Convert JPG to WebP

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JPG's are often used for web sites and email as they are generally smaller file sizes as they are lossy meaning that some image quality is lost when the JPG is compressed and saved. The resultant 'lossy' file means that quality can never be recovered. The JPG format is often used in digital camera memory cards. The JPG file is a great format as it often manages to compress files to 1/10 of the size of the original file which is especially good for saving on bandwidth.

JPG is a popular graphic format, which is characterized by a high degree of compression, which leads to a decrease in image quality. It uses the technology of encoding of smooth color renditions, providing the ability to reduce the amount of data frequently during the recording of the image. Because of the small size it is requested by the owners of websites, allowing you to save the traffic effectively. It is also frequently used in memory cards of digital video cameras. The JPG algorithm is optimally suitable for compressing photographs and pictures, in which realistic scenes with little contrast of colors are present. It is not recommended to use this format for compression of drawings and various kinds of graphics, since a strong contrast between a number of closely located pixels provokes the appearance of visible artifacts.

JPG is a graphical file format for editing still images, it offers a symmetrical compression technique which is processor intensive and time consiming in both compression and decompression. JPEG is a joint standard of the International Telecommunications Union (ITU-T T.81) and the International Organization for Standardization (ISO 10918-1). JPEG involves a lossy compression mechanism using discrete cosine transform (DCT). Compression rates of 100:1 can be achieved, although the loss is noticeable at that level. Compression rates of 10:1 or 20:1 yield little degradation in image quality.

The procedure for compressing the digital images in JPG format is carried out in several stages. First, the photo is transformed into a color space YCbCr, then it is divided into squares to determine the upper range of the color spectrum. Finally, the colors and brightness are coded. JPEG uses a "lossy" compression system and discrete cosine transform technology. The format acts simultaneously as the standard of ISO and the International Telecommunication Union. The file compression ratio is in the range from 10:1 to 100:1. In this case, the reduction in image quality can vary from insignificant to substantial.

The JPEG Committee

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WebP is an image format developed by Google in 2010. The format allows users to save an image in either lossy or lossless format. Google has made bold claims about the compression efficiency of the format stating that it can be up to 34% smaller than the equivalent JPEG or PNG file. Google believes that through the adoption of a more efficient image format, the speed of the web as a whole can be increased due to the volume of images being viewed at any one time across the world.

WebP lossy compression works by a technique of prediction. Each block of pixels are predicted based on other blocks of pixels surrounding it. The difference between the prediction and reality is then encoded. Due to the efficiency of the prediction technique many of the blocks contain a zero difference which results in greater compression and thus a smaller file size. WebP lossless compression works by using parts of the image that have already been analysed to construct other parts of the image.

Google

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