Codec

A codec is a compression standard.

• Raw video or audio is compressed when encoding, and decompressed (decoded) on playback.
• Codecs are used in videoconferencing, streaming media, and video editing applications.

Codec Basics

• Codecs are compression technologies and have two components, an encoder to compress the files, and a decoder to decompress.
• There are codecs for data (PKZIP), still images (JPEG, GIF, PNG), audio (MP3, AAC) and video (DivX,Cinepak, MPEG-4,MPEG-2,MPEG-1 H.264, VP8).

Types of CODECS

Codecs are divided into two categories. Lossless codecs and Lossy codecs.

• Lossless codecs retain all the information contained in the original stream thus preserving the audio/video quality in a signal.
• Lossy codecs reduce the quality to achieve compression but also use lower data bandwidth.

There are the list of video and audio codecs.

1. Video Codecs

A video codec is an electronic circuit or software that compresses or decompresses digital video.

• Devx 
• MPEG 1 (Moving Pictures Expert Group)
• Mpeg2 (m2v) 
• Mpeg4 (mp4)video 
• X vid 
• Dirac

2. Audio Codecs

An audio codec is a computer program used to compresses and decompresses digital audio data according to a given audio file or streaming media audio coding format.

• GSM – 13 Kbps (full rate), 20ms frame size.
• iLBC – 15Kbps,20ms frame size: 13.3 Kbps, 30ms frame size.
• ITU G.711 – 64 Kbps, sample-based. Also known as A-law/μ-law.
• ITU G719 – 32/48/64/128 Kbps, 28 ms Frame Size.
• ITU G.722 – 48/56/64 Kbps.
• ITU G.723.1 – 5.3/6.3 Kbps, 30ms frame size.
• ITU G.726 – 16/24/32/40 Kbps.
• ITU G.728 – 16 Kbps.
• ITU G.729 – 8 Kbps, 10ms frame size.
• Speex – 2.15 to 44.2 Kbps.
• LPC10 – 2.5 Kbps.
• DoD CELP – 4.8 Kbps.