| A program or a device capable of performing | | | | established, you need to use a codec that is |
| encoding and decoding on a digital data stream or | | | | supported by both the parties and the provider. It is |
| signal is known as Codec. The stream or signal for | | | | imperative to understand codecs so as to enable you |
| transmission, storage or encryption are encoded and | | | | to have a better understanding as to why some |
| decoded by the Codecs. In the video camera, the | | | | VoIP service providers are better than others and |
| ADC converts its analogue signals to digital signals, | | | | also why audibility through IPS with some service |
| which after passing through the video compressor | | | | providers is better than others. In the following |
| for transmission or storage are decoded by the DAC | | | | paragraphs, the different types of codecs and their |
| for analog display. An audio compressor converts | | | | utility are elaborated. |
| analogue audio signals to digital signals for | | | | There are basically three types of codecs namely |
| transmission or storage. The de-compressor at the | | | | Audio codecs, Video codecs, and Data codecs. |
| receiving end converts the digital signals back to | | | | Audio codec - A computer program which |
| analog for playback. Essence is a term commonly | | | | compresses/decompresses digital audio data is |
| associated with the raw encoded form of audio and | | | | known as audio codec. Most of these codecs are |
| video data. | | | | implemented as libraries that act as an interface to |
| Codec is an algorithm used to code and decode the | | | | one or more multimedia players such as Winamp, |
| voice conversation in case of VoIP. The voice and | | | | XMMS and Windows Media Player. At times, the audio |
| sound that we hear is in analogue form and needs to | | | | codec can refer to a hardware implementation or |
| be converted into a digital form for transmission over | | | | sound card. In such a context, the term audio codec |
| Internet. On the other side, it needs to be decoded | | | | actually refers to a combined audio AD/DA converter |
| once again to make it easy to hear for the recipient. | | | | and a fine example of this would be the Intel |
| The coding and decoding can be done in different | | | | Corporation's AC'97. |
| ways by utilizing compression to reduce the | | | | Video codec is the device or software module that |
| bandwidth of the conversation. It is pertinent to | | | | enables the use of data compression for digital |
| mention that with VoIP, encoding with heavy | | | | videos. Initially, videos were stored on magnetic |
| compression takes more time and delays the | | | | tapes as an analogue signal. However with the |
| conversation. It is here that the codec becomes | | | | evolution of compact discs, it became feasible to |
| eminent for it not only maintains good quality with | | | | store and use video in a digital form. A combination |
| compression but also does the encoding and decoding | | | | of audio and video calls for customized methods of |
| in a reasonable time. | | | | compression. There lies the complexity between |
| Different VoIP clients support different codecs and | | | | video quality bit rate, the complexity of coding and |
| each VoIP service provider supports the subset of a | | | | decoding, robustness of data loss and error, random |
| codec. In simpler terms when a VoIP call is | | | | access and the art of compression. |