Question: What Exactly Is ‘Codec’? Why Would I Ever Need It?
“Codec” is a technical name for “compression/decompression”. It also stands for “compressor/decompressor” and “code/decode”. All of these variations mean the same thing: a codec is a computer program that both shrinks large movie files, and makes them playable on your computer. Codec programs are required for your media player to play your downloaded music and movies.
Why do we need codecs?
ANS: Because video and music files are large, they become difficult to transfer across the Internet quickly. To help speed up downloads, mathematical “codecs” were built to encode (“shrink”) a signal for transmission and then decode it for viewing or editing. Without codecs, downloads would take three to five times longer than they do now.
Is there only one codec I need?
ANS: Sadly, there are hundreds of codecs being used on the Internet, and you will need combinations that specifically play your files.
There are codecs for audio and video compression, for streaming media over the Internet, videoconferencing, playing mp3’s, speech, or screen capture. To make matters more confusing, some people who share their files on the Net choose to use very obscure codecs to shrink their files. This makes it very frustrating for users who download these files, but do not know which codecs to get to play these files. If you are a regular downloader, you will probably need ten to twelve codecs to play your music and movies.
Read more at netforbeginners.about.com