The luminance needs to be pre- and post- multiplied by
the alpha value in case of rescaling, for proper averaging.
Also:
- removed util/alpha_processing and moved it to dsp/
- removed WebPInitPremultiply() which was mostly useless
and merged it with the new function WebPInitAlphaProcessing()
Change-Id: If089cefd4ec53f6880a791c476fb1c7f7c5a8e60
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
MALLOC_FAIL_AT flag can be used to set-up a pre-determined failure
point during malloc calls. The counter value is retrieved using
getenv().
Example usage: export MALLOC_FAIL_AT=37 && cwebp input.png
will make 'cwebp' report a memory allocation error the 37th time
malloc() or calloc() is called.
MALLOC_MEM_LIMIT can be used similarly to prevent allocating more
than a given amount of memory. This is usually less convenient to
use than MALLOC_FAIL_AT since one has to know in advance the typical
memory size allocated.
Both these flags are meant to be used for debugging only!
Also: added a 'total_mem_allocated' to record the overall memory allocated
Change-Id: I9d408095ee7d76acba0f3a31b1276fc36478720a
This change reduces the number of calls to WebPSafeMalloc from 200 to
100. The overall memory consumption is down 3% for Lenna image.
Change-Id: I1b351a1f61abf2634c035ef1ccb34050b7876bdd
Some tracing code is activated by PRINT_MEM_INFO flag.
For debugging only! (not thread-safe, and slow).
Change-Id: I282c623c960f97d474a35b600981b761ef89ace9
* merged the two HistogramAdd/AddEval() into a single call
(with detection of special case when b==out)
* added a SSE2 variant
* harmonize the histogram type to 'uint32_t' instead
of just 'int'. This has a lot of ripples on signatures.
* 1-2% faster
Change-Id: I10299ff300f36cdbca5a560df1ae4d4df149d306
Reduce calls to Malloc (WebPSafeMalloc/WebPSafeCalloc) for:
- Building HashChain data-structure used in creating the backward references.
- Creating Backward references for LZ77 or RLE coding.
- Creating Huffman tree for encoding the image.
For the above mentioned code-paths, allocate memory once and re-use it
subsequently.
Reduce the foorprint of VP8LHistogram struct by changing the Struct
field 'literal_' from an array of constant size to dynamically allocated
buffer based on the input parameter cache_bits.
Initialize BitWriter buffer corresponding to 16bpp (2*W*H).
There are some hard-files that are compressed at 12 bpp or more. The
realloc is costly and can be avoided for most of the WebP lossless
images by allocating some extra memory at the encoder initializaiton.
Change-Id: I1ea8cf60df727b8eb41547901f376c9a585e6095
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
.set at - Indicates that macro expansions may clobber
the assembler temporary ($at or $28) register.
Some macros may not be expanded without this
and will generate an error message if noat
is in effect.
"at" also added to the clobber list.
Change-Id: I67feebbd9f2944fc7f26c28496e49e1e2348529d
there's still some malloc/free in the external example
This is an encoder API change because of the introduction
of WebPMemoryWriterClear() for symmetry reasons.
The MemoryWriter object should probably go in examples/ instead
of being in the main lib, though.
mux_types.h stil contain some inlined free()/malloc() that are
harder to remove (we need to put them in the libwebputils lib
and make sure link is ok). Left as a TODO for now.
Also: WebPDecodeRGB*() function are still returning a pointer
that needs to be free()'d. We should call WebPSafeFree() on
these, but it means exposing the whole mechanism. TODO(later).
Change-Id: Iad2c9060f7fa6040e3ba489c8b07f4caadfab77b
Separate the C version from the MIPS32 version and have run-time
initialization during RescalerInit()
Change-Id: I93cfa5691c073a099fe62eda1333ad2bb749915b
* simplify the endian logic
* remove the need for memset()
* write 16 or 32 at a time (likely aligned)
Makes the code a bit faster on ARM (~1%)
Change-Id: I650bc5654e8d0b0454318b7a78206b301c5f6c2c
Even at high quality setting, the U/V quantizer step is limited
to 4 which can lead to banding on gradient.
This option allows to selectively apply some randomness to
potentially flattened-out U/V blocks and attenuate the banding.
This option is off by default in 'dwebp', but set to -dither 50
by default in 'vwebp'.
Note: depending on the number of blocks selectively dithered,
we can have up to a 10% slow-down in decoding speed it seems.
Change-Id: Icc2446007f33ddacb60b3a80a9e63f2d5ad162de
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
in_bits is const. Trying to apply bswap on it, one gets the error message:
error: read-only variable 'in_bits' used as 'asm' output
Change-Id: I0bef494b822c83d8ea87b1938b0e486d94de4742
speeds up those codes that are not part of the main lookup.
This gives a 10 % speedup for a photographic image.
Change-Id: Ief54b0ad77db790a01314402ad351b40ac9a7be4
