For videos with big static background(such as video conferencing
clips), the mode decision was biased to ZEROMV in order to
obtain a stable background. The percentage of ZEROMV on last
frame was used to predict if there is static area in current frame,
and checking already-encoded neighboring macroblocks' motion
vectors to make sure the local area has low motion.
Change-Id: I05b3241d3a56a0bda88b6681e5646c1c8baf2e57
Added drop_frame support in multi-resolution encoder.
If one frame is dropped at a lower-resolution level, the next
upper-resolution level encoder needs to encode that frame
independently without any lower-resolution level motion
information.
Another issue is that if one frame is dropped at some but not all
resolution levels, a frame after that one may use different set
of reference frames at different resolution levels. This reference
frame asynchronization could degrade motion search precision in
upper-resolution level encoding, which uses lower-resolution level
motion result. This change compares the lower-resolution and upper-
resolution level's reference frames. If they are not the same, the
upper-resolution level encoder can not use lower-resolution level
motion result.
Change-Id: I61afa4f313630e75b7cbdd5742e230e8724a988a
Allows building the library with the gcc -pedantic option, for improved
portabilty. In particular, this commit removes usage of C99/C++ style
single-line comments and dynamic struct initializers. This is a
continuation of the work done in commit 97b766a46, which removed most
of these warnings for decode only builds.
Change-Id: Id453d9c1d9f44cc0381b10c3869fabb0184d5966
Change If4321cc5 fixed a bug caused by forward declarations not being
kept in sync across C files, resulting in a function call with the
wrong arguments. The commit moves the affected function declarations
into a header file, along with the other symbols from encodeframe.c
that were being sloppily shared.
Change-Id: I76a7b4c66d4fe175f9cbef7e52148655e4bb9ba1
These are warnings in most builds, but show up as compile errors on
some platforms when these headers are included from C++ code.
Change-Id: I6c523b4dbbc699075fe73830442b51922e5a61d5
These are warnings in most builds, but show up as compile errors on
some platforms when these headers are included from C++ code.
Change-Id: I6c523b4dbbc699075fe73830442b51922e5a61d5
RD costs were local to MACROBLOCK data and had to be copied all the
time to each thread's MACROBLOCK data. Tables moved to a common place
and only pointers are setup for each encoding thread.
vp8_cost_tokens() generates 'int' costs so changed all types to be
int (i.e. removed unsigned).
NOTE: Could do some more cleaning in vp8cx_init_mbrthread_data().
Change-Id: Ifa4de4c6286dffaca7ed3082041fe5af1345ddc0
Look for changes in the codec's configured w/h instead of its active
w/h when forcing keyframes. Otherwise calls to vp8_change_config()
will force a keyframe when spatial resampling is active.
Change-Id: Ie0d20e70507004e714ad40b640aa5b434251eb32
This change added a motion search skipping mechanism similar
to what we did in second pass. For a macroblock that is very
similar to the macroblock at same location on last frame,
we can set its mv to be zero, and skip motion search. This
improves first-pass performance for slide shows and video
conferencing clips with a slight PSNR loss.
Change-Id: Ic73f9ef5604270ddd6d433170091d20361dfe229
Produce the token partitions on-the-fly, while processing each MB.
Context is updated at the beginning of each frame based on the
previoud frame's counters. Optimally encoder outputs partitions in
separate buffers. For frame based output, partitions are concatenated
internally.
Limitations:
- enabled just in combination with realtime-only mode
- number of encoding threads has to be equal or less than the
number of token partitions. For this reason, by default the encoder
will do 8 token partitions.
- vpxenc supports partition output (-P) just in combination with
IVF output format (--ivf)
Performance:
- Realtime encoder can be up to 13% faster (ARM) depending on the number
of threads and bitrate settings. Constant gain over the 5-16 speed
range.
- Token buffer reduced from one frame to 8 MBs
Quality:
- quality is affected by the delayed context updates. This again
dependents on input material, speed and bitrate settings. For VC
style input the loss seen is up to 0.2dB. If error-resilient=2
mode is used than the effect of this change is negligible.
Example:
./configure --enable-realtime-only --enable-onthefly-bitpacking
./vpxenc --rt --end-usage=1 --fps=30000/1000 -w 640 -h 480
--target-bitrate=1000 --token-parts=3 --static-thresh=2000
--ivf -P -t 4 -o strm.ivf tanya_640x480.yuv
Change-Id: I127295cb85b835fc287e1c0201a67e378d025d76
mode_info_context->mbmi.mb_skip_coeff has to always reflect the
existence or not of coeffs for a certain MB. The loopfilter needs this
info.
mb_skip_coeff is either set by the vp8_tokenize_mb or has to be set to
1 when the MB is skipped by mode selection. This has to be done
regardless of the mb_no_coeff_skip value.
prob_skip_false is needed just when mb_no_coeff_skip is 1. No need to
keep count of both skip_false and skip_true as they are complementary
(skip_true+skip_false = total_mbs)
Change-Id: I3c74c9a0ee37bec10de7bb796e408f3e77006813
Second shot at this...
Sync with loopfilter thread as late as possible, usually just at the
beginning of next frame encoding. This returns control to application
faster and allows a better multicore scaling.
When PSNR packets are generated the final filtered frame is needed
imediatly so we cannot delay the sync. Same has to be done when
internal frame is previewed.
Change-Id: I64e110c8b224dd967faefffd9c93dd8dbad4a5b5
This commit continues the process of converting to the new RTCD
system. It removes the last of the VP8_ENCODER_RTCD struct references.
Change-Id: I2a44f52d7cccf5177e1ca98a028ead570d045395
When running multi-layer (ML) encodes and dynamically
changing coding parameters on the fly (e.g. frame
duration/rate, bandwidths allocated to each layer)
the encoder would not produce sensible output.
In certain cases the rate targeting would be
hideously inaccurate.
These fixes make it possible to change these coding
parameters correctly and to maintain accurate control
of the rate targeting.
I also added the specification of the input timebase
into the test program, vp8_scalable_patterns.c.
Patch 2: Moved declaration to appease MS compiler)
Change-Id: Ic8bb5a16daa924bb64974e740696e040d07ae363
The total_stats, this_frame_stats, and total_left_stats structures
were previously create by a heap allocation, despite being of fixed
size. These structures were allocated and deallocated during
{de,}allocate_compressor_data, which is reinvoked whenever the frame
size changes. Unfortunately, this clobbers the total_stats and
total_left_stats data.
Historically, these were variable size at one time, due to the first
pass motion map, which necessitated their being created by a unique
heap allocation. However, this bug with the total_stats being
clobbered has probably been present since that initial implementation.
These structures are instead moved to be stored within the struct
twopass_rc directly, rather than being heap allocated separately.
Change-Id: I7f9e519e25c58b92969071f0e99fa80307e0682b
Do the test filtering in the existing backup frame buffer instead of
the original. Copy the original data into extra buffer before doing
the filtering. This way there is no need to restore the original
unfiltered frame at the end of level picking process.
This came up in some discussions with Johann. Thanks!
Change-Id: I495f4301d983854673276c34ec0ddf9a9d622122
The example encoder down-samples the input video frames a number of
times with a down-sampling factor, and then encodes and outputs
bitstreams with different resolutions.
Support arbitrary down-sampling factor, and down-sampling factor
can be different for each encoding level.
For example, the encoder can be tested as follows.
1. Configure with multi-resolution encoding enabled:
../libvpx/configure --target=x86-linux-gcc --disable-codecs
--enable-vp8 --enable-runtime_cpu_detect --enable-debug
--disable-install-docs --enable-error-concealment
--enable-multi-res-encoding
2. Run make
3. Encode:
If input video is 1280x720, run:
./vp8_multi_resolution_encoder 1280 720 input.yuv 1.ivf 2.ivf 3.ivf 1
(output: 1.ivf(1280x720); 2.ivf(640x360); 3.ivf(320x180).
The last parameter is set to 1/0 to show/not show PSNR.)
4. Decode:
./simple_decoder 1.ivf 1.yuv
./simple_decoder 2.ivf 2.yuv
./simple_decoder 3.ivf 3.yuv
5. View video:
mplayer 1.yuv -demuxer rawvideo -rawvideo w=1280:h=720 -loop 0 -fps 30
mplayer 2.yuv -demuxer rawvideo -rawvideo w=640:h=360 -loop 0 -fps 30
mplayer 3.yuv -demuxer rawvideo -rawvideo w=320:h=180 -loop 0 -fps 30
The encoding parameters can be modified in vp8_multi_resolution_encoder.c,
for example, target bitrate, frame rate...
Modified API. John helped a lot with that. Thanks!
Change-Id: I03be9a51167eddf94399f92d269599fb3f3d54f5
API was not returning correct partition sizes on arm targets.
The armv5 token packing functions were not storing the information to the
partition size table.
As a fix, have one boolcoder instance allocated for each partition so
that partition sizes are internally available after all partitions
were encoded. This will also allow more flexibility in producing
several partitions in parallel.
Use buffer validation (overflow check) in all ARM bitpacking
functions.
Change-Id: I31c8a11d8a7613676f0ff50928cb2a2ab14fd169
There was an implicit reference frame test order (typically LAST,
GOLD, ARF) in the mode selection logic, but this doesn't provide the
expected results when some reference frames are disabled. For
instance, in real-time mode, the speed selection logic often disables
the ARF modes. So if the user disables the LAST and GOLD frames, the
encoder was always choosing INTRA, when in reality searching the ARF
in this case has the same speed penalty as searching LAST would have
had.
Instead, introduce the notion of a reference frame search order. This
patch preserves the former priorities, so if a frame is disabled, the
other frames bump up a slot to take its place. This patch lays the
groundwork for doing something smarter in the frame test order, for
example considering temporal distance or looking at the frames used by
nearby blocks.
Change-Id: I1199149f8662a408537c653d2c021c7f1d29a700
The calculated frame_rate is a state variable in the codec, and
shouldn't be maintained in the configuration struct. Move it to the
main part of cpi so that it isn't clobbered when the configuration
struct is updated. The initial framerate estimate is moved from the
vp8_cx_iface.c wrapper into the body of init_config() in onyx_if.c, so
that it is only called once and not reset on every call to
vp8_change_config().
Change-Id: I8d9a3d1283330d1ee297d07e9d78d1f2875f2465
In some situations (f.g. error-resilient is turned on), vp8cx_mb
_init_quantizer() was called once per macroblock. Added checks
to avoid calculations when there is no change.
Change-Id: Ie4f0a5ade2202041254990a4e9d5b03bd1ac5aea
check to make sure that cx_data buffer has enough room before
writting to it, prior behavior did not which could result in a crash.
Change-Id: I3fab6f2bc4a96d7c675ea81acd39ece121738b28
Added the ability to create rate-targeted, temporally
scalable, VP8 compatible bitstreams.
The application vp8_scalable_patterns.c demonstrates how
to use this capability. Users can create output bitstreams
containing upto 5 temporally separable streams encoded
as a single VP8 bitstream.
(previously abandoned as:
I92d1483e887adb274d07ce9e567e4d0314881b0a)
Change-Id: I156250a3fe930be57c069d508c41b6a7a4ea8d6a
buffer_level in VP8_COMP and starting_buffer_level, optimal_buffer_level
and maximum_buffer_size in VP8_CONFIG changed from int to int64_t
to avoid potential crash issues for larger target bit rates.
Change-Id: I0d5ab6c8a44c2fef51f30cd8df4bb4b739c5df26
Changes to the selection of Q limits for two pass
and two pass CQ mode.
Allowance made for Mode and motion vector costs.
Some refactoring of common code.
For Derf and YT sets CQ mode average improvement
circa 1% (SSIM and Global PSNR).
Some increased tendency to undershoot even when
user CQ not reached.
Patch2: Removed some test code accidentally merged.
Change-Id: Icf74d13af77437c08602571dc7a97e747cce5066
This change makes sure that no key frame recoding in real-time mode
even if CONFIG_REALTIME_ONLY is not configured.
Change-Id: Ifc34141f3217a6bb63cc087d78b111fadb35eec2
Instead of a single mid GF boost apply a few extra bits to
every other frame. This gives a very small average metrics
improvement on both derf and YT sets.
Also use min GF interval as min KF interval.
Change-Id: Iee238b8cae0ffaed850a5a944ac825cee18da485
This reverts commit b5ea2fbc2c. Further
testing showed noticable keyframe popping in some cases, reverting this
for now to give time for a proper fix.
Conflicts:
vp8/encoder/onyx_if.c
vp8/encoder/ratectrl.c
Change-Id: I159f53d1bf0e24c035754ab3ded8ccfd58fd04af
This patch attempts to improve the handling of CBR streams with
respect to the short term buffering requirements. The "buffer level"
is changed to be an average over the rc buffer, rather than a long
running average. Overshoot is also tracked over the same interval
and the golden frame targets suppressed accordingly to correct for
overly aggressive boosting.
Testing shows that this is fairly consistently positive in one
metric or another -- some clips that show significant decreases
in quality have better buffering characteristics, others show
improvenents in both.
Change-Id: I924c89aa9bdb210271f2e03311e63de3f1f8f920
Allow the encoder to inform the application that the encoded frame will not
be used as a reference.
Change-Id: I90e41962325ef73d44da03327deb340d6f7f4860
In this commit I have added an experimental function
that tests prediction quality either side of a central position
to calculate a suggested boost number for an ARF frame.
The function is passed an offset from the current position and
a number of frames to search forwards and backwards.
It returns a forward, backward and compound boost number.
The new code can be deactivated using #define NEW_BOOST 0
In its current default state the code searches forwards and backwards
from the proposed position of the next alt ref.
The the old code used a boost number calculated by scanning forward
from the previous GF up to the proposed alt ref frame position.
I have also added some code to try and prevent placement of a gf/arf
where there is a brief flash.
Change-Id: I98af789a5181148659f10dd5dd2ff2d4250cd51c
There were many instances in the code of vp8_coef_tokens and
vp8_coef_tokens-1, which was a preprocessor macro despite the naming
convention. Replace these with MAX_ENTROPY_TOKENS and ENTROPY_NODES,
respectively.
Change-Id: I72c4f6c7634c94e1fa066cd511471e5592c748da
With this commit frames can be received partition-by-partition
from the encoder and passed partition-by-partition to the
decoder.
At the encoder-side this makes it easier to split encoded
frames at partition boundaries, useful when packetizing
frames. When VPX_CODEC_USE_OUTPUT_PARTITION is enabled,
several VPX_CODEC_CX_FRAME_PKT packets will be returned
from vpx_codec_get_cx_data(), containing one partition
each. The partition_id (starting at 0) specifies the decoding
order of the partitions. All partitions but the last has
the VPX_FRAME_IS_FRAGMENT flag set.
At the decoder this opens up the possibility of decoding partition
N even though partition N-1 was lost (given that independent
partitioning has been enabled in the encoder) if more info
about the missing parts of the stream is available through
external signaling.
Each partition is passed to the decoder through the
vpx_codec_decode() function, with the data pointer pointing
to the start of the partition, and with data_sz equal to the
size of the partition. Missing partitions can be signaled to
the decoder by setting data != NULL and data_sz = 0. When
all partitions have been given to the decoder "end of data"
should be signaled by calling vpx_codec_decode() with
data = NULL and data_sz = 0.
The first partition is the first partition according to the
VP8 bitstream + the uncompressed data chunk + DCT address
offsets if multiple residual partitions are used.
Change-Id: I5bc0682b9e4112e0db77904755c694c3c7ac6e74
This reverts commit 212f618373.
Further testing shows that the overshoot accumulation/damping is too
aggressive on some clips. Allowing the accumulated overshoot to
decay and limiting to damping to golden frames shows some promise.
But some clips show significant overshoot in the buffer window, so
I think this still needs work.
Change-Id: Ic02a9ca34f55229f9cc04786f4fab54cdc1a3ef5
Some further re-structuring of activity masking code.
Still has various experimental switches.
Supports a metric based on intra encode.
Experimental comparison against a fixed activity target rather
than a frame average, for altering rd and zbin.
Overall the SSIM performance is similar to TT's original
code but there is a much smaller PSNR hit of circa
0.5% instead of 3.2%
Change-Id: I0fd53b2dfb60620b3f74d7415e0b81c1ac58c39a
This patch attempts to reduce the peak bitrate hit by the encoder
when using small buffer windows.
Tested on the CIF set over 200-500kbps using these settings:
--buf-sz=500 --buf-initial-sz=250 --buf-optimal-sz=250 \
--undershoot-pct=100
Two pass encodes were tested at best quality. One pass encodes were
tested only at realtime speed 4:
--rt --cpu-used=-4
The peak datarate (over the specified 500ms window) was measured
for each encode, and averaged together to get metric for
"average peak," computed as SUM(peak)/SUM(target). This patch
reduces the average peak datarate as follows:
One pass:
baseline: 1.29715
this patch: 1.23664
Two pass:
baseline: 1.32702
this patch: 1.37824
This change had a positive effect on our quality metrics as well:
One pass CBR:
Min / Mean / Max (pct)
Average PSNR -0.42 / 2.86 / 27.32
Overall PSNR -0.90 / 2.00 / 17.27
SSIM -0.05 / 3.95 / 37.46
Two pass CBR:
Min / Mean / Max (pct)
Average PSNR -4.47 / 4.35 / 35.99
Overall PSNR -3.40 / 4.18 / 36.46
SSIM -4.56 / 6.98 / 53.67
One pass VBR:
Min / Mean / Max (pct)
Average PSNR -5.21 / 0.01 / 3.30
Overall PSNR -8.10 / -0.38 / 1.21
SSIM -7.38 / -0.11 / 3.17
(note: most values here were close to the mean, there were a few
outliers on files that were very sensitive to golden frame size)
Two pass VBR:
Min / Mean / Max (pct)
Average PSNR 0.00 / 0.00 / 0.00
Overall PSNR 0.00 / 0.00 / 0.00
SSIM 0.00 / 0.00 / 0.00
Neither one pass or two pass CBR mode adheres particularly strictly
to the short term buffer constraints, and two pass is less
consistent, even in the baseline commit. This should be addressed
in a later commit. This likely will hurt the quality numbers, as it
will have to reduce the burstiness of golden frames.
Aside: My work on this commit makes it clear that we need to make
rate control modes "pluggable", where you can easily write a new
one or work on one in isolation.
Change-Id: I1ea9a48f2beedd59891f1288aabf7064956b4716
This patch collects the twopass specific memebers of VP8_COMP into a
dedicated struct. This is a first step towards isolating the two pass
rate control and aids readability by decorating these variables with
the 'twopass.' namespace. This makes it clear to the reader in what
contexts the variable will be valid, and is a hint that a section of
code might be a good candidate to move to firstpass.c in later
refactoring. There likely will be other rate control modes that need
their own specific data as well.
This notation is probably overly verbose in firstpass.c, so an
alternative would be to access this struct through a pointer like
'rc->' instead of 'cpi->firstpass.' in that file. Feel free to make
a review comment to that effect if you prefer.
Change-Id: I0ab8254647cb4b493a77c16b5d236d0d4a94ca4d
This commit restructures the mb activity masking code
to better facilitate experimentation using different metrics
etc. and also allows for adjustment of the zero bin either
for encode only or both the encode and mode selection
stages
It also uses information from the current frame rather than
the previous frame and the default strength has been
reduced.
Change-Id: Id39b19eace37574dc429f25aae810c203709629b
The variable is introduced in commit 2e53e9e53 to make more use of
trellis quantization, but this is no longer necessary after RDMULT
was made adaptive in a number of later commits.
Change-Id: I7420522ec7723f38cf77033466c25afb405d52ae
In NEWMV mode, currently, full search is used as the refining search
after n-step search. By replacing it with an iterative diamond search
of radius 1 largely reduced the computation complexity, but still
maintained the same encoding quality since the refining search is
done for every macroblock instead of only a small precentage of
macroblocks while using full search.
Tests on the test set showed a 3.4% encoding speed increase with none
psnr & ssim loss.
Change-Id: Ife907d7eb9544d15c34f17dc6e4cfd97cb743d41
The existing emulation of posix semaphores on Windows uses SetEvent()
and WaitForSingleObject(), which implements a binary semaphore, not a
counting semaphore as implemented by posix. This causes deadlock when
used with the expected posix semantics. Instead, this patch uses the
CreateSemaphore() and ReleaseSemaphore() calls (introduced in Windows
2000) which have the expected behavior.
This patch also reverts commit eb16f00, which split a semaphore that
was being used with counting semantics into two binary semaphores.
That commit is unnecessary with corrected emulation.
Change-Id: If400771536a27af4b0c3a31aa4c4e9ced89ce6a0
This patch is to fix a rare hang in multi-thread encoder that was
only seen on Windows. Thanks for John's help in debugging the
problem. More test is needed.
Change-Id: Idb11c6d344c2082362a032b34c5a602a1eea62fc
Renamed configure option "enable-psnr" to "enable-internal-stats" to
better reflect the purpose of the option and eliminate the confusion
reported in http://code.google.com/p/webm/issues/detail?id=35
Change-Id: If72df6fdb9f1e33dab1329240ba4d8911d2f1f7a
Combine calc_iframe_target_size, previously only used for forced
keyframes, with calc_auto_iframe_target_size, which handled most
keyframes.
Change-Id: I227051361cf46727caa5cd2b155752d2c9789364
the decision to run the regular or simple loopfilter is made outside the
function and managed with pointers
stop tracking the option in two places. use filter_type exclusively
Change-Id: I39d7b5d1352885efc632c0a94aaf56b72cc2fe15
Remove tot_key_frame_bits and prior_key_frame_size[] as they were
tracked but never used. Remove intra_frame_target, as it was only
used to initialize prior_key_frame_size.
Refactor vp8_adjust_key_frame_context() some to remove unnecessary
calculations.
Change-Id: Icbc2c83d2b90e184be03e6f9679e678f3a4bce8f
This patch cleans up the source buffer storage and copy mechanism to
allow access through a standard push/pop/peek interface. This approach
also avoids an extra copy in the case where the source is not a
multiple of 16, fixing issue #102.
Change-Id: I05808c39f5743625cb4c7af54cc841b9b10fdbd9
in encodframe.c, quant_shift is set to 0 or 1 in vp8cx_invert_quant
only use 8 bits to store this, instead of 16. will allow saving an
xmm register in an updated version of the regular quantize
Change-Id: Ie88c47fe2aff5af0283dab1147fb2791e4b12f90
Detect the number of available cores and limit the thread allocation
accordingly. On decoder side limit the number of threads to the max
number of token partition.
Core detetction works on Windows and
Posix platforms, which define _SC_NPROCESSORS_ONLN or _SC_NPROC_ONLN.
Change-Id: I76cbe37c18d3b8035e508b7a1795577674efc078
In multithreaded mode the loopfilter is running in its own thread (filter level
calculation and frame filtering). Filtering is mostly done in parallel with the
bitstream packing. Before starting the packing the loopfilter level has
to be calculated. Also any needed reference frame copying is done in the
filter thread.
Currently the encoder will create n+1 threads, where n > 1 is the number of
threads specified by application and 1 is the extra filter thread. With n = 1
the encoder runs in single thread mode. There will never be more than n threads
running concurrently.
Change-Id: I4fb29b559a40275d6d3babb8727245c40fba931b
The firstpass motion map consists of an 8-bit flag for
each MB indicating how strongly the firstpass code
believes it should be filtered during the second pass
ARNR filtering.
For long or large format material the motion map can
become extremely large and hamper the operation of
the encoding process.
This change removes the motion map altogether, leaving
the second pass to rely on the magnitude of the motion
compensated error to determine the filter weight to
use for the MB during ARNR filtering.
Tests on the derf set indicate that the effect of this
change is neutral, with some small wins and losses. The
motion map has therefore been removed based on
a cost/benefit evaluation.
Change-Id: I53e07d236f5ce09a6f0c54e7c4ffbb490fb870f6
In some cases where clips have been encoded with
borders (eg. some wide-screen content where there is a
border top and bottom and slide shows containing portrait
format photographs (border left and right)) key frames were
not being correctly detected.
The new code looks to measure cases where a portion of
the image can be coded equally easily using intra or inter
modes and where the resulting error score is also very low.
These "neutral" areas are then discounted in the key frame
detection code.
Change-Id: I00c3e8230772b8213cdc08020e1990cf83b780d8
As mentioned in check-in "Improve motion search in real-time mode",
MV prediction calculation causes speed loss for speed 7 and above.
This change added a flag to turn off this calculation for speed>6
in real-time mode.
Change-Id: I9f4ae5a8bf449222d1784b54e7d315fc8347b2d1
Whe auto keyframe insertion is enabled and conditions are right (scene change)
the encoder can decide to insert a key frame and does a re-encoding. This can
introduce extra latency. In RT mode we do not do the re-encoding of the current
frame but force the next frame to key frame.
Change-Id: I15c175fa845ac4c1a1f18bea3676e154669522a7
Reduce the number of sync points by letting each thread
continue imediatly with a new MB row.
Better multicore scaling, improves performance by 5-20% on ARM multicore.
Change-Id: Ic97e4d1c4886a842c85dd3539a93cb217188ed1b
