Licensing options for this format begin with FME Desktop Professional Edition.
The Google WebP Reader/Writer module provides FME with access to data in the WebP format.
It supports both lossy and lossless compression. WebP lossless images are smaller in size than PNG files, and lossy images are smaller in size than JPEG files at a similar quality.
Overview
The WebP format was developed by Google for storing images on the web.
The information below is included on the Google Developers website: http://developers.google.com/speed/webp/. Please see this page for additional information.
WebP provides lossless and lossy compression for images on the web. WebP lossless images are smaller in size compared to PNG images. WebP lossy images are smaller in size compared to JPEG images at equivalent SSIM index.
WebP supports lossless transparency (also known as alpha channel). Transparency is also supported with lossy compression.
Lossy WebP compression uses predictive coding to encode an image, the same methodology used by the VP8 video codec to compress keyframes in videos. Predictive coding uses the values in neighboring blocks of pixels to predict the values in a block, and then encodes only the difference (residual) between the actual values and the prediction.
The residuals typically contain many zero values, which can be compressed much more effectively. The residuals are then transformed, quantized and entropy-coded as usual. WebP also uses variable block sizes.
Lossless WebP compression uses already seen image fragments in order to exactly reconstruct new pixels. It can also use a local palette if no interesting match is found. This palette is continuously updated to re-use recent colors. This compression mode is named "VP8L" and shares some common features with the so-called LZ77 compression algorithm.
Reader Overview
FME considers a single WebP file to be a dataset.
Writer Overview
FME considers a dataset to be a folder name. The feature type of each dataset is the filename.
FME Raster Features
FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data. The topics below describe how FME processes raster data.
WebP files can only be written with square pixel dimensions.
WebP only supports rasters with a Red8, a Green8, a Blue8 band, and optionally an Alpha8 band.