Method to Synchronize Local Moving Picture Expert's Group Decoder in Incoming Moving Picture Expert's Group Data Stream
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Combs, J: AUTHOR [+1]
Disclosed is a method to synchronize a local Moving Picture Expert's Group (MPEG) decoder subsystem to an incoming MPEG data stream.
Method to Synchronize Local Moving Picture Expert's Group
in Incoming Moving Picture Expert's Group Data Stream
a method to synchronize a local Moving Picture
Expert's Group (MPEG) decoder subsystem to an incoming MPEG data
As shown in
the Figure, a typical design for a digital
set-top box includes a buffer to hold MPEG data as it comes from the
receiver. The receiver may be a Satellite Microwave receiver, a
terrestrial Radio Frequency (RF) receiver, a cable RF receiver, or
even a Direct View Display (DVD) disk. MPEG data is taken as it
becomes available and put into a First In First Out (FIFO) buffer.
Data is taken from the buffer as needed by the decoder subsystem.
One of the
larger cost hits to a digital set-top box system is
the amount of Random Access Memory (RAM) required for the local
buffer. It is very beneficial to minimize the size required for this
It is a
requirement that the local MPEG decoder subsystem
handle the MPEG data at the same rate as the incoming data stream for
several reasons. If the local decoder is running faster than
incoming data, the local buffer will become empty and force the
decoder to stop while more data is received. If the local decoder is
running slower than the incoming data, the local buffer will fill
up. This will force the set-top box to skip some portion of the MPEG
data stream. Both of these conditions are apparent to the viewer and
should be considered a must avoid problem for designers of digital
set-top decoder systems.
clock used by the MPEG decoder is the 27 MHz and is