Solution for checking Cyclic Redundancy of audio and video files

Problem Analysis

Cyclic Redundancy check (CRC) is a data transmission error checking function. It computes the polynomials of the data, attaches the obtained results to the back of the frame, and performs similar operations on the receiving device.AlgorithmTo ensure the correctness and integrity of data transmission. If CRC verification fails, the system copies the data to the hard disk repeatedly and falls into an endless loop, leading to the failure of the replication process.

Solution

Note that some data is actually copied to the hard disk in the above process, but some data CRC cannot be checked out, Windows Copy command cannot skip the data and continue to execute. When the operation cannot be completed, the system will delete the data that has been copied to the hard disk, resulting in a complete copy failure. This problem can be solved if the error data can be skipped during replication. When we download files from the Internet, the most common download tool is flashget. Flashget can divide a file into several parts for simultaneous download or multiple download processes.

Procedure

First, we create a local site through IIS (Internet Information Service. If this component has not been installed, you need to add/delete it in "Control Panel>Program→ Add/delete Windows components ", click components, select IIS, and click" next "to insert the installation disc to complete the installation.

Next, create a virtual directory with the address corresponding to the directory where your audio and video files are located. Take iis5.0 in Windows 2000 as an example. The procedure for creating a virtual directory is as follows: (see the attachment for the instance)

1. Start IIS in "Start Menu> program> Management Tools;

2. Right-click "Default web site" and choose "New> virtual directory ";

3. Enter the directory name, which is assumed to be yyfiles;

4. Enter the directory path (the path should be the directory where your audio and video files are located). If you do not need to change the path, you can continue to "Next.

Start flashget and create a download task. In the URL bar, enter "http: // localhost/yyfiles/kill with a knife. Avi ".

In this way, you can start multi-threaded download. When one of the processes reaches a certain level of progress, the error data will gradually decrease to zero, but the other parts will continue as usual. When the remaining parts are completed, the remaining parts are divided into several parts for download. In this way, all data except the error data is downloaded to the hard disk.

Finally, go to the download directory and "use a knife to kill. Avi. JC!" the file !" The copy process is completed after the name is changed to "knife killing. Avi. Although this is complicated, it saves my audio and video files and does not need to be downloaded again. We recommend that you use the preceding Processing Method for audio and video files. Do not use this method for important files or software.