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authorLiang Qi <liang.qi@theqtcompany.com>2016-03-09 10:22:13 +0100
committerLiang Qi <liang.qi@theqtcompany.com>2016-03-11 20:05:19 +0000
commitb114e552211456fbde3ff6ca2da21cbc8d1e90e2 (patch)
tree9c033ea7bcc9cc7314eaa8aff57356b2ae301257 /src/3rdparty/libwebp/README
parent1d4f24820c0fff474d524e006d715e13e409a4b8 (diff)
downloadqtimageformats-b114e552211456fbde3ff6ca2da21cbc8d1e90e2.tar.gz
libwebp: update to 0.5.0
This commit imports libwebp 0.5.0, including AUTHORS, COPYING, ChangeLog, NEWS, PATENTS, README and src directories. In src, only includes header and source files. The patches required to build it in Qt will follow in separate commit(s). Change-Id: I96b4961ba63c75cc7fbab158c36a0f403f254c14 Reviewed-by: aavit <eirik.aavitsland@theqtcompany.com>
Diffstat (limited to 'src/3rdparty/libwebp/README')
-rw-r--r--src/3rdparty/libwebp/README50
1 files changed, 46 insertions, 4 deletions
diff --git a/src/3rdparty/libwebp/README b/src/3rdparty/libwebp/README
index dd50185..381b927 100644
--- a/src/3rdparty/libwebp/README
+++ b/src/3rdparty/libwebp/README
@@ -4,7 +4,7 @@
\__\__/\____/\_____/__/ ____ ___
/ _/ / \ \ / _ \/ _/
/ \_/ / / \ \ __/ \__
- \____/____/\_____/_____/____/v0.4.4
+ \____/____/\_____/_____/____/v0.5.0
Description:
============
@@ -15,7 +15,8 @@ as well as the command line tools 'cwebp' and 'dwebp'.
See http://developers.google.com/speed/webp
-Latest sources are available from http://www.webmproject.org/code/
+The latest source tree is available at
+https://chromium.googlesource.com/webm/libwebp
It is released under the same license as the WebM project.
See http://www.webmproject.org/license/software/ or the
@@ -53,6 +54,12 @@ Please refer to makefile.unix for additional details and customizations.
Using autoconf tools:
---------------------
+Prerequisites:
+A compiler (e.g., gcc), make, autoconf, automake, libtool.
+On a Debian-like system the following should install everything you need for a
+minimal build:
+$ sudo apt-get install gcc make autoconf automake libtool
+
When building from git sources, you will need to run autogen.sh to generate the
configure script.
@@ -152,6 +159,8 @@ Options:
default, photo, picture,
drawing, icon, text
-preset must come first, as it overwrites other parameters
+ -z <int> ............... activates lossless preset with given
+ level in [0:fast, ..., 9:slowest]
-m <int> ............... compression method (0=fast, 6=slowest)
-segments <int> ........ number of segments to use (1..4)
@@ -179,13 +188,15 @@ Options:
-alpha_method <int> .... transparency-compression method (0..1)
-alpha_filter <string> . predictive filtering for alpha plane,
one of: none, fast (default) or best
- -alpha_cleanup ......... clean RGB values in transparent area
+ -exact ................. preserve RGB values in transparent area
-blend_alpha <hex> ..... blend colors against background color
expressed as RGB values written in
hexadecimal, e.g. 0xc0e0d0 for red=0xc0
green=0xe0 and blue=0xd0
-noalpha ............... discard any transparency information
-lossless .............. encode image losslessly
+ -near_lossless <int> ... use near-lossless image
+ preprocessing (0..100=off)
-hint <string> ......... specify image characteristics hint,
one of: photo, picture or graph
@@ -268,13 +279,16 @@ Use following options to convert into alternate image formats:
-nofilter .... disable in-loop filtering
-nodither .... disable dithering
-dither <d> .. dithering strength (in 0..100)
+ -alpha_dither use alpha-plane dithering if needed
-mt .......... use multi-threading
-crop <x> <y> <w> <h> ... crop output with the given rectangle
- -scale <w> <h> .......... scale the output (*after* any cropping)
+ -resize <w> <h> ......... scale the output (*after* any cropping)
+ -flip ........ flip the output vertically
-alpha ....... only save the alpha plane
-incremental . use incremental decoding (useful for tests)
-h ....... this help message
-v ....... verbose (e.g. print encoding/decoding times)
+ -quiet ....... quiet mode, don't print anything
-noasm ....... disable all assembly optimizations
Visualization tool:
@@ -294,6 +308,7 @@ Options are:
-nofancy ..... don't use the fancy YUV420 upscaler
-nofilter .... disable in-loop filtering
-dither <int> dithering strength (0..100), default=50
+ -noalphadither disable alpha plane dithering
-mt .......... use multi-threading
-info ........ print info
-h ....... this help message
@@ -344,6 +359,10 @@ Options:
or lossless compression heuristically
-q <float> ............. quality factor (0:small..100:big)
-m <int> ............... compression method (0=fast, 6=slowest)
+ -min_size .............. minimize output size (default:off)
+ lossless compression by default; can be
+ combined with -q, -m, -lossy or -mixed
+ options
-kmin <int> ............ min distance between key frames
-kmax <int> ............ max distance between key frames
-f <int> ............... filter strength (0=off..100)
@@ -366,6 +385,29 @@ or using autoconf:
$ ./configure --enable-everything
$ make
+Comparison of animated images:
+==============================
+Test utility anim_diff under examples/ can be used to compare two animated
+images (each can be GIF or WebP).
+
+Usage: anim_diff <image1> <image2> [options]
+
+Options:
+ -dump_frames <folder> dump decoded frames in PAM format
+ -min_psnr <float> ... minimum per-frame PSNR
+ -raw_comparison ..... if this flag is not used, RGB is
+ premultiplied before comparison
+
+Building:
+---------
+With the libgif development files and a C++ compiler installed, anim_diff can
+be built using makefile.unix:
+$ make -f makefile.unix examples/anim_diff
+
+or using autoconf:
+$ ./configure --enable-everything
+$ make
+
Encoding API:
=============