Codec is an algorithm, usually installed as a program on a server or placed w/in a hardware piece, that is utilized to change voice (in the case of Voice over Internet Protocol or VoIP) signals to digital data to be broadcasted through the Internet or other network throughout a VoIP call.

The term codec comes from composed words compressor-decompressor or coder-decoder. Codec normally get the following 3 tasks:

• Decoding - Encoding
• Decompression - Compression
• Decryption - Encryption

Decoding - Encoding

When you call through normal PSTN phone, your tone is transmitted over the telephone line. But with Voice over Internet Protocol, your voice is changed into signals. The conversion is called encoding, and is obtained by a codec. When the digital voice goes to its destination, it needs to be decoded back to its original state so that the correspondent could understand and hear it.

Decompression - Compression

Bandwidth is a limited commodity. So, if the file or data to be sent out is created lighter, you could send more in a particular time amount, and thus enhance performance. To make the voice less massive, it is packed together. Compression is a difficult procedure whereby the similar data is saved but making use of lesser space. Throughout compression, the file or data is saved to a structure proper to the algorithm of compression. The compressed file is sent to the network and once it goes its destination, it is decompressed to its original state before decoding. In a lot of cases, but, it isn't needed to decompress the file back, because the compressed file is in a 'consumable' condition.

Decryption - Encryption

Encryption is the best tool for achieving protection. It is the procedure of changing the data to such a state that no one could understand. In this way, if the encrypted file is stopped by unauthorized individuals, the data still stays confidential. Once the encrypted file reaches the destination, it is decrypted to its original state. Usually, when the data is compressed, it is encrypted to a specific extent, because it is changed from its original state.