The importance of compressing files transmitted across the Internet
Introduction
Files are often transmitted across the Internet. When we send files such as films or music files as attachments, the bigger they are, the longer they take to transmit. For this reason, we often 'compress' files before sending them, to make them smaller. This keeps transmission times down. Also, in the past, you would have to download an entire file for a film or song before you could watch or listen to them. Now, we expect to be able to 'stream' files. That means we want to be able to start watching or listening to something before the whole file has been downloaded. for this reason as well, compressing files is important.
Compression and codecs
We know that a streamed song or film is one where you listen or watch as it is downloaded from the Internet, as opposed to downloading and saving the whole file first and then playing it. As the first few seconds of a streamed file are downloaded, they are put into a special storage area called a 'buffer' and then playing starts. While that part of the file is played, more of it is being downloaded and buffered. If the files are too large, however, then you can't download it quickly enough for it to be buffered and played. The file stops for a little while, to give your computer the time to download more of the song before playing can resume.
To get round this problem, they are usually 'compressed'. That means that the raw sound or movie file has a maths formula applied to it (called a 'codec', short for coder / decoder) so that the raw file gets squashed or 'compressed'. The file then becomes much smaller in size so it can be downloaded and streamed more quickly.
Another use of file compression is when we want to send someone large files across the Internet. When we send any large files, it takes time to send them. It also takes up storage space when they receive the files. If we compress them first, we reduce the overall size of the file. That means the compressed file takes less time to be sent and takes up less storage space when it is received. Many people commonly talk about 'zipping up some files'. By this, they mean using some file compression software to make them smaller.
You can compress files using a number of applications, many of which are free to use for individuals, although some applications you have to pay for. One well-known application is called 7-zip. Another is called Winzip.