If there are too few unique pixel values, the WebP format also provides the option of color indexing transformation. In addition to the general color transformation, a variant is possible in which the green values are deducted from the red and blue values. The green value is kept as it is in the meantime. Here the image is first divided into blocks, before red (R) is transformed based on green (G) and blue (B) based on green and red. The aim of color transform is the decorrelation of the RGB values of each individual pixel. The current pixel value is predicted from already decoded pixels, and only the remaining value is coded. WebP uses 13 different prediction modes, which make use of the fact that neighboring pixels frequently correlate with one another. Animations: The WebP format enables image sequences to be saved.Color profile: The Google format may contain embedded ICC profiles (data sets that describe the color spectrum).Metadata: WebP may include EXIF and XMP metadata, which is typically generated by cameras. Transparency: The 8-bit alpha channel that the WebP format offers can also be used for lossy RGB compression.Compression (lossless): Lossless compression with WebP is based on various techniques that transform the parameters and image data.Compression (lossy): Lossy compression with WebP uses keyframe coding of VP8.The compression features as well as the other central characteristics of the WebP format can be summarized as follows: Thanks to this flexibility, the format is suitable for photos as well as small images and graphics. While both these classic Web formats rely on different compression methods – PNG is lossless and JPEG lossy – WebP allows both options. According to information from Google, images and graphics in WebP format are around 30 per cent smaller than PNG or JPEG files with the same image quality. WebP has always served the purpose of reducing images on the Web to as small a file size as possible.
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