IEI Technology iSignager 500A, Руководство пользователя

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iSignager 500A
Page 28
A.1 Overview of Video Formats
A.1.1 MPEG-1
MPEG-1 is a standard used to compress audio and video (AV) digital data. MPEG-1
defines a group of AV coding standards agreed upon by MPEG (Moving Picture Experts
Group). MPEG-1 video is used by the Video CD format. The output quality at usual
VCD bit rates is roughly that of a VCR. MPEG-1 audio layer 3 is the full name for the
popular audio format MP3. The MPEG-1 AV format was later extended into the MPEG-2
and MPEG-4 formats. These extensions allow for greater compression for the same size
of data.
A.1.2 MPEG-2
MPEG-2 is a standard used primarily to compress audio and video (AV) digital data.
MPEG-2 is the designation for a group of coding standards for AV, agreed upon by MPEG
(Moving Pictures Experts Group), and published as the ISO/IEC 13818 international
standard. MPEG-2 is typically used to encode audio and video for broadcast signals,
including direct broadcast satellite and Cable TV. MPEG-2, with some modifications, is
also the coding format used by standard commercial DVD movies.
A.1.3 MPEG-4
MPEG-4 is a standard used primarily to compress audio and video (AV) digital data. It is
the designation for a group of audio and video coding standards and related technology
agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG). The uses for the
MPEG-4 standard are web (streaming media) and CD distribution, conversational
(videophone), and broadcast television, all of which benefit from compressing the AV
stream.
A.1.4 DivX® and XviD
DivX is a video codec created by DivX, Inc. which has become popular due to its ability to
compress lengthy video segments into small sizes while maintaining relatively high visual