflower(hd), 11% for akiyo.
Further improvement will be done later.
Change-Id: I5abfd070e9cace2e91e2a0247d1325df313887ab
Use an estimate based on DC_PRED for intra uv cost
within the rd loop then only do a full uv mode analysis
if an intra mode is chosen.
Significant speed gains in some cases. Currently only
enabled for speed 2 pending speed/quality tests.
Change-Id: Ie851a12400d5483bce47ec0e3ccb8516041e91c0
This speed feature allows the encoder to largely remove the spatial
dependency between blocks inside a 64x64 superblock, thereby removing
the need to repeatedly encode superblocks per partition type in the
rate-distortion optimization loop.
A major challenge lies in the intra modes tested in the rate-distortion
optimization loop. The subsequent blocks do not have access to the
reconstructed boundary pixels without the intermediate coding steps.
This was resolved by using the original pixels for intra prediction
in the rd loop, followed by an appropriately designed distortion
modeling on the quantization parameters. Experiments also suggested
that the performance impact is more discernible at lower bit-rate/psnr
settings. Hence a quantizer dependent threshold is applied to deactivate
skip of block coding.
For bus_cif at 2000 kbps,
speed 0: runtime 269854ms -> 237774ms (12% speed-up) at 0.05dB
performance loss.
speed 1: runtime 65312ms -> 61536ms, (7% speed-up) at 0.04dB
performance loss.
This operation is currently turned on in settings of speed 1.
Change-Id: Ib689741dfff8dd38365d8c1b92860a3e176f56ec
Implements some of the helper functions more efficiently with
lookups rathers than branches. Modeling function is consolidated
to reduce some computations.
Also merged the two enums BLOCK_SIZE_TYPES and BlockSize into
one because there is no need to keep them separate (even though
the semantics are a little different).
No bitstream or output change.
About 0.5% speedup
Change-Id: I7d71a66e8031ddb340744dc493f22976052b8f9f
Adds a speed feature to eliminate full-rd computation if the modeled
rd or rd based on a different parameter in the same mode is already
a lot larger than the best rd yet.
Specifically, only search the sharp and smooth filters if the modeled
rd cost based on the regular filter is within a certain factor of the
best rd cost so far. Also, skip full-rd computation of non splitmv
inter modes if the modeled rd cost based on pred error is within the
same factor of the best rd cost so far.
Also adds some enhancements in the rd search for splitmv mode to
speed things up by early breakouts. Negligible impact on performance.
Resuts on derfraw300:
psnr: -0.013% with the splitmv enhancements, -0.24% with the rd
breakout feature on.
speedup: 6% with splitmv enhancements, 20% with also residual breakout
(tested on football sequence at 600 Kbps)
Change-Id: I37abc308ea9f110c1679ce649b6a7e73ab1ad5fc
Overall, on all test sets, this gains about +0.2% on all metrics.
City is a clip where this really hurts (-1.0% on all metrics), I'm
not quite sure why yet. Maybe interesting to look into in the future.
Change-Id: I6f0eecb20e72f0194633270d30bf00d76d9eae78
Skips mode searches for intra and compound inter modes depending
on the best mode so far and the reference frames. The various
heuristics to be used are selected by bits from a flag. The
previous direction based intra mode search pruning is also absorbed
in this framework.
Specifically the flags and their impact are:
1) FLAG_SKIP_INTRA_BESTINTER (skip intra mode search for oblique
directional modes and TM_PRED if the best so far is
an inter mode)
derfraw300: -0.15%, 10% speedup
2) FLAG_SKIP_INTRA_DIRMISMATCH (skip D27, D63, D117 and D153
mode search if the best so far is not one of the closest
hor/vert/diagonal directions.
derfraw300: -0.05%, about 9% speedup
3) FLAG_SKIP_COMP_BESTINTRA (skip compound prediction mode
search if the best so far is an intra mode)
derfraw300: -0.06%, about 7-8% speedup
4) FLAG_SKIP_COMP_REFMISMATCH (skip compound prediction search
if the best single ref inter mode does not have the same ref
as one of the two references being tested in the compound mode)
derfraw300: -0.56%, about 10% speedup
Change-Id: I1a736cd29b36325489e7af9f32698d6394b2c495
sf->unused_mode_skip_lvl. Tests modes as normal for all
sizes at or below the given level. At larger sizes it skips
all modes that were not chosen at any smaller size.
Hence setting BLOCK_SIZE_SB64X64 is in effect off.
Setting BLOCK_SIZE_AB4X4 will only consider modes that
were chosen for one or more 4x4 blocks at larger sizes.
sf->reference_masking.
Do a test encode of the NONE partition at one size and create
a reference frame mask based on the best rd choice. In the
full search only allow this reference frame.
Currently it is testing 64x64 and repeats this in the full search.
This does not work well with Jim's Partition code just now and
is disabled by default.
Change-Id: I8f8c52d2ef4a0c08100150b0ea4155d1aaab93dd
This commit adds a speed feature where only squared partition are
evaluated in partition picking. Enable this feature in cpu-used 2
reduces encoding time by ~30%.
loss of compression:
-0.9% on cif set
-1.23% on stdhd
Change-Id: Ia6fad11210f0b78365abb889f9245604513be5b9
This speed feature will skip searching the directional intra prediction
modes D63, D117, D27, D153 if the best intra mode so far is not one of
the diagonal, horizontal or vertical directions closest to the respective
directions being tested. In other words, this implements a sort of
binary search in the angular domain.
Speedup: about 9-10%
Results: -0.05% only on derfraw300.
Change-Id: I413584c41f2a3e8dabfbdeb40718c8fc4b1d63a2
(1) Refines the modeling function and uses that to add some speed
features. Specifically, intead of using a flag use_largest_txfm as
a speed feature, an enum tx_size_search_method is used, of which
two of the types are USE_FULL_RD and USE_LARGESTALL. Two other
new types are added:
USE_LARGESTINTRA (use largest only for intra)
USE_LARGESTINTRA_MODELINTER (use largest for intra, and model for
inter)
(2) Another change is that the framework for deciding transform type
is simplified to use a heuristic count based method rather than
an rd based method using txfm_cache. In practice the new method
is found to work just as well - with derf only -0.01 down.
The new method is more compatible with the new framework where
certain rd costs are based on full rd and certain others are
based on modeled rd or are not computed. In this patch the existing
rd based method is still kept for use in the USE_FULL_RD mode.
In the other modes, the count based method is used.
However the recommendation is to remove it eventually since the
benefit is limited, and will remove a lot of complications in
the code
(3) Finally a bug is fixed with the existing use_largest_txfm speed feature
that causes mismatches when the lossless mode and 4x4 WH transform is
forced.
Results on derf:
USE_FULL_RD: +0.03% (due to change in the tables), 0% encode time reduction
USE_LARGESTINTRA: -0.21%, 15% encode time reduction (this one is a
pretty good compromise)
USE_LARGESTINTRA_MODELINTER: -0.98%, 22% encode time reduction
(currently the benefit of modeling is limited for txfm size selection,
but keeping this enum as a placeholder) .
USE_LARGESTALL: -1.05%, 27% encode-time reduction (same as existing
use_largest_txfm speed feature).
Change-Id: I4d60a5f9ce78fbc90cddf2f97ed91d8bc0d4f936
Added a speed feature in speed 1 to disable splitmv for HD (>=720)
clips. Test result on stdhd set: 0.3% psnr loss and 0.07% ssim
loss. Encoding speedup is 36%.
(For reference: The test result on derf set showed 2% psnr loss
and 1.6% ssim loss. Encoding speedup is 34%. SPLITMV should be
enabled for small resolution videos.)
Change-Id: I54f72b94f506c6d404b47c42e71acaa5374d6ee6
This cl converts use partition from last frame to do the following:
if part is none,horz, vert -> try split
if part != none and one of the children is not split - try none
Change-Id: I5b6c659e35f3ac9f11c051b92ba98af6d7e8aa87
Signed-off-by: Jim Bankoski <jimbankoski@google.com>
