This commit added pre/post scaling for first half of fDCT16x16 to
reduce error, by simulation of 100,000 blocks for random inputs,
the average sse reduced from 2.1/block to 0.0498/block.
also enabled tests for 16x16 fDCT and iDCT
Change-Id: Id2a95f0464c6dd4118797d456237ae90274c0f02
This patch alters the balance of context between the
coefficient bands (reflecting the position of coefficients
within a transform blocks) and the energy of the previous
token (or tokens) within a block.
In this case the number of coefficient bands is reduced
but more previous token energy bands are supported.
Some initial rebalancing of the default tables has been
by running multiple derf clips at multiple data rates using
the ENTOPY_STATS macro. Further balancing needs to be
done using larger image formatsd especially in regard to
the bigger transform sizes which are not as well represented
in encodings of smaller image formats.
Change-Id: If9736e95c391e711b04aef6393d26f60f36e1f8a
The commit added a final rounding choice for 8x8 forward dct to get
rid of a sign bias at DC position and improve the accuracry in term
of round trip error for 8x8 fDCT/iDCT.
This commit also enabled forward 8x8 dct test.
Change-Id: Ib67f99b0a24d513e230c7812bc04569d472fdc50
The issue that potentially broke the encoding process was due to the fact
that the length of token link is calculated from the total number of tokens
coded, while it is possible, in high bit-rate setting, this length is
greater than the buffer length initially assigned to the cpi->tok.
This patch increases the initially allocated buffer length assigned to
cpi->tok from
(mb_rows * mb_cols * 24 * 16) to (mb_rows * mb_cols * (1 + 24 * 16)).
It resolves the buffer overflow problem.
Change-Id: I8661a8d39ea0a3c24303e3f71a170787a1d5b1df
Removing redundant 'extern' keywords and parentheses, fixing indentation,
making variable names lower case, using short expressions x *= c
instead of x = x * c, minor code simplifications.
Change-Id: If6a25fcf306d1db26e90d27e3c24a32735c607de
1. changed 4x4 test name to Vp9Fdct4x4Test to be consistent
2. remove forward 8x8 dct test code from idct8x8_test.cc
3. temporarily disable other forward dct tests to allow fdct work in
progress
Change-Id: I566aeed9c7c34da5a206190aa7d0e847a4008b36
The over quant code was added in VP8 post
bitstream freeze to allow compression to lower
data rates
In VP9 the real qualtizer range has been greatly
extended anyway.
Change-Id: I5d384fa5e9a83ef75a3df34ee30627bd21901526
This patch includes 4x4, 8x8, and 16x16 forward butterfly ADST/DCT
hybrid transform. The kernel of 4x4 ADST is sin((2k+1)*(n+1)/(2N+1)).
The kernel of 8x8/16x16 ADST is of the form sin((2k+1)*(2n+1)/4N).
Change-Id: I8f1ab3843ce32eb287ab766f92e0611e1c5cb4c1
Allows the user to specify whether decode errors should be fatal or not.
Also makes mismatches optionally fatal.
Change-Id: I58cff4a82f3d42f5653b91cf348a7f669377e632
Removing redundant 'extern' keyword from function declarations and making
function arguments lower case.
Change-Id: Idae9a2183b067f2b6c85ad84738d275e8bbff9d9
Refactors the switchable filter search in the rd loop to
improve encode speed.
Uses a piecewise approximation to a closed form expression to estimate
rd cost for a Laplacian source with a given variance and quantization
step-size.
About 40% encode time reduction is achieved.
Results (on a feb 12 baseline) show a slight drop:
derf: -0.019%
yt: +0.010%
std-hd: -0.162%
hd: -0.050%
Change-Id: Ie861badf5bba1e3b1052e29a0ef1b7e256edbcd0
The issue that potentially broke the encoding process was due to the fact
that the length of token link is calculated from the total number of tokens
coded, while it is possible, in high bit-rate setting, this length is
greater than the buffer length initially assigned to the cpi->tok.
This patch increases the initially allocated buffer length assigned to
cpi->tok from
(mb_rows * mb_cols * 24 * 16) to (mb_rows * mb_cols * (1 + 24 * 16)).
It resolves the buffer overflow problem.
Change-Id: I8661a8d39ea0a3c24303e3f71a170787a1d5b1df
- Using multiplication and shifting instead of division in
intra prediction.
- Maximum absolute difference is 1 for division statements
in d45, d27, d63 prediction modes. However, errors can
cumulate for large block sizes when using already predicted
values.
- Maximum number of non-matching result values in loops using
division are:
4x4 0/16
8x8 0/64
16x16 10/256
32x32 13/1024
64x64 122/4096
Overall PSNR
derf: 0.005
yt: -0.022
std-hd: 0.021
hd: -0.006
Change-Id: I3979a02eb6351636442c1af1e23d6c4e6ec1d01d
The issue was caused by a out-of-order merge, which leads to wrong
functions are called at lossless mode.
Change-Id: If157729abab62954c729e0377e7f53edb7db22ca
