The quality of an image was measured using SSIM. We set all other parameters to their default We used cjpeg and djpeg toĮncode and decode JPEG image. We used theĭefault encoding and decoding parameters of these tools.Ĭjpeg and djpeg are command-line tools that are part of the libjpeg We usedĬwebp and dwebp to encode and decode the WebP images. We used identify to extract the width and height information of anĪre command-line tools that are part of the libwebp library we We used convert to convert between PNG and PPM formats. Identify and convert are command-line tools that are part of The command line tools used for this experiment are: Only publicly availableĬommand line tools are used to keep the experiments reasonably reproductibleįor others. Large collection of PNG images that were crawled from the web.Įach experiment consists of running a set of commands. Obtained from publicly accessible standard test image suites as well as a The data sets for the experiments consist of PNG images. These plots show the rate-distortion trade off for WebP and JPEG. Second case, we analyze SSIM vs bits per pixel (bpp) plots for WebP and JPEG. JPEG images and then compare the file sizes of WebP and JPEG images. Particular, we generate WebP images of same quality (as per SSIM index) as the In the first case, we study theĪdditional compression achieved by WebP at the same quality level of JPEG. SSIM is considered to be a better visual quality We use in this study Structural Similarity orįor this study.

Based on feedback from the community, we conduct theĮxperiments on PNG images including images available in a few standard test JPEG is a lossy compression format and introducesĬompression artifacts to the source.

Our earlier comparative study of WebP focused onĮvaluating a large number of images and was conducted on JPEG sources that Image compression achieved by WebP and JPEG. The goal is to run a set ofĮasily repeatable experiments using publicly available tools and compare the The new encoder that we released in libwebp. We do a comparative evaluation of WebP and JPEG image compression based on

File size reducer png