webp/README.mux

119 lines
3.7 KiB
Plaintext
Raw Normal View History

 __ __ ____ ____ ____ __ __ _ __ __
/ \\/ \/ _ \/ _ \/ _ \/ \ \/ \___/_ / _\
\ / __/ _ \ __/ / / (_/ /__
\__\__/\_____/_____/__/ \__//_/\_____/__/___/
Description:
============
WebP Mux: library to create a WebP container object for features like
color profile, XMP metadata, animation & tiling. A reference command line
tool 'webpmux' and WebP container specification 'doc/webp-container-spec.txt'
are also provided in this package.
WebP Mux tool:
==============
The examples/ directory contains a tool (webpmux) for manipulating WebP
files. The webpmux tool can be used to create a WebP container file and to
extract or strip relevant data from the container file.
A list of options is available using the -help command line flag:
> webpmux -help
Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT
webpmux -set SET_OPTIONS INPUT -o OUTPUT
webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT
webpmux -tile TILE_OPTIONS [-tile...] -o OUTPUT
webpmux -frame FRAME_OPTIONS [-frame...] -loop LOOP_COUNT -o OUTPUT
webpmux -info INPUT
webpmux [-h|-help]
GET_OPTIONS:
Extract relevant data.
icc Get ICCP Color profile.
xmp Get XMP metadata.
tile n Get nth tile.
frame n Get nth frame.
SET_OPTIONS:
Set color profile/metadata.
icc Set ICC Color profile.
xmp Set XMP metadata.
STRIP_OPTIONS:
Strip color profile/metadata.
icc Strip ICCP color profile.
xmp Strip XMP metadata.
TILE_OPTIONS(i):
Create tiled image.
file_i +xi+yi
where: 'file_i' is the i'th tile (webp format),
'xi','yi' specify the image offset for this tile.
FRAME_OPTIONS(i):
Create animation.
file_i +xi+yi+di
where: 'file_i' is the i'th animation frame (webp format),
'xi','yi' specify the image offset for this frame.
'di' is the pause duration before next frame.
INPUT & OUTPUT are in webp format.
WebP Mux API:
==============
The WebP Mux API contains methods for adding data to and reading data from
WebPMux (a WebP container object). This API currently supports XMP metadata,
color profile, animation & tiling. Other features will be added in subsequent
releases.
Example#1 (pseudo code): Creating a WebPMux object with image data, color
profile & XMP metadata.
int copy_data = 0;
WebPMux* mux = WebPMuxNew();
// ... (Prepare image data).
WebPMuxSetImage(mux, image_data, image_data_size, alpha_data, alpha_size,
copy_data);
// ... (Prepare ICCP color profile data).
WebPMuxSetColorProfile(mux, icc_data, icc_data_size, copy_data);
// ... (Prepare XMP metadata).
WebPMuxSetMetadata(mux, xmp_data, xmp_data_size, copy_data);
// Get data from mux in WebP RIFF format.
WebPMuxAssemble(mux, &output_data, &output_data_size);
WebPMuxDelete(mux);
// ... (Consume output_data; e.g. write output_data to file).
free(output_data);
Example#2 (pseudo code): Get image & color profile data from a WebP file.
int copy_data = 0;
// ... (Read data from file).
WebPMux* mux = WebPMuxCreate(data, data_size, copy_data);
WebPMuxGetImage(mux, &image, &alpha);
// ... (Consume image; e.g. call WebPDecode() to decode the data).
WebPMuxGetColorProfile(mux, &icc_chunkdata);
// ... (Consume icc_chunkdata).
WebPMuxDelete(mux);
free(data);
For detailed Mux API reference, please refer to the header file (src/webp/mux.h)
Bugs:
=====
Please report all bugs to our issue tracker:
http://code.google.com/p/webp/issues
Patches welcome! See this page to get started:
http://www.webmproject.org/code/contribute/submitting-patches/
Discuss:
========
Email: webp-discuss@webmproject.org
Web: http://groups.google.com/a/webmproject.org/group/webp-discuss