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and HDTV.
MPEG-4
On February, 1999 MPEG (Moving Picture Experts Group) formally issued the first version of
MPEG-4 (ISO/IEC14496) Standard. It became the formal international standard in 2000.
MPEG-4 is greatly different from MPEG-1 and MPEG-2. MPEG-4 is not only detailed
compression algorithm, but also a international standard established according to the requirements
of conformity and compression technique such as Digital TV, interactive graphics application
(video-audio synthesis), interactive multi-media (WWW, information retrieving and dispersion)
and so on. MPEG-4 standard concentrates numerous multi-media applications into a whole
structure, with its purpose to provide a standard algorithm and tools for the multi-media
communication and application environment. Thereby to build up a united digital format that
can be commonly used in application fields like multi-media transmission, storage and search.
DivX™ & XviD
DivX and XviD use the compression method of second part of MPEG-4. These two formats are
very popular as their Codec (software used for video and audio compression) is free of charge.
These two formats have a perfect quality comparable to MPEG-4, while their bit rates compressed
enough to be able to spread the videos on the internet. Thus it satisfies the practical demands of
most users.
DVD .ISO
ISO image (.iso) is an informal term of disk image of ISO 9660 file system. The contents of
CD/DVD disc can be converted to an ISO file. Generally, playing video ISO file is similar to
playing DVD disc in DVD player.
DVD .VOB
VOB (DVD-Video Object) is a kind of DVD-Video Media format, which includes real-time video,
audio, subtitle and operation menus. Single VOB file has the largest size of 1GB. Generally
there will be many VOB files, including IFO and BUP files. .IFO file is a DVD data file, which
stores relative information of DVD contents, subtitles and audio tracks. In the normal
circumstances, visiting VIDEO_TS/.IFO files is similar to playing DVD discs in DVD player.
VOB files can be directly visited.
A6.2 Music formats
WAV
Microsoft and IBM developed this kind of format together, which is also a most popular lossless
audio coding format. WAV files have flexible formats and can store many kinds of audio datum.
It is a good choice for saving original record data. WAV is a format on the basis of RIFF file
format. RIFF format is similar to AIFF and IFF format.
