Cryptography Reference
In-Depth Information
The work of MPEG-1 started in May 1988, and was adopted as the inter-
national standards in 1993. MPEG-1 consists of the following five parts,
• ISO/IEC 111721, System, defines how multiple video and audio streams
can be multiplexed into one stream, and how synchronous playback can
be realized.
• ISO/IEC 111722, Video, compression standard.
• ISO/IEC 111723, Audio, compression standard. Level 3 of MPEG-1 audio
is the most popular standard for digital compression of audio known as
MP3.
• ISO/IEC 111724, Conformance testing, defines procedures to test validity
of bitstreams and compliance of decoders to the standard.
• ISO/IEC 111725, Software simulation, consists of a software decoder and
an encoder, that helps interested parties to get quickly accustomed to
MPEG Video and Audio.
Similar to H.261, MPEG-1 uses DCT based Intra frame coding to remove
the spatial redundancy, and motion compensation based Inter frame coding
to remove the temporal redundancy. It allows forward, backward, and inter-
polative predictions. The motion vectors will typically have the precision of
half pixel.
Constraint Parameter Set
MPEG-1 has recommended a constraint parameter set that the MPEG-1 com-
patible decoder must be able to support. The main purpose of having this set
of restrictions is to make sure that the decoder should be designed in a way
that it is competitive in terms of cost, and will not be easily put out of the
market. It should be noted that by no means the application of MPEG-1 is
limited to this constraint parameter set.
Parameters
CPS
PAL(SIF)
NTSC
Horizontal size (pixel)
720
352, 176
352, 176
vertical Size (pixel)
576
288, 144
240, 120
total # of MBs/pic
396
396
330
total # of MBs/sec
9900
9900
9900
picture rate
30
25
30
bit rate (Mbps)
1.86
1.5
1.5
decoder buffer (bits)
376832
MPEG-1 for Video CD
One of the most successful applications of MPEG-1 is its use in Video CD,
a requirement to shoehorn moving pictures into the data rate of a normal
White topic Compact Disc player. In order to meet the desperately low
