Why do some files be pressed so small, while others are almost unchanged when compressed?

WinRar can compress files, but not all files can be compressed, because some files are themselves a compressed file format.

If you use WinRar to compress an already compressed file, the file size will certainly not change much. Such as the commonA jpg image file is an image file format that has been compressed if it is compressed to the maximum.

compression, then what compression software do you use?

When handling it, its size will not be reduced while maintaining its original quality.

File compression is divided into two types: lossy compression and lossless compression, our commonly used winrar, winzip are lossless compression, the basic principle is the same, simply put, the duplicate data in the file is represented in a more concise way, for example, there are 1000 letters A in a file, then this will occupy 1kb of data space, if the compression algorithm can be represented by 1000a, then it only needs 5 bytes of data space, compression ratio.

Up to 200 times.

From this point of view, a compression ratio of 1000x or even higher is achievable, but requires the source file.

There must be enough duplicate data. However, this is not the case with the files we usually use, so the file compression ratio is usually less than 10 times, and if a software claims to be able to produce this ultra-high compression ratio for any file, then it must be deceptive.

Many ** files on the Internet are only 300MB or 400MB, but after decompression, it can reach 2GB or even more, you may wonder, why you use WinRAR to compress the same file, there is no such compression effect? In fact, this is because these files are compressed with a variety of different compression software, the best compression software for compressing audio compresses the audio file, and the best compression software for compressing animation. The parameters selected during compression are also optimal, which ensures that the final compressed file is minimal.

That needs to see if your file has compressed space,A**and**put together, there is no space, naturally it will not get smaller,Compressed files are sometimes for the convenience of uploading,You can compress them separately。

The reason is that the "minimum" or "best" item is not selected when compressing the interface, and the interface of the commonly used compression software has two modes of "fastest" and "best", select "best" (some are called the smallest), and then check the "create a solid compressed file", you can compress the file small, the following takes "2345 good book trillion pressure " as an example, and gives a guess about the method of compressing to the minimum:

Material required: 2345 good pressure.

1. As shown below, the original ** is 943KB size, right-click it**, and click "Add to Compressed File" in the menu.

2. After opening the compression window, click "Switch to Classic Mode" in the lower right corner.

3. Use "7z" in the compression file format (if the state hand is using winrar to compress the file, then the format should be in the rar format), use "best" in the compression method, and check the right "create solid compressed file" (only 7z can create a solid compressed file in the good pressure software, and winrar only can be in rar format), click "OK".

Fourth, the final effect is as shown below, the size of the compressed compressed package is reduced to 770kb.

It's not high, so the size basically hasn't changed after compression, and the compression ratio of documents like excel or word is relatively high. For example, if the ** file is in JPEG image format, then WinRAR will not be able to compress well with its compression ratio.

Only the general is only 93%, that is to say, 1000k **, the maximum compressed file is 930k, almost no smaller.

Compressed files are processed with or without loss by algorithms to retain the most file information and reduce the file size. The basic principle of compressing a file is to find duplicate bytes within a file and create an identical one"Dictionaries"Wen Xi Zheng piece, and with a ** representation, so that you can achieve the purpose of shrinking the file software.

The reason for this problem is that the state stupid "minimum" or "best" option is not selected when compressing the interface, and it can be checked to 2345.

For example, perform the following steps:

1. First of all, open the file that needs to be compressed, and you can see that the size of the original ** is 943kb. Right-click the **, and then click Add to Compressed File in the menu. , as shown in the image below, and proceed to the next step.

2. Secondly, in the pop-up window, click the "Switch to Classic Mode" option in the lower right corner, as shown in the image below of the file spine, and then proceed to the next step.

3. Next, in the pop-up window, compress the file format.

Select 7z, select Best as the compression method, then select Create Solid Capacity Compression File on the right, click OK, as shown in the following figure, and then proceed to the next step.

4. Finally, you can see the compressed package.

The size is reduced to 770kb, as shown in the figure below. In this way, the problem is solved.

Hello, it is a pleasure to serve you and give you the following answers: The reasons for this are as follows:1

The file is already compressed: Some files are already compressed, such as jpeg, png, ***, mp4, etc., so if you compress it again, the size of the file will not change. 2.

Insufficient compression: Sometimes, the compression software you may use is not compressed enough, and there is still a lot of room to compress, so the file size does not change. 3.

Improper settings of the compression software: Sometimes, the compression software that users may use is not set up properly, such as setting different levels of compression, so that the file size does not change. Workaround:

1.Use files of other formats: If the file itself is compressed, then you can try to use files of other formats such as txt, doc, pdf, etc., which may have a higher degree of compression for better compression.

2.Change the compression level: You can try changing the settings of the compression software, such as turning the compression level up, so that you can get better compression.

3.Use other compression software: You can try to use other compression software, such as Winrar, 7-Zip, etc., which may have a higher degree of compression and can get better compression results.

Personal experience: When compressing files, you should pay attention to checking the format of the file, as well as choosing the appropriate compression software and adjusting the corresponding settings, so as to obtain better compression results.

Find out for you now.

The reason for this problem is that the "minimum" or "best" option is not selected when compressing the interface, check it, take 2345 good pressure as an example, the specific operation steps are as follows: 1. First of all, open the file that needs to be compressed, and you can see that the size of the original ** is 943kb. Right-click the **, and then click Add to Compressed File in the menu.

Then move on to the next step. 2. Secondly, in the pop-up window, click on the "Switch to Classic Mode" option in the bottom right corner and proceed to the next step. 3. Then, in the pop-up window, select "7z" for the compression file type, select [Best] for the compression method, then select "Create Solid Compression File" on the right side, click "OK", and then enter the next step.

4. Finally, you can see that the size of the compressed package is reduced to 770kb, and you can reduce it by following the above steps.

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Movies are all compressed, for example, the current popular encoding methods in China are rmvb, xvid, h264, the bandwidth utilization of these movies themselves is already very high, and you will not compress much with any compression software.

The same is true for jpg, which is also a lossy compression format.

7z is better than zip, but as I said above, you can't hold it down much even with 7z.

Usually we will record or receive, and the file size is too large, which will directly affect our sending and uploading, and especially occupy memory. At this time, we need to compress the **, but many people have no change in compression, so today I will teach you how to compress the **.