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The word codec is a portmanteau of 'compressor-decompressor' or, more commonly, 'coder-decoder'....A codec encodes a data stream or signal for transmission, storage or encryption, or decodes it for playback or editing. Codecs are used in videoconferencing, streaming media and video editing applications.

As with conventional telephony, with VoIP the speech is initially captured in analog form with a microphone. This analog information is then transferred into a digital format by a converter and changed through codecs into corresponding audio-binary formats. Depending on the codec used, the data can be compressed to differing extents in this process.

Most codecs use a procedure through which - similar to MP3 files - information not important for the human ear is omitted. This reduces the amount of data and thus reduces the bandwidth required for transfer. However, if too much information is omitted, the speech quality will suffer.

The different codec procedures master the audio compression with different levels of efficiency. Some are specifically designed to achieve a low bandwidth at any cost. Depending on the codec, therefore, the necessary bandwidth and the speech quality will vary. In order for the data also to be converted correctly back into speech after the transport, the receiver must use the same codec as the sender.

Supported codecs depends from the hardware and the firmware version too.

Since in order to reduce the SDP messages size not all codecs are enabled by default. Codecs can be manipulated trough the setting codec_priority_list

Please check the following pages for more details:


This category has the following 3 subcategories, out of 3 total.




Pages in category "Codec"

The following 8 pages are in this category, out of 8 total.



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