Zip and rar are both lossless compression; the main difference between zip and rar is in terms of compression rate, compression speed and security. Lossless compression refers to the use of statistical redundancy of data for compression, which can completely restore the original data Without causing any distortion, the compressed files currently on the market including zip, rar and other formats are lossless compression.
The operating environment of this tutorial: Windows 10 system, DELL G3 computer.
Both ZIP and RAR are lossless compression
The difference between the two is mainly in compression ratio, compression speed and security Sexually. In terms of compression rate, RAR is higher than ZIP; in terms of compression speed, ZIP is faster than RAR; in terms of security, RAR non-open source is more secure and reliable. The following is a detailed description:
Currently, compressed files in ZIP, RAR and other formats on the market are lossless compression, and the files after normal decompression are the same no matter which compression tool is used;
The main difference between ZIP and RAR is the compression algorithm. The former is an open source free tool, and the latter is a non-open source paid tool. In comparison, RAR has a higher compression rate, stronger security, and more powerful compression functions (with functions such as locking compressed files to prevent modification); while ZIP’s only advantage is that it has fast compression speed, but it is easy to be cracked.
Lossless compression format
The lossless compression format uses the statistical redundancy of data for compression, and can completely restore the original data without It does not cause any distortion, but the compression rate is theoretically limited by the statistical redundancy of the data, generally 2:1 to 5:1. This type of method is widely used in text data, programs and image data in special applications (such as fingerprint images , medical images, etc.) compression.
Due to the limitation of compression ratio, it is impossible to solve all the problems of storage and transmission of images and digital videos using only lossless compression methods. Frequently used lossless compression methods include Shannon-Fano coding, Huffman coding, and run-length ( Run-length) coding, LZW (Lempel-Ziv-Welch) coding and arithmetic coding, etc.
The so-called lossless compression format, as the name suggests, is an audio format that compresses sound signals without any loss. Common formats such as MP3 and WMA are lossy compression formats. Compared with the source WAV file, they all have a considerable degree of signal loss, which is the fundamental reason why they can achieve a compression rate of 10%. The lossless compression format is like using compression software such as Zip or RAR to compress audio signals. The resulting compression format is restored to a WAV file, which is exactly the same as the source WAV file! But if you use Zip or RAR to compress WAV files, you must decompress the compressed package before it can be played. The lossless compression format can be played directly through the playback software in real time, and it is used exactly the same as MP3 and other lossy formats. All in all, the lossless compression format is a format that can reduce the size of WAV files without sacrificing any audio signal.
For more related knowledge, please visit theFAQcolumn!
The above is the detailed content of Which one is lossless compression, zip or rar?. For more information, please follow other related articles on the PHP Chinese website!