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What this article shares with you is about the difference between lossy compression and lossless compression. I think it is very practical, so I share it with you. I hope you can get something after reading this article. Let's take a look at it with the editor.

Differences: 1, lossless compression can be completely restored; lossy compression restore can not be the same as the original file, there is a certain amount of loss. 2. The compression ratio of lossless compression generally ranges from "200" to "5:1", while the compression ratio of lossy compression can reach "200" or more.

Both lossy compression and lossless compression belong to compression technology, but no matter what kind of technical model is adopted, the essential contents of both are the same, that is, the repetition and redundancy of data information are effectively reduced by some special coding method, so as to achieve the purpose of data compression. Its basic principle is that without affecting the basic use of the file, only some "key points" in the original data are retained, and the repeated and redundant information in the data is removed, so as to achieve the purpose of compression.

The difference between lossy compression and lossless compression

1. The difference in reducibility

Lossless compression can be completely restored; lossy compression can not be restored with the same as the original file, there is a certain amount of loss.

2. The difference in compression ratio

Lossless compression ratio is limited by the theoretical redundancy of data statistics, which generally ranges from 2:1 to 5:1.

Lossy compression takes advantage of the fact that human beings are insensitive to some frequency components of images or sound waves, allowing the loss of certain information in the compression process. Although the original data can not be completely recovered, the impact of the loss on the understanding of the original image is reduced, but in exchange for a much larger compression ratio up to 200.1 or more.

3. Differences in compressed file format

Mp3, divX, Xvid, jpeg, rm, rmvb, wma, wmv and other formats are lossy compression.

Lossless compression formats commonly used are APE, FLAC, TAK, WavPack, TTA and so on.

4. The difference in compression principle

Two basic mechanisms of lossy compression:

One is lossy transform coding and decoding, which first samples the image or sound, cuts it into small blocks, transforms it to a new space, quantizes it, and then encodes the quantized value with entropy.

The other is predictive coding and decoding, in which the previous data and the subsequently decoded data are used to predict the current sound sampling or image frame, the error between the predicted data and the actual data, and other reproduced predicted information to quantify and encode.

The principles of lossless compression include run length coding, Huffman coding and arithmetic coding.

5. Differences in the field of application

Lossy compression is widely used in voice, image and video data compression.

Limited by the compression ratio, lossless compression is only used for the compression of text data, programs and image data in special applications (such as fingerprint images, medical images, etc.), but the prospect of lossless compression format is undoubtedly bright. With the passage of time, various factors that restrict lossless format will be gradually eliminated.

For example, with the continuous increase of hard disk capacity, mechanical hard disk 1TB has become the mainstream, and solid-state hard disk 200GB will also be popular.

The problem that lossless format takes up a lot of space will no longer be a problem, and faster decoding chips will also be developed. It is believed that more and more hard disk Walkman will support lossless format. In the near future, even the capacity of flash Walkman will be calculated by TB, in order to pursue higher sound quality, lossless compression format will be paid more and more attention.

The above is the difference between lossy compression and lossless compression. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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