* make VP8LPrefetchBits() safe wrt past-EOS reads
* set 'BitReader::bits_" to a safe shifting value upon EOS
no visible performance difference on x86
Change-Id: I0a4177928cfa81d5dfc9054b36a686eaa1bf8c65
ReadSymbol() finishes with a VP8LSetBitPos() call only and could miss an eos_ during the decode loop.
Things are faster because of inlining too.
Change-Id: I2d2a275f38834ba005bc767d45c5de72d032103e
eos_ needs to be set only when superfluous bits have actually
been requested.
Earlier, we were assuming pre-mature end-of-stream to be an error.
Now, more precisely, we mark error when we have encountered end-of-stream *and*
we attempt to read more bits after that.
This handles cases where image data requires no bits to be read
Change-Id: I628e2c39c64f10c443fb51f86b1f5919cc9fd299
also reduce the load size from 64 to 32 bits as the top 32 bits are
being shifted away in the operation.
the change is neutral speed-wise on x86_64 as is the change in load size
on x86, but it gives a slight improvement on 32-bit arm.
x86 is improved ~13%, 32-bit arm ~3.7%
aarch64 is untested but will likely benefit as well.
Change-Id: Ibcb02a70f46f2651105d7ab571afe352673bef48
* remove LEFT/RIGHT_JUSTIFY distinction. It's all RIGHT_JUSTIFY now.
* simplify VP8GetSigned(), and add some masking branch-less code. Much
faster on ARM (~13% speed-up). 8% on x86-64, 5% on MacBook.
* split critical implementation into separate bit_reader_inl.h file that
is only included where needed (vp8.c / tree.c / bit_reader.c)
* bumped BITS value from 16 to 24 for x86-32b too, since it's a bit faster.
Change-Id: If41ca1da3e5c3dadacf2379d1ba419b151e7fce8
gcc was generating very complex code, one for each case of br->len_ values!
also, pretty-fy the mask constants
Change-Id: If62b1e8266f3fe5334517305113038d2ea8a6b42
Sometimes, we can write 18bit or more at time, and it would
overflow the 32bit accumulator.
Also clarified the num-bits limitations (and exposed
VP8L_MAX_NUM_BIT_READ in bit_reader.h)
fixes http://code.google.com/p/webp/issues/detail?id=200
Seems a bit faster (use of local fields for bits_ / used_)
also: added the __QNX__ bswap while at it.
Change-Id: I876db93a931db15b083cf1d838c70105effa7167
When remapping buffer, br->eos_ was wrongly being set to true for
certain
images.
Also, refactored the end-of-stream detection as a function.
Reported in http://crbug.com/364830
Change-Id: I716ce082ef2b505fe24246b9c14912d8e97b5d84
Earlier we were only testing for bit_pos == LBITS. But this is not
sufficient,
as bit_pos can jump from < LBITS to > LBITS.
This was resulting in some bit-stream truncation errors not being
caught.
Note: Not a security bug though, as br->pos wasn't incremented in such
cases
and so we weren't reading beyond the buffer.
Change-Id: Idadcdcbc6a5713f8fac3470f907fa37a63074836
rather than symlink the webm/vpx terms, use the same header as libvpx to
reference in-tree files
based on the discussion in:
https://codereview.chromium.org/12771026/
Change-Id: Ia3067ecddefaa7ee01550136e00f7b3f086d4af4
Simplify and re-organize the VP8L bit-reader functions
(e.g.: the 40-bit look-ahead code was helping much)
Speed-up with LBITS=64, on arm7-a:
=> before:
./dwebp_justify_24_neon -v bryce_ll.webp
Time to decode picture: 11.393s
File bryce_ll.webp can be decoded (dimensions: 11158 x 2156).
...
=> after (LBITS=64): Time to decode picture: 9.953s
making the VP8L bit-reader in 32 bit mode is going to be
harder (because we need to be able to read two symbols
at a time, each with max length 15 bits)
Change-Id: I89746fb103b87b5e2fd40a3208a6fbc584b88297
* each with their own decoder instances.
* Refactor the incremental buffer-update code a lot.
* remove br_offset_ for VP8LDecoder along the way
* make VP8GetHeaders() be used only for VP8, not VP8L bitstream
* remove VP8LInitDecoder()
* rename VP8LBitReaderResize() to VP8LBitReaderSetBuffer()
(cherry picked from commit 5529a2e6d47212a721ca4ab003215f97bd88ebb4)
Change-Id: I58f0b8abe1ef31c8b0e1a6175d2d86b863793ead
Pulled from the parent of the current version (5529a2e^).
The history of this and related files is a bit entangled so rather
trying to split the changes and introduce some noise in master's history
we'll start with a fresh snapshot.
The file progression is still available in the experimental branch.
Change-Id: I6dae97fc381cd6c1d1640c4c565b2084a41ec955
