Saturation was done on input coeff, not quantized one.
This saturation is not absolutely needed: output of FTransformWHT
is in range [-16320, 16321]. At quality 100, max quantization steps is 8,
so the maximal range used by QuantizeBlock() is [-2040, 2040].
But there's some extra bias (mtx->bias_[] and mtx->sharpen_[]) so
it's better to leave this saturation check for now.
addresses issue #145
Change-Id: I4b14f71cdc80c46f9eaadb2a4e8e03d396879d28
* merge cost calculation functions (BitsEntropy() and HuffmanCost())
* have HistogramAdd() specialized into separate functions
* use threshold to bail-out early
* revamp code a bit
* also: save memory by freeing free(histogram_image)
Change-Id: I8ee5d2cfa1462d5d6ea6361f5c89925a3720ef55
* VP8L shouldn't have an alpha chunk
* expect an animation to only contain frames, not a mix of image chunks
* enforce ANIM/ANMF order
* expect a full frame in a complete file
Change-Id: I953a8b6058f9bc00f1d042635548f158abdf6fce
subdirectories with more than one target can have the install targets
run in parallel with make -jN. group the shared headers in one place to
produce a common install target.
Change-Id: I1f3aa338a8ee6d681de1e5d0b2c6244d2c3d5451
Reported to eventually be 4% on ARM
(see https://code.google.com/p/webp/issues/detail?id=134 for details)
We might activate it selectively later...
Output values is not bitwise the same as the LUT-based
version, but difference is only +/-1 at max.
Change-Id: I1cc790ff4459885ed2ae2e72f31c5f3740095f07
this allows DLLs to be built under mingw and sets up a more obvious
dependency in the shared objects
Change-Id: I33e8a6132a16ca49563492438a1b3b74be9ed6a1
expands to e.g., -lpthread/-pthread, etc. if --enable-threading is used
and additional libs/flags are required
Change-Id: I8e8a7b44450bee32ddc58097e1e309d972b1092a
This is required for WebP lossy+Alpha images, where Alpha channel is taking
60-70% of the compression (CPU) cycles.
Also evaluated on 1000 PNG corpus and overall compression speed
is 15-40% better for lossy (PNG+Alpha) compression.
The pure lossless compression numbers are almost same (or little
better) with this change.
Change-Id: I9e5ae7372ed6227a9a5b64cd9cff84c747195a57
using token-buffer (that is: slightly more memory. O(output_size))
This change is ON by default. To return to previous behaviour, use
'cwebp -low_memory' or set config.low_memory to true.
Side-effect of this new mode: it forces 1 partition only (which was
default anyway), and makes some statistics about the bitstream
no longer available. cwebp will no longer report 'intra4-coeffs', etc.
This mode also doesn't work (yet) with multi-pass, and -low_memory
is currently forced for multi-pass.
also: reversed the flag: USE_TOKEN_BUFFER -> DISABLE_TOKEN_BUFFER
also: fixed the kAverageBytesPerMB estimate
Change-Id: I4ea80382038d6df4309663e0cb7bd88d9bca9cf1
When a ANMF/FRGM chunk size (read from file) is smaller than ANMF/FRGM header
size (which is constant and implicit), the parser should report an error.
Change-Id: I91d71889937f5133a97f1e83d5254cb2d7f37028
broken since:
ad25032 Merge "multi-threaded alpha encoding for lossy"
this produced an error due to an empty VP8TBuffer struct.
Change-Id: I640809d07d20092c1d660e2b59b58a62a12e4371
Also tweak the code for single image and fragmented image cases, so that
dmux->num_frames_ is always correct.
Change-Id: I31e6904222e4d96a54a0d8c8aa73d43b7a9094e7
new option: 'cwebp -mt ...'
new config flag: config.thread_level
(allowed thread_level are 0 or 1 for now. Maybe more later...)
If -mt is activated (and WEBP_USE_THREAD is used for compile), the alpha-compression
will be done in parallel to RGB coding for lossy. Can save quite a bit of latency...
Has no effect for lossless encoding.
Change-Id: I769d0bf90e7380cf99344ad62cd77277f4df5a46
