|
A codec is a device or computer program capable of encoding or decoding a digital data stream or signal.〔(【引用サイトリンク】title=Using codecs )〕〔(【引用サイトリンク】title=About.com - Codec )〕〔(【引用サイトリンク】title=Ubuntu Documentation - What is a codec? )〕 ''Codec'' is a portmanteau of ''coder-decoder'' or, less commonly, ''compressor-decompressor''. 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. A video camera's analog-to-digital converter (ADC) converts its analog signals into digital signals, which are then passed through a video compressor for digital transmission or storage. A receiving device then runs the signal through a video decompressor, then a digital-to-analog converter (DAC) for analog display. == Related concepts == In the mid 20th century, a codec was a hardware device that coded analog signals into digital form using pulse-code modulation (PCM). Late in the century the name was also applied to a class of software for converting between different digital signal formats, including compander functions. A modem is a contraction of ''modulator-demodulator''. The telecommunications industry referred to the device as a ''dataset''. It converts digital data from computers to analog signals for transmission over telephone lines. On the receiving end the analog signal is converted back to digital data. An audio codec converts analog audio signals into digital signals for transmission or storage. A receiving device then converts the digital signals back to analog using an audio decompressor, for playback. An example of this is the codecs used in the sound cards of personal computers. A video codec accomplishes the same task for video signals. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Codec」の詳細全文を読む スポンサード リンク
|