15 Commits

Author SHA1 Message Date
Pascal Massimino
21735e06f7 speed-up trivial one-symbol decoding case for lossless
We now consider 3 special cases:
 * htree-group has only 1 code (no bit is read from bitstream)
 * htree-group has few enough literal symbols, so that all the bit
   codes can fit into a look-up table of less than 64 entries
 * htree-group has a trivial arb literal (not GREEN!), like before

No overall speed change.

Change-Id: I6077fa0b7e5c31a6c67aa8aca859c22cc50ee254
2015-11-16 14:04:51 -08:00
Vikas Arora
f9ced95a9b Optimize lossless decoding for trivial(ARB) codes.
Optimize the decoding for region that have trivial literal codes.
The trivial literal is defined as huffman image with Red, Blue and Alpha
huffman trees with only single code values.
This speeds up lossless decoding by 3%

Change-Id: I0204949917836f74c0eb4ba5a7f4052a4797833b
2014-09-12 09:08:08 -07:00
skal
77d4c7e337 address cosmetic comments from patch #71380
Change-Id: Iaba301b9e77aa4febe0efe1e6016fab42d5589f3
2014-08-28 18:08:00 -07:00
skal
f75dfbf23d Speed up Huffman decoding for lossless
speed-up is ~1.6% for photographic image to 10% for graphical image
(1000 images corpus was sped up by 5.8 %)

Code by akramarz@google.com and jyrki@google.com

Change-Id: Iceb2e50e6cc761b9315a3865d22ec9d19b8011c6
2014-08-28 12:28:04 -07:00
Vikas Arora
9383afd5c7 Reduce number of memory allocations while decoding lossless.
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
2014-05-02 01:01:43 -07:00
James Zern
605a712701 simplify __cplusplus ifdef
drop c_plusplus which is from a quite ancient pre-standard compiler

Change-Id: I9e357b3292a6b52b14c2641ba11f4f872c04b7fb
2013-12-16 20:16:02 -08:00
Jyrki Alakuijala
699d80ea6b Jump-lookup for Huffman coding
speeds up those codes that are not part of the main lookup.
This gives a 10 % speedup for a photographic image.

Change-Id: Ief54b0ad77db790a01314402ad351b40ac9a7be4
2013-06-27 08:59:55 +02:00
skal
24cc307ae3 ~20% faster lossless decoding
We use help from small LUTs for Huffman decoding.

Change-Id: I58db4ecd37282822094519f2aa14cf544beba975
2013-06-20 09:41:29 +02:00
skal
313d853fa9 Speedup for decoding lossless WebP photographs:
use bit_pos instead num_bit to update the bit-reader
37.69 MB/s -> 39.79 MB/s, 5.6 %

Change-Id: Ica476cc3e2fc2db084d6961bea8586b050bb221d
2013-06-18 17:26:52 +02:00
James Zern
d640614d54 update copyright text
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
2013-06-06 23:09:14 -07:00
Pascal Massimino
2fc1301577 harmonize authors as "Name (mail@address)"
Change-Id: I85bfae61a37de75a5ed945a906002de2ef75149f
2012-07-19 16:09:47 -07:00
Urvang Joshi
14757f8ae2 Make sure huffman trees always have valid symbols
- Symbols added to the tree are valid inside HuffmanTreeBuildExplicit().
- In HuffmanTreeBuildImplicit(), make sure 'root_symbol' is
valid in case of a single symbol tree.

Change-Id: I7de5de71ff28f41e2d6228b29ed8dd4a20813e99
2012-05-10 11:40:18 +05:30
Pascal Massimino
8979675bdf harmonize header description
Change-Id: Ie0256794e663b58557e7234f08af3d516071001e
2012-05-04 19:01:06 -07:00
James Zern
fbd82b5a39 types.h: centralize use of stddef.h
for size_t / NULL

Change-Id: If1331d3cf44296ed0ba9e838eae2f5b1bcaeb61b
2012-04-12 17:14:58 -07:00
James Zern
9c67291d67 add utils/huffman.[hc] from experimental
Pulled from the current HEAD (218c32e).
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: Ie57be21bf50ad83808c72aeb5fc706d9954d01d8
2012-04-10 17:31:54 -07:00