L64105 LSI Logic Corporation, L64105 Datasheet - Page 403

• Manufacturer Part Number: L64105
• Description: Mpeg-2 Audio/video Decoder
• Manufacturer: LSI Logic Corporation

Figure A.5
An MPEG pack is composed of a pack layer header , a system header
packet , a sequence of packets , and ends with an ISO 11172 end code.
The pack layer header contains a pack start code used for
synchronization purposes, and a system clock value. The system header
packet contains a variety of housekeeping data, in particular, a system
stream ID used to differentiate among multiple system streams. A
sequence of one or more packets contains either encoded audio or
encoded video stream data. The ISO 11172 end code is the final
element in an MPEG pack. For detailed definition of pack headers, refer
to the ISO/IEC 11172-1 system stream descriptions.
Any one MPEG packet carries either audio or video data, but not both
simultaneously. An MPEG Audio Packet contains an audio packet header
and one or more Audio Frames.
Figure A.6
Audio Compression and Decompression Concepts
Header
Contains:
Pack Start Code (32 bits),
System Clock Reference
(128 bits)
Header
Contains:
Packet
Layer
Packet Start Code
Packet Length
Presentation Time Stamps
Audio
Pack
System
Header
Packet
Frame
Audio
(first)
ISO System Stream
MPEG Audio Packet Structure
Audio Packet
Packet
(quantity varies)
(first)
Audio Frames
Various data, including
system stream ID
Contains:
Pack
More Packets
. . .
Contains:
Audio Frame Header
Audio Frame CRC
Audio Data
Ancillary/User Data
(variable #)
. . .
Figure A.6
Frame
Audio
(last)
Packet
(last)
Contains:
Audio stream data
(in audio frames)
shows the packet structure.
Audio Packet
End Code
11172
ISO
Pack
. . .
A-9