| commit | df4ec90a2befb79ed45cf8810e8ac93da7a47297 | [log] [tgz] |
|---|---|---|
| author | Yannis Guyon <yguyon@google.com> | Tue Nov 24 10:29:15 2020 |
| committer | Yannis Guyon <yguyon@google.com> | Tue Nov 24 10:35:02 2020 |
| tree | edbd461542ac0789f6a616485febc0d5342e039c | |
| parent | 94de1c5c6d04cbadfea873a353f0aee3fbe02e84 [diff] |
libwebp2: Upstream sync Squashed commits: c3cebf85ddb58c1a430154015b1c9a559d96c42d wp2: Upstream sync 612a70edd2fff8994767f3c3d0c47e9a0e0850fb wp2: ProgressHook float -> double precision 5c030c02449db6ef6c362fe98bcf4114e53b28f1 wp2: uint32_t kMaxChunkSize fitting in 29 bits 1581703aceabc89120bbd124f2410d772da4e521 Merge "quality parameter: refine the doc in header" f72125b0950d2c2c390677d7a1f750bd9f0549e3 quality parameter: refine the doc in header 9d35c105c6308c72693ec168dcc9521686c8bc2b Merge "move Premultiply() function to the SSE block" 9bf5e4e7998a4aadf8910f0e84f21de6d9450d55 vwp2: misc fixes 48ad8212275730228937d2cffc1eed5338aacd53 make chunk size be uint64_t instead of size_t 6b91ab48d3a743ddab6b0f38178641e8779924d6 move Premultiply() function to the SSE block Change-Id: Iebd6a681b81f448724fc8d8fc8bde74c4befae5e Reviewed-on: https://chromium-review.googlesource.com/c/codecs/libwebp2/+/2557043 Tested-by: Yannis Guyon <yguyon@google.com> Verified-Ubuntu: Yannis Guyon <yguyon@google.com> Reviewed-by: Yannis Guyon <yguyon@google.com>
WebP 2 is the successor of the WebP image format, currently in development. It is not ready for general use, and the format is not finalized so changes to the library can break compatibility with images encoded with previous versions. USE AT YOU OWN RISK!
This package contains the library that can be used in other programs to encode or decode Webp 2 images, as well as command line tools.
See http://developers.google.com/speed/webp for the first version of WebP .
The WebP 2 experimental codec is mostly pushing the features of WebP further in terms of compression efficiency. The new features (like 10b HDR support) are kept minimal. The axis of experimentation are:
The use cases remain mostly the same as WebP: transfer over the wire, faster web, smaller apps, better user experience... WebP 2 is primarily tuned for the typical content available on the Web and Mobile apps: medium-range dimensions, transparency, short animations, thumbnails.
WebP2 is currently only partially optimized and, roughly speaking 5x slower than WebP for lossy compression. It still compresses 2x faster than AVIF, but takes 3x more time to decompress. The goal is to reach decompression speed parity.
A compiler (e.g., gcc 6+, clang 7+ or Microsoft Visual Studio 2017+ are recommended) and CMake.
On a Debian-like system the following should install everything you need for a minimal build:
$ sudo apt-get install build-essential cmake
$ mkdir build && cd build $ cmake .. $ make -j
Configuration options:
WP2_ENABLE_SIMD: enable any SIMD optimization.WP2_ENABLE_BITTRACE: enable tracing.For additional options see:
$ cmake .. -LH
cwp2 is a tool to encode images in webp2.
Usage:
$ cwp2 in_file [options] [-o out_file]
Example for a single image:
$ cwp2 -q 70 input.png -o output.wp2
Example for an animation, with list of frames and durations in ms:
$ cwp2 -q 70 -f frame1.png 10 frame2.png 20 frame3.png 5 -o output.wp2
Important options:
| Flag | Default value | Description |
|---|---|---|
-o <string> | output file path | |
-q <float> | 75 | image quality factor [0=lossy : 100=lossless]* |
-alpha_q <float> | 100 | alpha quality factor [0=lossy : 100=lossless]* |
-effort <int> | 5 | compression effort [0=fast : 9=slower/better] |
-f [<str> <int>] | create an animation (alternate image, duration) |
* The quality factor range corresponds to:
| Quality factor | Meaning |
|---|---|
| 0 | Lossy compression, smallest file size and worst quality |
| ... | Lossy compression |
| 95 | Lossy compression, biggest file size and best quality |
| 96 | Near-lossless compression (maximum preprocessing) |
| ... | Near-lossless compression |
| 99 | Near-lossless compression (minimum preprocessing) |
| 100 | Lossless compression |
Use cwp2 -h to see a full list of available options.
dwp2 is a tool to decode webp2 images.
Usage:
$ dwp2 in_file [options] [-o out_file]
Use dwp2 -h to see a full list of available options.
vwp2 is a visual inspection and debugging tool. You need OpenGL and GLUT to build it.
To open any image (jpeg, png, etc.) then compress it in WebP 2 and view the result:
$ vwp2 in_file...
vwp2 takes most of the same flags as cwp2, e.g. -q for quality. Encoding parameters can also be changed dynamically in the tool using key bidings.
Press h to a list of key bindings.
Use the top left menu or press v and shift+v to cycle between views.
Press i to show or hide info (note this hides the menu).
To view an already compressed file, use:
$ vwp2 -d path/to/image.wp2
rd_curve is a command-line tool for compressing images at multiple quality levels using different codecs (webp2, webp, jpeg, av1) to create rate-distortion curves (rd curves). An rd curve is a plot of distortion (difference between source and encoded image) vs bits per pixel, for different quality settings.
$ rd_curve [options] input_file
rd_curve takes most of the same flags as cwp2, e.g. -q for quality, -effort, and so on.
By default, only the webp2 codec is used. Use -webp, -jpeg or -av1 flags to add other codecs.
By default, results are printed as plain text on standard output.
With the -html flag, rd_curve outputs an html file. It also saves compressed images (turns on the -save option). Use the -save_folder option to set the directory where images are saved.
$ rd_curve input.png -webp -jpeg -av1 -html -save_folder $(pwd) > myfile.html
get_disto computes the difference between two images (typically the compressed file and the original file)
$ get_disto [options] compressed_file orig_file
get_disto outputs in order:
Encoding functions are available in the header src/wp2/encode.h.
#include "imageio/image_dec.h" #include "src/wp2/base.h" #include "src/wp2/encode.h" WP2::ArgbBuffer input_buffer; WP2Status status = WP2::ReadImage("path/to/image.png", &input_buffer); if (status != WP2_STATUS_OK) { /* handle error */ } WP2::EncoderConfig config; config.quality = 70; WP2::MemoryWriter writer; status = WP2::Encode(input_buffer, &writer, config); if (status != WP2_STATUS_OK) { /* handle error */ } // do something with writer.mem_
#include "imageio/image_dec.h" #include "src/wp2/base.h" #include "src/wp2/encode.h" WP2::ArgbBuffer frame1, frame2; WP2Status status = WP2::ReadImage("path/to/frame1.png", &frame1); if (status != WP2_STATUS_OK) { /* handle error */ } status = WP2::ReadImage("path/to/frame2.png", &frame2); if (status != WP2_STATUS_OK) { /* handle error */ } WP2::AnimationEncoder encoder; status = encoder.AddFrame(frame1, /*duration_ms=*/100); if (status != WP2_STATUS_OK) { /* handle error */ } status = encoder.AddFrame(frame2, /*duration_ms=*/50); if (status != WP2_STATUS_OK) { /* handle error */ } WP2::EncoderConfig config; config.quality = 70; WP2::MemoryWriter writer; status = encoder.Encode(&writer, config, /*loop_count=*/1); if (status != WP2_STATUS_OK) { /* handle error */ } // do something with writer.mem_
Decoding functions are available in the header src/wp2/decode.h.
This is mainly just one function to call:
#include "src/wp2/base.h" #include "src/wp2/decode.h" const std::string data = ... WP2::ArgbBuffer output_buffer; WP2Status status = WP2::Decode(data, &output_buffer);
If the file is a WebP 2 animation, output_buffer will contain the first frame.
Please have a look at the file src/wp2/decode.h for further details.
To decode all the frames of an animation, the more advanced Decoder API can be used. See tests/test_decoder_api.cc for common use cases.
WP2::ArrayDecoder decoder(data, data_size); uint32_t duration_ms; while (decoder.ReadFrame(&duration_ms)) { // A frame is ready. Use or copy its 'duration_ms' and 'decoder.GetPixels()'. } if (decoder.GetStatus() != WP2_STATUS_OK) { /* error */ }
If you want to start decoding before all the data is available, you can use the Decoder API. Use an WP2::ArrayDecoder if the data is stored in an array that progressively gets larger, with old bytes still available as new bytes come in. Use a WP2::StreamDecoder if data is streamed, with old bytes no longer available as new bytes come in. You can also subclass WP2::CustomDecoder to fit your needs. See tests/test_decoder_api.cc for common use cases.
Below is an example with WP2::StreamDecoder.
WP2::StreamDecoder decoder; while (/*additional data is available in some 'new_data[]' buffer*/) { decoder.AppendInput(new_data, new_data_size); while (decoder.ReadFrame()) { // ReadFrame() returns true when an entire frame is available // (a still image is considered as a single-frame animation). // The canvas is stored in GetPixels() till the next call to ReadFrame(). // Use the whole GetPixels(). } if (decoder.Failed()) break; if (!decoder.GetDecodedArea().IsEmpty()) { // Use the partially GetDecodedArea() of GetPixels(). } } if (decoder.GetStatus() != WP2_STATUS_OK) { /* error */ }
Please report all bugs to the issue tracker: https://bugs.chromium.org/p/webp2
See CONTRIBUTING.md for details on how to submit patches.
One of the easiest ways to contribute is to report cases with compression artifacts or surprising output size. These ‘bad cases’ are very useful to help improve the compression library!
Please use the tracker to report such issues, making sure to include:
the version or revision used (using “git rev-parse HEAD” for instance)
the version of the compiler used (if you compiled your own version)
the problematic source image (will only be used for debugging and discarded afterward!)
the exact command line to use to reproduce the issue
the output file, if applicable.
Code must follow the Google C++ style guide unless local style differs.
const is used for variables everywhere possible, including for pointers in function declarations. Input parameters use const references.
void DoSomething(const Type1& const input, Type2* const out)
Do not use C++ exceptions.
Do not use std containers in the main library, e.g. no std::vector/set/map (but they can be used in tests). For vectors, use WP2::Vector instead.
Use uint32_t for sizes, width, height, loop indices, etc.
Most functions should return a WP2Status
A part of testing support is built using Google Test. To enable it the WP2_ENABLE_TESTS cmake variable must be turned on at cmake generation time (ON by default), and the GTEST_SOURCE_DIR cmake variable must be set to the path of the Google Test source directory (../googletest by default):
$ git clone https://github.com/google/googletest.git path/to/googletest $ cmake path/to/wp2 -DWP2_ENABLE_TESTS=ON -DGTEST_SOURCE_DIR=path/to/googletest
To run the tests you can use ctest after the build:
$ make
$ ctest