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:
http://www.corp.google.com/~yaowu/no_crawl/t8x8/cif_cost8x8only.html
(avg psnr:.14% glb psnr: .17% ssim: .20%)
http://www.corp.google.com/~yaowu/no_crawl/t8x8/hd_cost8x8only.html
(avg psnr:.17% glb psnr: .18% ssim: .58%)
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.
Change-Id: If9b7868b75357c66541f511e5ee78e4d2d4929a4
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
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
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
This commit has a few minor fixes to the 8x8 trellis quant, so to
make it work regardless if extend_qrange is enabled or not. It also
borrowed adaptive RDMULT constants from 4x4 trellis that was missed
in the 8x8 trellis quant.
Change-Id: I60d7769071f102c699b5084597e62bca87a1f759
This commit added scaling factors to 8x8 transform, quant, dequant and
inverse transform pipeline to make 8x8 transform to work when configed
with enable-extend_qrange. This commit also disabled the trellis-quant
when extend_qrange is configured.
Change-Id: Icfb3192e4746f70a4bb35ad18b7b47705b657e52
extend_qrange introduces a different scaling factor, this commit takes
the scaling difference into account for reset 2nd order coefficients.
Change-Id: Ie58bca9f52698fa759e3f88da2aa4d82630fa91a
The 8x8 forward transform makes use of floating operations, therefore
requires emms call to reset mmx registers to correct state. Without
the resets, the 8x8 forward transform results are indefinite on win32
platform.
Change-Id: Ib5b71c3213e10b8a04fe776adf885f3714e7deb1
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
As discovered in path 10 of Change Ia12acd2f, reset 2nd order coeffs
without reset of above and left coding context may have introduced
problem that causes encoder/decoder mismatching. This commit added
update to coding context when the 2nd coefficients are cleared.
In addition, this commit also introduced early breakout in the checks
to speed up when coefficients are too significant to be cleared.
Change-Id: I85322a432b11e8af85001525d1e9dc218f9a0bd6
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
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
With this fix, the experimental branch now builds and encodes correctly
with the following two configure options respectively:
--enable-experimental --enable-t8x8
--enable-experimental
Change-Id: I3147c33c503fe713a85fd371e4f1a974805778bf
I got this idea from Pascal (Thanks). Before encoding a macroblock,
copy it to a 16x16 buffer, and then read source data from there
instead. This will help keep the source data in cache, and help
with the performance.
Change-Id: Id05f4cb601299150511d59dcba0ae62c49b5b757
Code cleanup. The build inter predictor functions are
redundantly checking the mode_info_context for either
INTRA_FRAME or SPLITMV.
Change-Id: I4d58c3a5192a4c2cec5c24ab1caf608bf13aebfb
A large number of functions were defined with external linkage, even
though they were only used from within one file. This patch changes
their linkage to static and removes the vp8_ prefix from their names,
which should make it more obvious to the reader that the function is
contained within the current translation unit. Functions that were
not referenced were removed.
These symbols were identified by:
$ nm -A libvpx.a | sort -k3 | uniq -c -f2 | grep ' [A-Z] ' \
| sort | grep '^ *1 '
Change-Id: I59609f58ab65312012c047036ae1e0634f795779
Prior to this change, VP8 min quantizer is 4, which caps the
highest quality around 51DB. This experimental change extends
the min quantizer to 1, removes the cap and allows the highest
quality to be around ~73DB, consistent with the fdct/idct round trip
error. To test this change, at configure time use options:
--enable-experimental --enable-extend_qrange
The following is a brief log of changes in each of the patch sets
patch set 1:
In this commit, the quantization/dequantization constants are kept
unchanged, instead scaling factor 4 is rolled into fdct/idct.
Fixed Q0 encoding tests on mobile:
Before: 9560.567kbps Overall PSNR:50.255DB VPXSSIM:98.288
Now: 18035.774kbps Overall PSNR:73.022DB VPXSSIM:99.991
patch set 2:
regenerated dc/ac quantizer lookup tables based on the scaling
factor rolled in the fdct/idct. Also slightly extended the range
towards the high quantizer end.
patch set 3:
slightly tweaked the quantizer tables and generated bits_per_mb
table based on Paul's suggestions.
patch set 4:
fix a typo in idct, re-calculated tables relating active max Q
to active min Q
patch set 5:
added rdmult lookup table based on Q
patch set 6:
fix rdmult scale: dct coefficient has scaled up by 4
patch set 7:
make transform coefficients to be within 16bits
patch set 8:
normalize 2nd order quantizers
patch set 9:
fix mis-spellings
patch set 10:
change the configure script and macros to allow experimental code
to be enabled at configure time with --enable-extend_qrange
patch set 11:
rebase for merge
Change-Id: Ib50641ddd44aba2a52ed890222c309faa31cc59c
This patch adds a weighting factor on RDMULT for UV blocks. The change
has an overall gain about 0.5% based on ssim, between 0.1 and 0.2% by
psnr numbers.
Change-Id: I97781b077ce3bb7e34241b03268491917e8d1d72
This intends to correct the tendency that VP8 aggressively favors rate
on intra coded frames. Experiments tested different numbers in [0, 1]
and found 9/16 overall provided about 2-4% gains for all-intra coded
clips based on vpx-ssim metric. The impact on regular encoded clips
is much smaller but positive overall. Overall impact on psnr is also
positive even though very small.
Change-Id: If808553aaaa87fdd44691f9787820ac9856d9f8a
ARM NEON has a platform specific version of vp8_recon16x16mb, though
it's just a stub to extract the various parameters from the
MACROBLOCKD struct and pass them to vp8_recon16x16mb_neon(). Using
that function's prototype directly will be a better long term solution,
but it's quite an invasive change.
Change-Id: I04273149e2ade34749e2d09e7edb0c396e1dd620
Most of the code that actually uses these matrices indexes them as
if they were a single contiguous array, and coverity produces
reports about the resulting accesses that overflow the static
bounds of the first row.
This is perfectly legal in C, but converting them to actual [16]
arrays should eliminate the report, and removes a good deal of
extraneous indexing and address operators from the code.
Change-Id: Ibda479e2232b3e51f9edf3b355b8640520fdbf23
when a subsequent frame is encoded as an alt reference frame, it is
unlikely that any mb in current frame will be used as reference for
future frames, so we can enable quantization optimization even when
the RD constant is slightly rate-biased. The change has an overall
benefit between 0.1% to 0.2% bit savings on the test sets based on
vpxssim scores.
Change-Id: I9aa7bc5cd573ea84e3ee655d2834c18c4460ceea
This patch moves the scattered updates to the mb skip state
(mode_info_context->mbmi.mb_skip_coeff) to vp8_tokenize_mb. Recent
changes to the quantizer exposed a bug where if a macroblock
could be coded as a skip but isn't, the encoder would run the
loopfilter but the decoder wouldn't, causing a reference buffer
mismatch.
The loopfilter is controlled by a flag called dc_diff. The decoder
looks at the number of decoded coefficients when setting this flag.
The encoder sets this flag based on the skip state, since any
skippable macroblock should be transmitted as a skip. The coefficient
optimization pass (vp8_optimize_b()) could change the coefficients
such that a block that was not a skip becomes one. The encoder was
not updating the skip state in this situation for intra coded blocks.
The underlying issue predates it, but this bug was recently triggered
by enabling trellis quantization on the Y2 block in commit dcd29e3,
and by changing the quantizer range control in commit 305be4e.
Change-Id: I5cce5da0dbc2d22f7d79ee48149f01e868a64802
This uses MB variance to change the RDO weight for mode decision
and quantization.
Activity is normalized against the average for the frame, which is
currently tracked using feed-forward statistics.
This could also be used to adjust the quantizer for the entire
frame, but that requires more extensive rate control changes.
This does not yet attempt to adapt the quantizer within the frame,
but the signaling cost means that will likely only be useful at
very high rates.
Change-Id: I26cd7c755cac3ff33cfe0688b1da50b2b87b9c93
Experimented with different value for Y2_RD_MULT ranging f[1, 32],
without adapting the value to MB coding mode/frame type/Q value,
4 works out best among all values, providing overall 0.1% coding
gain on the test set.
Change-Id: I6b2583a8aa5db5e7e5c65c646301909c0c58f876
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
The main reason for the change was to reduce cycles in the token
decoder. (~1.5% gain for 32 bit) This layout should be more
cache friendly.
As a result of this change, the encoder had to be updated.
Change-Id: Id5e804169d8889da0378b3a519ac04dabd28c837
Note: dixie uses a similar layout
These copies occurred for each macroblock in the encoder and decoder.
Thetemp MB_MODE_INFO mbmi was removed from MACROBLOCKD. As a result,
a large number compile errors had to be fixed.
Change-Id: I4cf0ffae3ce244f6db04a4c217d52dd256382cf3
Replace the exponential search for optimal rounding during
quantization with a linear Viterbi trellis and enable it
by default when using --best.
Right now this operates on top of the output of the adaptive
zero-bin quantizer in vp8_regular_quantize_b() and gives a small
gain.
It can be tested as a replacement for that quantizer by
enabling the call to vp8_strict_quantize_b(), which uses
normal rounding and no zero bin offset.
Ultimately, the quantizer will have to become a function of lambda
in order to take advantage of activity masking, since there is
limited ability to change the quantization factor itself.
However, currently vp8_strict_quantize_b() plus the trellis
quantizer (which is lambda-dependent) loses to
vp8_regular_quantize_b() alone (which is not) on my test clip.
Patch Set 3:
Fix an issue related to the cost evaluation of successor
states when a coefficient is reduced to zero. With this
issue fixed, now the trellis search almost exactly matches
the exponential search.
Patch Set 2:
Overall, the goal of this patch set is to make "trellis"
search to produce encodings that match the exponential
search version. There are three main differences between
Patch Set 2 and 1:
a. Patch set 1 did not properly account for the scale of
2nd order error, so patch set 2 disable it all together
for 2nd blocks.
b. Patch set 1 was not consistent on when to enable the
the quantization optimization. Patch set 2 restore the
condition to be consistent.
c. Patch set 1 checks quantized level L-1, and L for any
input coefficient was quantized to L. Patch set 2 limits
the candidate coefficient to those that were rounded up
to L. It is worth noting here that a strategy to check
L and L+1 for coefficients that were truncated down to L
might work.
(a and b get trellis quant to basically match the exponential
search on all mid/low rate encodings on cif set, without
a, b, trellis quant can hurt the psnr by 0.2 to .3db at
200kbps for some cif clips)
(c gets trellis quant to match the exponential search
to match at Q0 encoding, without c, trellis quant can be
1.5 to 2db lower for encodings with fixed Q at 0 on most
derf cif clips)
Change-Id: Ib1a043b665d75fbf00cb0257b7c18e90eebab95e
The new fdct lowers the round trip sum squared error for a
4x4 block ~0.12. or ~0.008/pixel. For reference, the old
matrix multiply version has average round trip error 1.46
for a 4x4 block.
Thanks to "derf" for his suggestions and references.
Change-Id: I5559d1e81d333b319404ab16b336b739f87afc79
