Codec
- A codec is a software that is used to compress or decompress a digital media file, such as a video or song.
- It converts raw (uncompressed) digital video to a compressed format or vice versa.
- In the context of video compression, the “codec” can be dividing into 2 parts:
2) Decode.
The encoder performs the compression (encoding) function.
The decoder performs the decompression (decoding) function.
Common video codecs
1. MPEG (Motion Picture Experts Group):
- It is one of the biggest families in video codec.
- The MPG, MPE, MPA, M15, M1V, MP2 etc. are all from this family.
- MPEG format, including MPEG video, MPEG audio and MPEG (video, audio synchronization) of three parts:MPEG-1, MPEG-2 and MPEG-4.
i)MPEG-1:
Using MPEG-1 compression algorithm, a 120-minute film can be compressed to about the size of 1.2 GB, and the file format is generally mpg and dat files.
ii)MPEG-2: Transmission of videos for television
iii)MPEG-4:
The use of this compression algorithm can be a 120 minute film (the original video files) is compressed to about 300MB.
2. DivX
- It works with a certain type of MPEG-4 file, and was often used to rip DVDs in the pre-HD era.
- Most of the DivX videos use avi file extension, of course, DivX and Div extension.
3. XviD
- It is an open source version of DivX, popular among movie pirates.
- In general, theXvid decoder will be able to play all DivX media files.
- Most use Xvid encoded files to avi extension.
4. X264
- Which compresses H.264 videos (Also known as MPEG-4 AVC).
- It is very popular for high definition videos.